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  • 1
    Publication Date: 2022-01-31
    Description: This volume contains 17 peer-reviewed papers based on the presentations at the 9th Annual International Workshop on Bioinformatics and Systems Biology (IBSB 2009) held at the Life Science Engineering Building of Boston University from July 27 to 29, 2009. This workshop started in 2001 as a platform for doctoral students and young researchers to present and discuss their research results and approaches in bioinformatics and systems biology. It is part of a collaborative educational program involving leading institutions and leaders committed to the following institutions and programs: Boston University Graduate Program in Bioinformatics Charité – Universitätsmedizin Berlin Freie Universität Berlin Global COE Program — Center of Education and Research for Advanced Genome-Based Medicine, University of Tokyo The International Research Training Group (IRTG) Genomics and Systems Biology of Molecular Networks International Research and Training Program on Bioinformatics and Systems Biology, Kyoto University Bioinformatics Center Max-Delbrück Center for Molecular Medicine in Berlin Max Planck Institute for Molecular Genetics in Berlin Max Planck Institute of Molecular Plant Physiology in Potsdam
    Keywords: Computational Biology ; Genetics ; Genome Informatics ; Bioinformatics ; Systems Biology
    Language: English
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  • 2
    Publication Date: 2023-12-21
    Description: In the spring of 2011, a diverse group of scientists gathered at Cornell University to discuss their research into the nature and origin of biological information. This symposium brought together experts in information theory, computer science, numerical simulation, thermodynamics, evolutionary theory, whole organism biology, developmental biology, molecular biology, genetics, physics, biophysics, mathematics, and linguistics. This volume presents new research by those invited to speak at the conference. The contributors to this volume use their wide-ranging expertise in the area of biological information to bring fresh insights into the many explanatory difficulties associated with biological information. These authors raise major challenges to the conventional scientific wisdom, which attempts to explain all biological information exclusively in terms of the standard mutation/selection paradigm. Several clear themes emerged from these research papers: 1) Information is indispensable to our understanding of what life is; 2) Biological information is more than the material structures that embody it; 3) Conventional chemical and evolutionary mechanisms seem insufficient to fully explain the labyrinth of information that is life. By exploring new perspectives on biological information, this volume seeks to expand, encourage, and enrich research into the nature and origin of biological information. Contents: Session One — Information Theory & Biology: Introductory Comments (Robert J Marks II): Biological Information — What is It? (Werner Gitt, Robert Compton and Jorge Fernandez) A General Theory of Information Cost Incurred by Successful Search (William A Dembski, Winston Ewert and Robert J Marks II) Pragmatic Information (John W Oller, Jr) Limits of Chaos and Progress in Evolutionary Dynamics (William F Basener) Tierra: The Character of Adaptation (Winston Ewert, William A Dembski and Robert J Marks II) Multiple Overlapping Genetic Codes Profoundly Reduce the Probability of Beneficial Mutation (George Montañez, Robert J Marks II, Jorge Fernandez and John C Sanford) Entropy, Evolution and Open Systems (Granville Sewell) Information and Thermodynamics in Living Systems (Andy C McIntosh) Session Two — Biological Information and Genetic Theory: Introductory Comments (John C Sanford): Not Junk After All: Non-Protein-Coding DNA Carries Extensive Biological Information (Jonathan Wells) Can Purifying Natural Selection Preserve Biological Information? (Paul Gibson, John R Baumgardner, Wesley H Brewer and John C Sanford) Selection Threshold Severely Constrains Capture of Beneficial Mutations (John C Sanford, John R Baumgardner and Wesley H Brewer) Using Numerical Simulation to Test the “Mutation-Count” Hypothesis (Wesley H Brewer, John R Baumgardner and John C Sanford) Can Synergistic Epistasis Halt Mutation Accumulation? Results from Numerical Simulation (John R Baumgardner, Wesley H Brewer and John C Sanford) Computational Evolution Experiments Reveal a Net Loss of Genetic Information Despite Selection (Chase W Nelson and John C Sanford) Information Loss: Potential for Accelerating Natural Genetic Attenuation of RNA Viruses (Wesley H Brewer, Franzine D Smith and John C Sanford) DNA.EXE: A Sequence Comparison between the Human Genome and Computer Code (Josiah Seaman) Biocybernetics and Biosemiosis (Donald Johnson) Session Three — Theoretical Molecular Biology: Introductory Comments (Michael J Behe): An Ode to the Code: Evidence for Fine-Tuning in the Standard Codon Table (Jed C Macosko and Amanda M Smelser) A New Model of Intracellular Communication Based on Coherent, High-Frequency Vibrations in Biomolecules (L Dent) Getting There First: An Evolutionary Rate Advantage for Adaptive Loss-of-Function Mutations (Michael J Behe) The Membrane Code: A Carrier of Essential Biological Information That is Not Specified by DNA and is Inherited Apart from It (Jonathan Wells) Explaining Metabolic Innovation: Neo-Darwinism Versus Design (Douglas D Axe and Ann K Gauger) Session Four — Biological Information and Self-Organizational Complexity Theory: Introductory Comments (Bruce L Gordon): Evolution Beyond Entailing Law: The Roles of Embodied Information and Self Organization (Stuart Kauffman) Towards a General Biology: Emergence of Life and Information from the Perspective of Complex Systems Dynamics (Bruce H Weber) Readership: Academics, researchers, postgraduates and advanced undergraduates in bioinformatics. Biologists, mathematicians/statisticians, physicists and computer scientists.
    Keywords: T1-995 ; Molecular Biology ; Mutation/Selection Paradigm ; Numerical Simulation ; Mathematics ; Biophysics ; Physics ; Thermodynamics ; Information Theory ; Evolutionary Theory ; Computer Science ; Linguistics ; Genetics ; Developmental Biology ; Biological Information ; Whole Organism Biology ; bic Book Industry Communication::T Technology, engineering, agriculture::TB Technology: general issues
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  • 3
    Publication Date: 2022-05-26
    Description: © 2009 The Authors. This is an open-access article distributed under the terms of the Creative Commons Attribution Noncommercial License. The definitive version was published in Coral Reefs 28 (2009): 327-337, doi:10.1007/s00338-009-0466-z.
    Description: Design and decision-making for marine protected areas (MPAs) on coral reefs require prediction of MPA effects with population models. Modeling of MPAs has shown how the persistence of metapopulations in systems of MPAs depends on the size and spacing of MPAs, and levels of fishing outside the MPAs. However, the pattern of demographic connectivity produced by larval dispersal is a key uncertainty in those modeling studies. The information required to assess population persistence is a dispersal matrix containing the fraction of larvae traveling to each location from each location, not just the current number of larvae exchanged among locations. Recent metapopulation modeling research with hypothetical dispersal matrices has shown how the spatial scale of dispersal, degree of advection versus diffusion, total larval output, and temporal and spatial variability in dispersal influence population persistence. Recent empirical studies using population genetics, parentage analysis, and geochemical and artificial marks in calcified structures have improved the understanding of dispersal. However, many such studies report current self-recruitment (locally produced settlement/settlement from elsewhere), which is not as directly useful as local retention (locally produced settlement/total locally released), which is a component of the dispersal matrix. Modeling of biophysical circulation with larval particle tracking can provide the required elements of dispersal matrices and assess their sensitivity to flows and larval behavior, but it requires more assumptions than direct empirical methods. To make rapid progress in understanding the scales and patterns of connectivity, greater communication between empiricists and population modelers will be needed. Empiricists need to focus more on identifying the characteristics of the dispersal matrix, while population modelers need to track and assimilate evolving empirical results.
    Description: Work by CB Paris was supported by the National Science Foundation grant NSF-OCE 0550732. Work by M-A Coffroth and SR Thorrold was supported by the National Science Foundation grant NSF-OCE 0424688. Work by TL Shearer was supported by an International Cooperative Biodiversity Group grant R21 TW006662-01 from the Fogarty International Center at the National Institutes of Health.
    Keywords: Connectivity ; Larval dispersal ; Marine protected areas ; Resilience ; Replacement ; Genetics
    Repository Name: Woods Hole Open Access Server
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  • 4
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    Entomologia experimentalis et applicata 60 (1991), S. 173-182 
    ISSN: 1570-7458
    Keywords: Genetics ; evolution ; host adaptation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract When populations are exposed to different environments, evolutionary processes can lead either to genetically differentiated strains or to the appearance of increased generalism at the individual level. For evolution to occur, genetic variability in performance in different environments is required. Here, intraspecific genetic variation across environments was estimated in the flour beetle Tribolium castaneum (Herbst) by comparing the responses of two strains of T. castaneum to different flour types. Replicated groups from each strain were allowed to develop on either the standard whole wheat medium or on one of four novel flours (wheat, rice, corn and oat). In several of the novel flours, clear differences in mean development time or population size of one or both strains were seen relative to performance in the standard medium. Moreover, the strains differed significantly in their phenotypic responses to the flours. One strain did particularly poorly on oat flour. Reduced oviposition, reduced larval survivorship and increased larval cannibalism were examined as possible causes of the low productivity on oat flour. These three factors accounted for about 70% of the reduction in population size when this strain oviposited and developed in oat flour. The difference between these two outbred strains in response to these five flours suggests that genetic variation in resource use is present within T. castaneum and may also be present within strains and natural populations in grain storage facilities. Such variation would permit an evolutionary response to selection in multiple environments (flours). This process has agricultural implications when several types of grain are stored in a single location because it could eventually lead to the evolution of highly generalized populations of T. castaneum, an important pest of stored products.
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  • 5
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    Entomologia experimentalis et applicata 34 (1983), S. 215-220 
    ISSN: 1570-7458
    Keywords: Oviposition preference ; Genetics ; Oncopeltus fasciatus ; Hemiptera ; Lygaeidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Bei Oncopeltus fasciatus von 6 verschiedenen Herkünften und deren F1 und F2 Hybriden wurde die bevorzugte Eiablagestelle untersucht. In drei Versuchsreihen erwiesen sich dabei alle an einer Lokalität gesammelten Proben als statistisch homogen. Ferner bilderen alle in Nordamerika gesammelten Proben eine statistisch homogene Gruppe, die sich von der puertoricanischen Herkunft unterschied. F1 and F2 Hybriden nicht puertoricanischer Herkunft unterschieden sich nicht wesentlich voneinander. Hybriden zwischen puertoricanischen und nordame-rikanischen Herkünften zeigten in F1 eine dominante Neigung in Richtung der puertoricanischen Eiablagepräferenz; diese Neigung verlor sich in F2. Aufgrund dieses Verlusts wurde geschlossen, dass die Eiablagepräferenz polygenisch bestimmt ist.
    Notes: Abstract Oviposition site preferences were examined in descendents of milkweed bugs collected in six geographic areas and in their F1 and F2 hybrids. Within an area, samples were stastically homogeneous in oviposition preference across three trials. All samples from within the continental USA formed a statistically homogeneous group and, as a group, were different in oviposition preference from the Puerto Rican collection. F1 and F2 hybrids with no Puerto Rican ancestry were not significantly different from each other in oviposition preference. Hybrids with Puerto Rican ancestry exhibited a “dominance” deviation in favor of the Puerto rican oviposition site preference in the F1 generation, but lost that deviation in the F2 generation. This loss was interpreted as evidence that oviposition preference in Oncopeltus fasciatus was polygenically controlled. Probable selection pressures affecting oviposition preferences in O. fasciatus and the advantages of polygenic control of this trait were discussed.
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  • 6
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    Journal of insect behavior 3 (1990), S. 579-587 
    ISSN: 1572-8889
    Keywords: Genetics ; polymorphism ; reproductive isolation ; hovering behavior ; Tabanus nigrovittatus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The salt marsh horse fly, Tabanus nigrovittatusMacquart, exhibits two nonoverlapping daily periods of hovering and mating activity, which are correlated with different environmental temperatures. Allelic and genotypic frequencies of hovering males collected during the two periods were compared by electrophoresis of three polymorphic enzyme loci. Approximately 26% of early-hovering males possessed a Pgmallozyme that was absent in our sample of late-hovering males. However, based on other allozyme loci, we found no evidence for reproductive isolation between early and late hoverers. All the genetic data are consistent with the hypothesis that the Pgmpolymorphism is associated with behaviorally and physiologically distinct groups of males that, by all other criteria, form a single Mendelian population.
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  • 7
    ISSN: 1572-8773
    Keywords: Iron transport ; Siderophores ; Pseudomonas putida ; Genetics ; Receptors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary Root-colonizingPseudomonas putida WCS358 enhances growth of potato in part by producing under iron-limiting conditions a yellow-green, fluorescent siderophore designated pseudobactin 358. This siderophore efficiently complexes iron(III) in the rhizosphere, making it less available to certain endemic microorganisms, including phytopathogens, thus inhibiting their growth. At least 15 genes distributed over five gene clusters are required for the biosynthesis of pseudobactin 358. High-affinity iron(III) transport in strain WCS358 is initiated by an 86-kDa outer membrane receptor protein (PupA) which appears to be specific for ferric pseudobactin 358. PupA shares strong similarity with TonB-dependent receptor proteins ofEscherichia coli, which suggests a TonB-like protein in strain WCS358 is required for iron(III) transport. Strain WCS358 possesses a second uptake system for ferric pseudobactin 358 and structurally diverse ferric siderophores produced by other microorganisms. A second receptor gene (pupB) responsible for iron transport from pseudobactin BN7 or pseudobactin BN8 has been identified. The production of this and certain other ferric siderophore receptor proteins requires that strain WCS358 be grown in the presence of these siderophores. An apparent regulatory gene required for the expression ofpupB is located adjacent topupB. Two positive regulatory genes have been identified which can independently activate, under low-iron(III) conditions, transcription of genes coding for the biosynthesis of pseudobactin 358.
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  • 8
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    Cellular and molecular life sciences 50 (1994), S. 429-437 
    ISSN: 1420-9071
    Keywords: Genetics ; ecology ; DNA-transfer ; conjugation ; transformation ; transduction ; transposons ; dormant cells ; epilithon ; microbial colonisation ; symbiosis ; virus resistance ; biosafety ; release of genes ; insults to humanity ; evolution ; biodiversity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Genetic ecology is the extension of our modern knowledge in molecular genetics to studies of viability, gene expression and gene movements in natural environments like soils, aquifers and digestive tracts. In such milieux, the horizontal transfer of plasmid-borne genes between phylogenetically distant species has already been found to be much more frequent than had been expected from laboratory experience. For the study of exchanges involving chromosomally-located genes, more has to be learned about the behaviour of transposons in such environments. The results expected from studies in genetic ecology are relevant for considerations of evolution, biodiversity and biosafety. The role of this new field of research in restoring popular confidence in science and in its biotechnological applications is stressed.
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  • 9
    ISSN: 1432-0983
    Keywords: Chlamydomonas ; Chloroplast ; DNA ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The density, molecular weight, and cellular repetition of DNA molecules associated with the β-DNA satellite of the interfertile algae Chlamydomonas eugametos and C. moewusii are reported. The similarities between these values and those for the chloroplast DNA (cpDNA) in the related alga Chlamydomonas reinhardtii indicate that these satellites represent cpDNA. The buoyant densities of C. eugametos and C. moewusii cpDNAs are indistinguishable from one another, as are those of their respective nuclear DNAs. These densities differ slightly from the densities of the homologous components of C. reinhardtii whole cell DNA. All three species differ with respect to additional minor satellite DNAs and low molecular weight DNAs of unknown cellular location. Differences in the Aval and Smal restriction endonuclease fragmentation patterns of C. eugametos and C. moewusii cpDNAs were employed to study the inheritance of cpDNA in an F1 hybrid which had inherited a non-Mendelian streptomycin resistance marker (sr-2) from the C. eugametos mating-type plus (mt +) parent and in two homoplasmic mitotic segregants from a B 1 hybrid (F1 × C. moewusii) which had been initially heteroplasmic for the resistance marker. Although the cpDNA patterns in the F1 hybrid were similar to those of the C. eugametos ml 1 parent, important differences were noted which suggest that recombination between C. eugametos and C. moewusii cpDNA had occurred. Homoplasmic streptomycin resistant and sensitive mitotic segregants recovered from the B1 hybrid product reveal Aval restriction patterns similar to those of the respective resistant and sensitive parents. These data are consistent with the hypothesis that the sr-2 marker is located in cpDNA and that C. eugametos and C. moewusii cpDNA sequences can coexist in the same chloroplast and, at least sometimes, segregate without extensive recombination. The transmission of low molecular weight DNAs characteristic of C. moewusii but of unknown cellular origin shows no direct correlation with the transmission of the sr-2 marker.
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  • 10
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    Journal of molecular evolution 16 (1980), S. 211-267 
    ISSN: 1432-1432
    Keywords: Nucleic acids ; Proteins ; Natural selection ; Genetics ; Nonrandom molecular divergence ; Nonrandom REH theory ; Evolution ; mRNA ; DNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary REH theory is extended by deriving the theoretical equations that permit one to analyze the nonrandom molecular divergence of homologous genes and proteins. The nonrandomicities considered are amino acid and base composition, the frequencies with which each of the four nucleotides is replaced by one of the other three, unequal usage of degenerate codons, distribution of fixed base replacements at the three nucleotide positions within codons, and distributions of fixed base replacements among codons. The latter two distributions turn out to dominate the accuracy of genetic distance estimates. The negative binomial density is used to allow for the unequal mutability of different codon sites, and the implications of its two limiting forms, the Poisson and geometric distributions, are considered. It is shown that the fixation intensity — the average number of base replacements per variable codon - is expressible as the simple product of two factors, the first describing the asymmetry of the distribution of base replacements over the gene and the second defining the ratio of the average probability that a codon will fix a mutation to the probability that it will not. Tables are given relating these features to experimentally observable quantities inα hemoglobin,β hemoglobin, myoglobin, cytochromec, and the parvalbumin group of proteins and to the structure of their corre-sponding genes or mRNAs. The principal results are (1) more accurate methods of estimating parameters of evolutionary interest from experimental gene and protein sequence data, and (2) the fact that change in gene and protein structure has been a much less efficient process than previously believed in the sense of requiring many more base replacements to effect a given structural change than earlier estimation procedures had indicated. This inefficiency is directly traceable to Darwinian selection for the nonrandom gene or protein structures necessary for biological function. The application of these methods is illustrated by detailed consideration of the rabbitα -andβ hemoglobin mRNAs and the proteins for which they code. It is found that these two genes are separated by about 425 fixed base replacements, which is a factor of two greater than earlier estimates. The replacements are distributed over approximately 114 codon sites that were free to accept base mutations during the divergence of these two genes.
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  • 11
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    Journal of molecular evolution 17 (1981), S. 167-181 
    ISSN: 1432-1432
    Keywords: Evolution ; Genetics ; REH theory ; Mutations ; Natural selection ; Nucleic acids ; Proteins ; Paleogenetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have independently repeated the computer simulations on which Nei and Tateno (1978) base their criticism of REH theory and have extended the analysis to include mRNAs as well as proteins. The simulation data confirm the correctness of the REH method. The high average value of the fixation intensity μ2 found by Nei and Tateno is due to two factors: 1) they reported only the five replications in which μ2 was high, excluding the forty-five replications containing the more representative data;and 2) the lack of information, inherent to protein sequence data, about fixed mutations at the third nucleotide position within codons, as the values are lower when the estimate is made from the mRNAs that code for the proteins. REH values calculated from protein or nucleic acid data on the basis of the equiprobability of genetic events underestimate, not overestimate, the total fixed mutations. In REH theory the experimental data determine the estimate T2 of the time average number of codons that have been free to fix mutations during a given period of divergence. In the method of Nei and Tateno it is assumed, despite evidence to the contrary, that every amino acid position may fix a mutation. Under the latter assumption, the measure X2 of genetic divergence suggested by Nei and Tateno is not tenable: values of X2 for theα hemoglobin divergences are less than the minimum number of fixed substitutions known to have occurred. Within the context of REH theory, a paradox, first posed by Zuckerkandl, with respect to the high rate of covarion turnover and the nature of general function sites in proteins is resolved.
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  • 12
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    Journal of biomedical science 1 (1994), S. 201-203 
    ISSN: 1423-0127
    Keywords: Hypertension ; Eicosanoid ; Rat ; Genetics ; Kidney
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The present paper reviews the evidence for a possible involvement of renal eicosanoids in the pathophysiology of high blood pressure in genetically hypertensive rats of the Lyon strain. Both in vivo and in vitro experiments suggest that an increased ability to synthesize the vasoconstrictor prostaglandin H2 and/or thromboxane A2 in renal vessels (1) acts as an autocrine amplifier of pressor agents and (2) may contribute to resetting the pressure natriuresis curve which is a prerequisite for the development and maintenance of hypertension.
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  • 13
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    Oecologia 86 (1991), S. 243-250 
    ISSN: 1432-1939
    Keywords: Daphnia ; Life-history ; Genetics ; Variation ; Maturation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Life-history traits of 101 clones from two populations of Daphnia magna were measured under controlled environmental conditions in the laboratory. Some individuals had four juvenile instars, others had five. This depended on their length at birth and on the population they came from. Females in the group with five juvenile instars were smaller at birth but larger and older at maturity than those with four juvenile instars. Within groups of females with equal numbers of preadult instars (instar groups) age and size at maturity increased with size at birth. This relationship differed significantly among instar groups for both age and size at maturity. Significant differences in age and size at maturity between two populations became non-significant when size at birth was used as a covariable in AN-COVA. Within populations, size at birth depended on the clone and on the parity of the clutch. First-clutch offspring were considerably smaller than those from later clutches. The results suggest that variability in life-history traits is common within and between clones, but that most of this variation can be accounted for by size at birth and the number of pre-adult instars.
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  • 14
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    Sexual plant reproduction 7 (1994), S. 290-296 
    ISSN: 1432-2145
    Keywords: Secale cereale ; Polyembryony ; Chromosome mosaics ; Rye ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have obtained one plant regenerated from rye tissue culture which showed a high percentage of polyembryonic seeds in its progeny. The mutation inducing the development of extra embryos is also influencing erroneous cell division, mitosis and meiosis. The genetic analysis indicated that the aptitude for polyembryonic seed formation is a heritable trait controlled by a dominant gene. However, for expression of the phenotype the female parent should have a specific cytoplasm.
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  • 15
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    Sexual plant reproduction 3 (1990), S. 31-34 
    ISSN: 1432-2145
    Keywords: Mucoraceae ; Zygomycetes ; Homothallic ; Genetics ; Nutritional complementation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Auxotrophic strains of Mucor genevensis and Zygorhynchus exponens were crossed and the resulting zygospores germinated. The presence of a true sexual cycle in both species was demonstrated by the recovery of recombinant genotypes. Expected Mendelian ratios were not realized, however. The presence of selfed zygospores among those isolated makes this observation understandable. It was possible to demonstrate nutritional complementation when young mating mycelium was transferred to minimal medium and forced heterokaryons were recovered.
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  • 16
    ISSN: 1432-0983
    Keywords: Protoplast ; Fusion ; Mitochondrial ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Using a protoplast fusion technique we have been able to locate to the mitochondrial genome of the asporogenous yeast Torulopsis glabrata mutations conferring resistance to oligomycin, antimycin and diuron. When two strains differing in the size of their mtDNAs were fused the mitochondrial markers from the parent with the larger mtDNA (71–91) were transmitted predominantly among the fusion products. Both genetical and physical evidence support the occurrence of recombination in T. glabrata mitochondrial genome. Segregation of the mitochondrial genome appears to take place before the separation of the first bud from the fusion product.
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  • 17
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    Current genetics 4 (1981), S. 177-180 
    ISSN: 1432-0983
    Keywords: Genetics ; Yeasts, protoplasts ; Saccharomyces ; Hansenula
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Protoplasts of petites of strains 625-CI of Saccharomyces diastaticus and NCYC 1085 of Saccharomyces cerevisiae, originally obtained from the National Collection of Yeast Cultures, England, were fused with protoplasts of Candida pseudotropicalis, Saccharomyces rosei, Yaccharbmycesmontanus, Pichiamembranefaciens, Hansenula anomala, Hansenula capsulata, and Schizosac-charomyces pombe. The respiratory-competent products of the fusions were selected on the basis of using at least one of the carbon sources utilized by the petite parent and not by the other. The products of the fusion of C. pseudotropicalis x 1085(p−) consisted of two cell types; an oval cell which utilized both lactose and maltose and fermented lactose vigorously, and a cylindrical form which fermented maltose slowly. The S. rosei x 1085(p−) hybrids had acquired the ability to metabolize and ferment galactose, and to ferment maltose, from the petite parent. The P. membranaefaciens x 625(p−) hybrids acquired the ability to metabolize galactose, sucrose and maltose, but fermented only glucose, weakly, like the P. membranaefaciens parent strain. The H. capsulate x 625(p−) hybrids, unlike the hybrids with P. membranaefaciens or S. rosei, resembled the petite parent morphologically and also had the fermentative abilities of this strain (galactose, maltose, sucrose and starch), and the ability to ferment starch was considerably enhanced. The S. montanus x 625(p−) hybrids acquired the ability to utilize starch. Schizosaccharomyces pombe x 625(p−) hybrids resembled S. pombe morphologically, but had the ability to metabolize galactose and starch. Some of the asci produced by these hybrids contained abnormal numbers of spores. H. anomala x 624 x(p−) hybrids fermented starch, though weakly.
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  • 18
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    Journal of comparative physiology 166 (1990), S. 545-552 
    ISSN: 1432-1351
    Keywords: Honeybees ; Learning ; Classical conditioning ; Selection ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Four strains of the honeybee (Apis mellifera capensis), which were selected for high (N=2) or low (N=2) performance levels in classic conditioning of olfactory and mechanosensory stimuli, were examined in two instrumental visual learning tasks. Bees were trained to coloured cardboards either at the hive entrance or at the feeding station. Positive correlations were detected between olfactory/mechanosensory conditioning and visual learning. Good and poor learners from strains selected for olfactory conditioning differed significantly in their visual learning values. These strain differences reflect genetic differences in a common learning system rather than task specific differences in sensory, motor or motivational components. Parameters that were influenced by activity of the colony (duration of stay at the feeding place, time between visits) also differed among selected strains. These effects were not due to selection. Instead, they reflect a specific genetic background produced in each strain independently of selection. The results indicate that associative learning has a genetic basis which is independent of the sensory stimuli associated with reward, the learning procedure (classical conditioning or instrumental learning) or the motor patterns used to execute the learned behavior (proboscis extension, control for flight behavior, open field orientation).
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  • 19
    ISSN: 1432-072X
    Keywords: Carboxydotrophic bacteria ; Ribulosebis-phosphate carboxylase ; Phosphoribulokinase ; Hybridization ; Plasmids ; Genetics ; CO2 fixation ; Alcaligenes eutrophus ; Pseudomonas carboxydovorans ; Rhodospirillum rubrum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Heterologous gene probes derived from cfxLp and cfxPp genes of Alcaligenes eutrophus H16 revealed the presence of structural genes encoding ribulosebisphosphate carboxylase (Rubisco) and phosphoribulokinase (PRK) on the genome of carboxydotrophic bacteria. The two genes were found to be rather conserved. In Pseudomonas carboxydovorans OM5 cfx genes reside on the plasmid pHCG3 and the chromosome as well, indicating that they are duplicated. Also in all plasmidharboring carboxydotrophic bacteria cfxL and cfxP structural genes were found to be plasmid-coded. Our results extend the list of carboxydotrophy structural genes residing on the plasmid pHCG3 and strongly support the idea that the components essential for the chemolithoautotrophic utilization of CO by Pseudomonas carboxydovorans OM5 are plasmid-coded. A cfxL gene probe from Rhodospirillum rubrum did not detectably hybridize with DNA from any of the carboxydotrophic bacteria examined.
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    Journal of mathematical biology 15 (1982), S. 65-77 
    ISSN: 1432-1416
    Keywords: Epidemics ; Genetics ; Continuous models
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Abstract Continuous deterministic models are used to investigate the relationship between the epidemiology of endemic infectious disease and the genetics of natural selection in the host population when a specific genetic locus controls susceptibility to disease under a variety of circumstances. One locus, two allele genes are considered in the contexts of haploid and diploid host populations while the agent of infection is assumed to be invariant. It is found that polymorphic equilibria exist and are stable for certain parameter combinations in each of the cases studied. The equilibrium levels of gene frequencies and disease prevalence depend on both genetic and epidemic factors.
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    Journal of mathematical biology 17 (1983), S. 289-304 
    ISSN: 1432-1416
    Keywords: Endemicity ; Epidemics ; Genetics ; Deterministic models ; Stability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Abstract A discrete time genetics model is developed for populations that are undergoing selection due to infectious disease. It is assumed that the generation time of the host and infectious agent are non-synchronous and that only the host population is evolving. Two classes of epidemic processes are considered. The first class is for infectious agents that confer immunity following infection, while the second class is for those that do not confer immunity. The necessary and sufficient conditions are found in order for the disease to persist in a stable polymorphic host population. These conditions are shown to depend on the density of susceptibles, the selection coefficients, and the severity and class of the disease process.
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  • 22
    ISSN: 1432-1343
    Keywords: Analysis of variance ; Choropleth map ; Ecology ; Genetics ; Geography ; Permutation test ; Spatial autocorrelation
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    Topics: Mathematics
    Description / Table of Contents: Résumé Cet article présente une solution au problème de l'analyse de variance, pour certains cas où la variable à analyser est spatialement autocorr élée alors que le critère de classification représente des sous-régions connexes du territoire à l'étude. On sait que les méthodes classiques d'analyse de variance ne sont pas applicables dans ce type de situation puisque la condition d'indépendance des échantillons n'est pas respectée; l'autocorrélation positive réduit la variabilité intragroupe, si bien que la quantité relative de variabilité intergroupe s'en trouve artificiellement augmentée. Cette situation correspond en réalité à une vaste catégorie de problèmes en génétique des populations, en écologie et dans d'autres branches de la biologie, ainsi qu'en épidémiologie, en géographie, en géologie, en science économique, en science politique et en sociologie. Ce nouveau test appartient à la famille des tests par permutation. Nous calculons la somme des dispersions intragroupes et testons contre une distribution de référence obtenue en permutant les régions géographiques un grand nombre de fois sur la carte. La véritable difficulté de ce test est d'ordre algorithmique, puisqu'il n'est pas facile de permuter des régions sur une carte, de façon à ce que chaque groupe demeure connexe, et que la carte permutée occupe le même espace total que la carte d'origine. Cet article présente la théorie, les algorithmes, ainsi que des résultats obtenus par cette méthode. Un programme écrit en PASCAL est disponible.
    Notes: Abstract The classical method for analysis of variance of data divided in geographic regions is impaired if the data are spatially autocorrelated within regions, because the condition of independence of the observations is not met. Positive autocorrelation reduces within-group variability, thus artificially increasing the relative amount of among-group variance. Negative autocorrelation may produce the opposite effect. This difficulty can be viewed as a loss of an unknown number of degrees of freedom. Such problems can be found in population genetics, in ecology and in other branches of biology, as well as in economics, epidemiology, geography, geology, marketing, political science, and sociology. A computer-intensive method has been developed to overcome this problem in certain cases. It is based on the computation of pooled within-group sums of squares for sampled permutations of internally connected areas on a map. The paper presents the theory, the algorithms, and results obtained using this method. A computer program, written in PASCAL, is available.
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  • 23
    ISSN: 1432-2242
    Keywords: Triticum aestivum L. ; Doubled-haploids ; Genetics ; Androgenesis
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    Notes: Summary Plants of three common wheat (Triticum aestivum L. em. Thell) cultivars and one randomly selected doubled-haploid line derived by anther culture from each of the three cultivars were each grown in three environments, a field environment, a greenhouse environment, and a growth chamber environment. Anthers containing largely miduninucleate to late uninucleate microspores were cultured and calli were induced to regenerate plants in order to assess the effects of cultivar, cultivar family (cultivar and corresponding doubled-haploid derivative), anther-donor plant environment, and cultivar X environment interaction on androgenic responses. Large differences in response were observed among cultivars as well as between cultivars and doubled-haploids. Differences between cultivar and doubled-haploid within cultivar family usually resulted from higher frequency of response in the cultivar, contrary to the hypothesis that anther culture per se constitutes a general selective device for superior androgenic responses. Also, in a second experiment, anther callusing frequency was greater in the cultivar ‘Kitt’ than in any of five unique doubled-haploid lines derived from ‘Kitt’. Significant effects were also observed in the first experiment for the interactions of cultivar family X environment as well as doubled-haploid vs. cultivar X environment, although the effect of environment itself was less significant than these interactions.
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    Theoretical and applied genetics 67 (1984), S. 97-111 
    ISSN: 1432-2242
    Keywords: Genetics ; Nitrogen ; Grain crops ; Selection ; Plant breeding
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    Topics: Biology
    Notes: Summary It is necessary to increase protein productivity of grain crops to meet present and future world protein requirements. Conventional plant breeding methodology has been to select genotypes with enhanced yield or grain protein concentration. In addition to this determination of end product, we suggest measurements of a number of physiological and biochemical processes of nitrogen (N) metabolism which precede plant maturity as selection criteria for enhanced N metabolism and grain crop productivity. The measurement across the growing season of genotypic variation in components of N metabolism would constitute a physiological/biochemical selection program to be incorporated with the determination of harvestable end product. A properly designed physiological/biochemical selection program would integrate the effects of plant genotype, environment, and their interactions allowing identification of the factors limiting productivity of particular genotypes, and would also estimate end product. Our review of literature pertinent to whole plant N metabolism suggests that such a selection program initially include NO 3 - uptake, N2 fixation, N accumulation, N remobilization, seed protein synthesis, and Nitrogen Harvest Index.
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    Theoretical and applied genetics 69 (1984), S. 15-21 
    ISSN: 1432-2242
    Keywords: Genetics ; Heat tolerance ; Thyroid function ; Chickens
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    Topics: Biology
    Notes: Summary Five experiments were conducted to assess the genetic variation in thyroid function (T3, T4), body weight and heat stress survival time in chickens. Thyroxine (T4) levels were found to be elevated in response to 4 and 8 μg bovine thyroid stimulating hormone (TSH) in experiment I. In experiment II, 4 μg of TSH was injected into chickens from 30 sire families of the Athens-Canadian Randombred population. The heritability of T4 levels after TSH injection was high. In experiment III, families identified as having innate high or low T4 levels after TSH injection and a group of control birds were subjected to a heat Stressor of 50 °C for up to 240 min at six weeks of age and heat stress survival time was studied. The groups did not differ from each other in heat stress survival time. Experiment IV was similar to experiment I except triiodothyronine (T3) was also measured after TSH injection. Both T4 and T3 levels after TSH injection were moderately heritable. In experiment V birds were reared to six weeks of age and heritability calculated for body weight, T4, T3, and heat stress survival time. Heritabilities were high for body weight, moderate for T4 and heat stress survival time, and low for T3. Phenotypic correlations were significant and negative for heat stress survival time with body weight and T4, and for body weight with T3 after TSH. Significant positive correlations were found for T4 with T3 after TSH and also T4 and body weight. Analysis of genetic correlations suggested that none of the traits studied would be an adequate selection parameter for achieving heat tolerance without reducing body weight.
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    ISSN: 1432-2242
    Keywords: Genetics ; Symbiosis ; Nitrogen fixation ; Coevolution
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    Notes: Summary To determine the relationship between nodulation restriction by the Rj4 allele of soybean, rhizobitoxine-induced chlorosis, and taxonomic grouping of bradyrhizobia, 119 bradyrhizobial isolates were tested in Leonard jar culture for nodulation response and chlorosis induction. In addition to strain USDA 61, the strain originally reported as defining the Rj4 response, eight other isolates (i.e., USDA 62, 83, 94, 238, 252, 259, 260, and 340) were discovered to elicit the nodulation interdiction of the Rj4 allele. Only 16% of all the bradyrhizobial strains tested induced chlorosis, but seven of the nine strains (78%) interdicted by the Rj4 allele were chlorosis-inducing strains. Furthermore, in tests for antibiotic resistance profile, eight of the nine interdicted strains (89%) were classed in DNA homology group II. This evidence suggests that the Rj4 allele has a positive value to the host plant in shielding it from nodulation by certain chlorosis-inducing bradyrhizobia of a DNA homology group with impaired efficiency of nitrogen fixation with soybean.
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    Theoretical and applied genetics 83 (1991), S. 24-32 
    ISSN: 1432-2242
    Keywords: Genetics ; Growth curve ; Body weight ; Chickens
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    Topics: Biology
    Notes: Summary Genetic improvement in growth of poultry has traditionally proceeded via selection for body weight at a fixed age. Due to increased maintenance costs and reproductive problems of adult broiler breeders, the potential for genetic manipulation of the growth curve has been receiving increased interest. Research of both male and female progeny of a three-way diallel cross was used to investigate the inheritance of growth curve parameters. The Laird form of the Gompertz equation was used to determine growth curve parameters, and was suited to the juvenile growth data frequently collected from meat-type chickens. Growth rate exhibited significant heterosis due to both autosomes and the sex chromosomes. Age at inflection point also exhibited significant average heterosis, though only among females. Growth rate was also influenced by average line effects, as was age at inflection point. Maternal effects had no influence on growth curve parameters, while additive sex linkage was observed for growth rate. Phenotypic and genetic correlations were calculated among the growth curve parameters and suggest that specific breeding programs could alter the growth trajectory of the contemporary broiler chicken. Moderate heritabilities were observed for the growth curve parameters and support the hypothesis that the growth curve could be altered via genetic manipulation of early postnatal growth, especially during the first 14 days post-hatch.
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    ISSN: 1432-2242
    Keywords: Maize ; Restriction fragment length polymorphisms (RFLPs) ; Qualitative and quantitative inheritance ; Plant breeding ; Genetics
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    Notes: Abstract Restriction fragment length polymorphisms (RFLPs) and one morphological marker were used to investigate quantitative trait loci (QTL) for morphological and physiological traits evaluated on 150 F2∶3 maize (Zea mays L.) lines derived from the cross of elite U.S. Corn Belt inbreds Mo17 and H99. F2∶3 lines were grown in a replicated experiment and evaluated for plant and ear heights and flowering traits. QTL were identified for each trait, and genetic effects were determined. Estimated gene action for the flowering traits was predominantly overdominance. Both parents contributed toward increased values for anthesis and silk emergence. QTL for increased plant and ear heights were usually contributed by the taller parent, Mo17. Estimated gene action for these traits was mainly partial to overdominance. QTL for plant height were located in the vicinity of loci defined by alleles with qualitative effects on plant height.
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    Theoretical and applied genetics 89 (1994), S. 959-963 
    ISSN: 1432-2242
    Keywords: Sugarcane ; Polyploidy ; Genetics ; Evolution ; Breeding ; DNA markers ; Arbitrarily primed PCR ; RAPD markers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Recent work has revealed random chromosome pairing and assortment in Saccharum spontaneum L., the most widely distributed, and morphologically and cytologically variable of the species of Saccharum. This conclusion was based on the analysis of a segregating population from across between S. spontaneum ‘SES 208’ and a spontaneously-doubled haploid of itself, derived from anther culture. To determine whether polysomic inheritance is common in Saccharum and whether it is observed in a typical biparental cross, we studied chromosome pairing and assortment in 44 progeny of a cross between euploid, meiotically regular, 2n=80 forms of Saccharum officinarum ‘LA Purple’ and Saccharum robustum ‘ Mol 5829’. Papuan 2n=80 forms of S. robustum have been suggested as the immediate progenitor species for cultivated sugarcane (S. officinarum). A total of 738 loci in LA Purple and 720 loci in Mol 5829 were amplified and typed in the progeny by arbitrarily primed PCR using 45 primers. Fifty and 33 single-dose polymorphisms were identified in the S. officinarum and S. robustum genomes, respectively (χ 2 at 98%). Linkage analysis of single-dose polymorphisms in both genomes revealed linkages in repulsion and coupling phases. In the S. officinarum genome, a map hypothesis gave 7 linkage groups with 17 linked and 33 unlinked markers. Four of 13 pairwise linkages were in repulsion phase and 9 were in coupling phase. In the S. robustum genome, a map hypothesis gave 5 linkage groups, defined by 12 markers, with 21 markers unlinked, and 2 of 9 pairwise linkages were in repulsion phase. Therefore, complete polysomic inheritance was not observed in either species, suggesting that chromosomal behavior is different from that observed by linkage analysis of over 500 markers in the S. spontaneum map. Implications of this finding for evolution and breeding are discussed.
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    Theoretical and applied genetics 89 (1994), S. 313-317 
    ISSN: 1432-2242
    Keywords: Genetics ; Rice ; Phosphorousefficiency ; Diallel analysis
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    Notes: Abstract The inheritance of phosphorous (P) — deficiency tolerance in rice was investigated by a sevenparent diallel. The parent materials involved were four P-efficient (IR20, IR54, IR28, and Mahsuri), one moderately P-efficient (TN1), and two P-inefficient (IR31406333-1 and IR34686-179-1-2-1), genotypes. Relative tilering ability (RTA) under P-deficient and P-supplemented soil conditions was the parameter used in determining the tolerance level of the different genotypes. Diallel graph analysis revealed that tolerant parents have an excess of recessive genes, while moderate and susceptible parents possess more dominant genes. Genetic-component analysis suggested that both additive and dominance gene effects are involved in the inheritance of P-deficiency tolerance in rice. The trait exhibited over doiminance as confirmed by the graphical analysis. Narrow-sense heritability of the trait was moderate (0.50) and environmental effects were low. Both the general combining ability (GCA) and the specific combining ability (SCA) were significant, but GCA was more prevalent than SCA. Tolerant parents exhibited a high GCA whereas susceptibles have a very poor GCA, suggesting that tolerant parents were mostly enriched in additive genes and susceptible parents in non-additive genes. Crosses involving two high general combiners showed low SCA effects whereas crosses between poor general combiners manifested highly-significant SCA values.
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    Theoretical and applied genetics 50 (1977), S. 41-46 
    ISSN: 1432-2242
    Keywords: Barley ; Gum Content ; Genetics ; Genotype ; Environment Interaction
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    Topics: Biology
    Notes: Summary A diallel cross analysis of gum content in barley (Hordeum vulgare) was made using six cultivars of two-rowed spring barley as parents. A Jinks-Hayman analysis of F2 progeny means showed that gum content was controlled by a simple additive-dominance genetic system and that low gum content was strongly dominant. The analysis suggested that gum content was principally controlled by two or three genes showing a high degree of dominance. Some genotype-environment interaction was detected in a comparison between the F2 and F3 generations which were grown in different years and locations. However, the character was found to be highly heritable both within and between generations, suggesting that the selection and breeding of barleys of reduced gum content should not be difficult.
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    Theoretical and applied genetics 67 (1983), S. 67-73 
    ISSN: 1432-2242
    Keywords: Somaclonal variation ; Genetics ; Oryza sativa L. ; Rice improvement
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    Topics: Biology
    Notes: Summary The inheritance and variations of some traits of more than 2,000 somatic cell derived plants of rice (Oryza sativa L.) were investigated in the second and third generations (T2 and T3) of regenerated plants (somaclones). The percentages of multiploids occurring in somaclones ranged from 0–13.3 in nine varieties (or hybrids) of ‘Hsien’ (indica) group, but no multiploid was found in nine varieties (or hybrid) of ‘Keng’ (japonica) group. A dwarf mutant with the height of only 20 cm was isolated in the T2 of ‘Tai-Zhong-Yu 39’. Genetic analysis indicated that it was controlled by a single recessive gene. The frequencies of chlorophyll mutations probably controlled by cytoplasmic genes decreased gradually with the advance of generations. The variations of five quantitative traits — plant height, grain weight, etc. — in 950 T2 pedigree lines of four varieties were also studied. Only 24.4% of the lines were normal in all the traits studied. Variation frequencies of different traits were from 11.5% to 39.5%. And there was an obvious tendency for the plant height to become shorter, number of productive tillers to increase and 1,000 grain weight to be lighter, whatever the variety studied. Traits were uniform within each of more than 90% of all T2 lines studied. What is more interesting, variations phenotyped in T2 proved to breed true. Causes of somaclonal variations are discussed, as well as their potentials in breeding.
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    Theoretical and applied genetics 82 (1991), S. 761-764 
    ISSN: 1432-2242
    Keywords: Rye ; Male sterility ; Genetics ; Gene location ; Trisomies
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    Notes: Summary The genetics and relationships between the genes in rye located in the nucleus and cytoplasm of the male sterility of the G-type were investigated. A factor inducing male sterility was found in the cytoplasms or rye cv Schlägler alt and rye cv Norddeutscher Champagner. Monogenic inheritance was observed in linkage tests. Using primary trisomies of rye cv Esto, the nuclear gene ms1 was found to be located on chromosome 4R. Modifying genes, probably masked in normal cytoplasm but expressed in male-sterility-inducing cytoplasm together with gene ms1, were located on chromosomes 3R (ms2) and 6R (ms3). Mono-, di-, and trigenic inheritance types were found in backcross progenies of trisomies.
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    Theoretical and applied genetics 86 (1993), S. 333-338 
    ISSN: 1432-2242
    Keywords: Genetics ; Rice ; Salinity ; Tolerance ; Na-Kratio ; Diallel
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The genetics of salinity tolerance in rice was investigated by a nine-parent complete diallel including reciprocals. Test materials involved susceptible (IR28, IR29, and MI-48), moderately tolerant (IR4595-4-1-13, IR9884-54-3-1E-P1, and IR10206-29-2-1), and tolerant (“Nona Bokra”, “Pokkali”, and SR26B) parents. Twoweek-old seedlings were grown in a salinized (EC = 12 dS/m) culture solution for 19 days under controlled conditions in the IRRI phytotron. Typical characteristics of salinity tolerance in rice were found to be Na+ exclusion and an increased absorption of K+ to maintain a good Na-K balance in the shoot. Genetic component analysis (GCA) revealed that a low Na-K ratio is governed by both additive and dominance gene effects. The trait exhibited overdominance, and two groups of genes were detected. Environmental effects were large, and the heritability of the trait was low. Our findings suggest that when breeding for salt tolerance, selection must be done in a later generation and under controlled conditions in order to minimize environmental effects. Modified bulk and single-seed descent would be the suitable breeding methods. Combining ability analysis revealed that both GCA and specific combining ability (SCA) effects were important in the genetics of salt tolerance. Moderately tolerant parents — e.g., IR4595-4-1-13 and IR9884-54-3-1E-P1 — were the best general combiners. Most of the best combinations had susceptible parents crossed either to moderate or tolerant parents. The presence of reciprocal effects among crosses necessitates the use of susceptible parents as males in hybridization programs. Large heterotic effects suggest the potential of hybrid rice for salt-affected lands.
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    Theoretical and applied genetics 88 (1994), S. 754-758 
    ISSN: 1432-2242
    Keywords: Potato breeding ; Potato leaf roll virus ; Virus resistance ; Major gene resistance ; Genetics
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    Notes: Abstract The concentration of potato leaf roll virus (PLRV), as measured by a quantitative enzyme-linked immunosorbent assay, in the foliage of potato plants (Solanum tuberosum) of cv ‘Maris Piper’ with secondary infection was 2900 ng/g leaf, whereas in clones G7445(1) and G7032(5) it was 180 ng/g leaf and 120 ng/g leaf, respectively. To examine the genetic control of resistance to PLRV multiplication, reciprocal crosses were made between the susceptible cultivar ‘Maris Piper’ and the two resistant clones, and the three parents were selfed. Seedling progenies of these families were grown to generate tubers of individual genotypes (clones). Clonally propagated plants were graft-inoculated, and their daughter tubers were collected and used to grow plants with secondary infection in which PLRV concentration was estimated. The expression of resistance to PLRV multiplication had a bimodal distribution in progenies from crosses between ‘Maris Piper’ and either resistant clone, and also in progeny from selfing the resistant parents, with genotypes segregating into high and low virus titre groups. Only the progeny obtained from selfing ‘Maris Piper’ did not segregate, all genotypes being susceptible to PLRV multiplication. The pattern of segregation obtained from these progenies fits more closely with the genetical hypothesis that resistance to PLRV multiplication is controlled by two unlinked dominant complementary genes, both of which are required for resistance, than with the simpler hypothesis that resistance is conferred by a single dominant gene, as published previously.
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    Theoretical and applied genetics 51 (1977), S. 35-39 
    ISSN: 1432-2242
    Keywords: Parameters ; Genetics ; Precision ; Simulation
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    Topics: Biology
    Notes: Summary Approximate standard errors of genetic parameter estimates were obtained using a simulation technique and approximation formulae for a simple statistical model. The similarity of the corresponding estimates of standard errors from the two methods indicated that the simulation technique may be useful for estimating the precision of genetic parameter estimates for complex models or unbalanced population structures where approxi mation formulae do not apply. The method of generating simulation populations in the computer is outlined, and a technique of setting approximate confidence limits to heritability estimates is described.
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    Theoretical and applied genetics 55 (1979), S. 225-229 
    ISSN: 1432-2242
    Keywords: Generation means ; Matrices ; Genetics ; Models
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Gene action and interaction have been defined in the literature by the use of a variety of notations (Mather 1949; Hayman 1954, 1955, 1957; Jinks 1954; Kempthorne 1954, 1955). This leads to unnecessary complications in understanding the subject. This paper provides a simple convenient way of translating one parameterization into another and illustrates the simple linear relationship between them. The various notations are written in matrix form by the use of a specification matrix. This provides a convenient compact method of presentation of the relevant Equations. The linear relationship between the genetic parameters enables these to be estimated in the most convenient way and then converted to other parameters for the purposes of comparison. The generation means Equations of Hayman (1958) are derived using the matrix formulation as an illustration of the use of the specification matrix.
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    Theoretical and applied genetics 57 (1980), S. 91-95 
    ISSN: 1432-2242
    Keywords: Cell culture ; Picloram-tolerance ; Genetics ; Uptake studies ; Nicotiana tabacum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A genetic and preliminary biochemical analysis has been performed on four picloram-tolerant mutants of Nicotiana tabacum that were isolated from cell cultures. The four mutations define three distinct linkage groups. Mutant seedlings incorporate radioactively labeled picloram normally and do not modify or degrade the herbicide in a manner that alters its solubility characteristics.
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  • 39
    ISSN: 1432-2242
    Keywords: Genetics ; Loci ; Powdery mildew ; Prolamin ; Recombination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The linkage relationship among the loci Hor1, Hor2, Ml-k and Ml-a on the short arm of chromosome 5 was studied by progeny testing the F2 generation of two crosses. The loci Hor1 and Hor2 code for polypeptides of the storage protein hordein (prolamin) and the loci Ml-k and Ml-a determine the resistance reaction with some powdery mildew fungi cultures. The order of the loci is Ml-k, Hor1, Ml-a, and Hor2, the first named being nearest the centromere. The recombination percentage between Hor1 and Hor2 was determined in the F1 and F2 generations in both crosses, the combined estimate being 7.4±0.9 per cent. The recombination percentage estimated between Ml-k and Hor1 was 4.0±1.3, between Hor1 and Ml-a, 5.3±1.1, and between Ml-a and Hor2, 6.1±1.2. The estimates involving the Ml- loci were all probably a little too high.
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    Theoretical and applied genetics 60 (1981), S. 229-236 
    ISSN: 1432-2242
    Keywords: Glutenin ; Triticum ; Genetics ; SDS ; Polyacrylamide-gel-electrophoresis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The high-molecular-weight (HMW) subunits of glutenin from about 185 varieties were fractionated by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). About 20 different, major subunits were distinguished by this technique although each variety contained, with only a few exceptions, between 3 and 5 subunits. Further inter-varietal substitution lines to those already described (Payne et al. 1980) were analysed and the results indicate that all the HMW subunits are controlled by the homoeologous group 1 chromosomes. All hexaploid varieties studied except ‘NapHal’ contained two major subunits controlled by chromosome 1D. Their genes were shown to be tightly linked genetically for only four different types of banding patterns were observed. The nominal molecular weights determined after fractionation in 10% polyacrylamide gels were between 110,000 and 115,000 for the larger of the two subunits and between 82,000 and 84,000 for the smaller. One quarter of the varieties contained only one major HMW subunit controlled by chromosome 1B whereas the rest had two. The chromosome 1B subunits were the most varied and nine different banding patterns were detected. All the subunits had mobilities which were intermediate between those of the two chromosome 1D-controlled subunits. Only two types of HMW subunit controlled by chromosome 1A were detected in all the varieties examined; a single variety never contained both of these subunits and 40% of varieties contained neither. The chromosome 1A-controlled subunits had slightly slower mobilities in 10% gels than the largest HMW subunit controlled by chromosome 1D. About 100 single grains were analysed from each of five different crosses of the type (F1 of variety A × variety B) × variety C. The results indicate that the genes on chromosome 1B which control the synthesis of subunits 6, 7, 13, 14 and 17 are allelic, as are the genes of the chromosome 1A-controlled subunits, 1 and 2.
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    Theoretical and applied genetics 60 (1981), S. 265-268 
    ISSN: 1432-2242
    Keywords: Agrocybe ; Genetics ; Fruiting ; Biomass
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In the edible white rot fungus Agrocybe aegerita the threshold from mycelial growth to fruit body formation is under control of a single gene in both monokaryons and dikaryons. The allele su opens the pathway for fruiting and allows the subsequent expression of the fruiter genes fi+ (fruit body initials) and fb + (fruit bodies). Its allele, su +, suppresses monokaryotic fruiting completely and restricts dikaryotic fruiting drastically. The detection of this threshold gene su +/su and its action and interactions has practical implication in that an opportunity for concerted breeding is created. First results indicate that the fruiter genes are involved in two essential parameters of productivity. Both time of fruiting and biomass production depend on the two fruiter genes fi + and fb +. Comparable results obtained with two other basidiomycetes suggest that the genetic control of fruiting in Agrocybe aegerita is a general mechanism which may be made use of in breeding work with other basidiomycetes of economic value.
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    Theoretical and applied genetics 62 (1982), S. 97-102 
    ISSN: 1432-2242
    Keywords: Guide dogs ; Behaviour ; Genetics
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    Topics: Biology
    Notes: Summary Many dogs are found to be unsuitable for training as guide dogs for the blind. Consequently the Royal Guide Dogs for the Blind Association of Australia has embarked on a breeding program to produce a strain of labrador dogs which is suitable for guide dog training. The most common reasons for rejecting dogs are fearfulness, dog distraction, excitability, health and physical reasons and hip dysplasia. The selection program seems to have been successful in improving the success rate mainly by lowering fearfulness, but there has not been a continuing improvement. This is probably due to continual introduction of dogs from other populations into the breeding program. Males suffer from a higher rejection rate due to dog distraction and a lower rejection rate due to fearfulness and excitability than females, so that there is little sex difference in overall success rate. The heritability of success (0.44) is high enough to predict further progress from selection, again mainly against fearfulness. Variation in environment prior to 6 weeks of age, in age when dogs were placed into a private home and in age when males were castrated, had little effect on the success rate.
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  • 43
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    Theoretical and applied genetics 62 (1982), S. 233-239 
    ISSN: 1432-2242
    Keywords: Hordeum vulgare ; Haploids ; Androgenetic responsiveness ; Genetics
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    Topics: Biology
    Notes: Summary Anthers of 55 different spring barley (Hordeum vulgare) hybrids and four varieties were cultured in vitro. Microspores of each hybrid gave rise to calluses and subsequently plantlets, from all hybrids, except one. As criteria of microspore responsiveness, callus formation and plant regeneration frequencies were studied in detail. Large differences with regard to these criteria were found, which were traced back to the genotype of the anther donor plant. Callus formation varied between 3.3 and 73.2 per 1,000 anthers plated, whereas green plant regeneration ranged from 0 to 12.7 per 1,000 anthers cultured. Comparisons of microspore regeneration frequencies of hybrids and their parents indicated that culture responsiveness is a heritable, complex character involving at least two different and separately inherited mechanisms: 1) the ability of microspores within anthers to divide and give rise to calluses and subsequently 2) the ability of calluses for morphogenesis, to yield green or albino plants. Because it is heritable, anther culture responsiveness can be transferred to breeding material which is initially non-responsive. This genetic way of improving success in androgenetic haploid production appears to be more realistic than the search for optimum culture conditions.
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    Theoretical and applied genetics 67 (1983), S. 53-58 
    ISSN: 1432-2242
    Keywords: Aegilops umbellulata ; Genetics ; Lectin ; Triticum aestivum
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    Topics: Biology
    Notes: Summary Each of the three genomes in hexaploid wheat controls the expression of a specific lectin in the embryo. The chromosomes which control their synthesis were determined using nullisomic-tetrasomic and inter-varietal chromosome substitution lines of ‘Chinese Spring’. All three wheat lectins were shown to be controlled by the homoeologous group 1 chromosomes. Using ditelosomic lines of ‘Chinese Spring’ the lectin genes could be localized on the long arms of chromosomes 1A and 1D. Inter-specific addition and substitution lines of Aegilops umbellulata chromosomes to ‘Chinese Spring’ indicated that chromosome 1U, which is homoeologous to the group 1 chromosomes of wheat, controls lectin synthesis.
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    Theoretical and applied genetics 53 (1978), S. 29-31 
    ISSN: 1432-2242
    Keywords: Citrullus lanatus ; Seed-coat colour ; Genetics
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    Topics: Biology
    Notes: Summary Intervarietal crosses in watermelon, Citrullus lanatus (Thunb.) Mansf., involving six parents with black (J18-1 and J 75), brown (J56-1 and N.H. Midget), red (Bykovski-199) or light cream (Red Nectar) seed-coat colour were made. Parents, F1, F2 and backcross populations were evaluated for their phenotypic expressions with regard to the seed-coat colours involved. Black colour was monogenically dominant over brown light cream and red colour of seed-coat separately or independently. Red colour was dominant over light cream colour of seed-coat by a single pair of genes. The light cream colour was recessive to the brown seed-coat colour of watermelon where a single pair of genes was involved.
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    Theoretical and applied genetics 52 (1978), S. 227-231 
    ISSN: 1432-2242
    Keywords: Poultry ; Genetics ; Index selection ; Egg mass
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Predicted and realized responses in a single generation of mass selection for an index and for its component traits were compared. The index included the log transformed traits determining egg mass in chickens to 40 weeks of age (days tested from sexual maturity, egg weight, rate of lay). The index was restricted to allow no increase in log days tested. Other traits measured were egg mass, age at first egg, egg weight, rate of lay, number of eggs and body weight. When averaged over replicates, realized and predicted responses were in close agreement for index values and for the component traits. Significant corresponding correlated responses were obtained for egg mass and weight. The restricted trait, log days tested, and the correlated trait age at first egg did not change. Egg mass was increased solely through change in egg weight.
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    Theoretical and applied genetics 56 (1980), S. 5-9 
    ISSN: 1432-2242
    Keywords: Genetics ; Poultry ; Family selection ; Individual selection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Responses to single trait selection on individual phenotype and sire-family mean phenotype for survivor's egg weight and rate of lay were measured for a single generation in 13 replicates. Each replicate-selection criterion-trait subclass consisted of eight sire families or 72 females measured and was reproduced from the best 25% of the families or individuals. The realized heritability of egg weight was 0.39 and that of rate of lay was 0.31, both of which were significantly greater than zero but not significantly different from the predicted values based on halfsib correlations in the base population. The standardized response to sire-family selection was less than the response to individual selection for both traits and the difference was significant for rate of lay (0.10; 0.31) but not for egg weight (0.22; 0.39). The predicted responses to sire-family selection were less than those for individual selection for both traits, and the observed responses to sire-family selection were not significantly different from the predicted values for either trait. These experimental results do not disagree with the theoretical expectations of the relative efficiencies of individual and sire-family selection.
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    Theoretical and applied genetics 58 (1980), S. 113-120 
    ISSN: 1432-2242
    Keywords: Glutenin ; Triticum ; Genetics ; SDS-polyacrylamide ; Gel-electrophoresis
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    Topics: Biology
    Notes: Summary The electrophoretic mobilities of the high-molecular-weight (HMW) subunits of glutenin from 7 varieties were compared by polyacrylamide-gel electrophoresis in the presence of sodium dodecyl sulphate (SDS). In total, 12 subunits were clearly resolved and they had nominal molecular weights of between 95,000 and 140,000. The chromosomes which control their synthesis were determined using monosomic lines and inter-varietal substitution lines. All subunits were shown to be controlled by the homoeologous group 1 chromosomes. Each variety contains between 3 and 5 HMW subunits; two are under the control of the 1D chromosome, 1 or 2 are controlled by chromosome 1B and 0 or 1 by chromosome 1A. The segregation of two 1D-controlled subunits of similar electrophoretic mobilities were analysed in the F2 progeny of crosses between ‘Chinese Spring’ and ‘Holdfast’. The results suggest that the genes which code for the two proteins are allelic.
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  • 49
    ISSN: 1432-2242
    Keywords: Beta vulgaris ; Sugar beet ; Isozymes ; Genetics ; Linkage ; Pollen fertility restorer
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    Topics: Biology
    Notes: Summary The NADP-specific malate dehydrogenase isozymes were controlled by multiple gene systems. Three genes coding for dimeric enzymes segregated in a dependent fashion (NADP-Mdh 1, NADP-Mdh 2, NADP-Mdh 3). A fourth gene (NADP-Mdh 4), also coded for dimers, but was not polymorphic in B. vulgaris. A fifth gene (NADP-Me 1) coded for enzymes active as monomers. Two genes were found to control the main zone of NAD-specific malate dehydrogenase: one coded for dimers (Mdh 1), while a second (Mdh 2) was not polymorphic in the assessions studied. 6-P-Gluconate dehydrogenase was not polymorphic in B. vulgaris; the two types detected on SGE1 electrophoresis were due to developmental expression of the different systems. No genetical segregations could be detected in progeny of crosses of the distinct phenotypes. A shikimate dehydrogenase gene (Skdh 1) that coded for monomers was identified. The diaphorase system was rather complex, but one gene (Dia 1) coding for monomeric enzymes could be identified. Aconitase was found to be controlled by two independent genes (Aco 1, Aco 2), both polymorphic and coding for proteins active as monomers. Tight linkage was found between the genes NADP-Mdh 1, NADP-Mdh 2 and NADP-Mdh 3. Linkage was also found between a pollen fertility restorer (Z) and the Mdh 1 gene. The identification of linkage with Aco 1 needs further investigation. R segregated independently from Mdh 1, Aco 1 and Dia 1. Independent segregations were scored for isozyme genes Pgm 2, Icd 1, Ak 1, Gpi 1, Aco 1 and Dia 1.
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    Theoretical and applied genetics 81 (1991), S. 50-58 
    ISSN: 1432-2242
    Keywords: Vicia faba ; Legumin ; Vicilin ; Structure ; Genetics
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    Topics: Biology
    Notes: Summary Legumin and vicilin were purified from seeds of Vicia faba L. var. Scuro, characterized in different electrophoretic systems, and used to produce polyclonal antibodies in rabbits. Two-dimensional electrophoretic studies showed a wide range of heterogeneity in the subunits of both legumin and vicilin. Legumin was found to be composed of 29 disulphide-linked subunit pairs with different molecular weight and/or isoelectric point. Western blot analysis of legumin of several mutants revealed molecular polymorphism based on a corresponding gene family. Three different α-major legumin patterns were found, and inheritance studies showed that the 34.3-kD legumin polypeptide is the product of one locus, Lg-1α, which is the first legumin genetic locus described in Vicia faba. Vicilin was found to be composed of as many as 59 subunits distributed in a molecular weight range of 65.7 to 42.8 kD (major polypeptides) and 37.2 to 15.2 kD (minor polypeptides), with different isoelectric points. A model is proposed that explains the possible formation of the minor subunits and the major subunits of 48.2 and 46 kD molecular weight (MW) from proteolytic cleavages and/or glycosilation of precursor polypeptides. Ten different vicilin electrophoretic patterns were observed among the analyzed accessions, which showed large molecular polymorphism that proved to be under genetic control.
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    Theoretical and applied genetics 82 (1991), S. 771-776 
    ISSN: 1432-2242
    Keywords: Secale cereale ; RFLP ; α-Amylase ; Genetics ; Isozymes
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    Topics: Biology
    Notes: Summary Rye α-Amy1, α-Amy2, and α-Amy3 genes were studied in the cross between inbred lines using wheat α-amylase cDNA probes. The α-Amy1 and α-Amy2 probes uncovered considerable restriction fragment length polymorphism, whereas the α-Amy3 region was much more conserved. The numbers of restriction fragments found and the F2 segregation data suggest that there are three α-Amy1 genes, two or three α-Amy2 genes, and three α-Amy3 genes in rye. These conclusions were supported by a simultaneous study of α-amylase isozyme polymorphism. The F2 data showed the three individual α-Amy1 genes to span a distance of 3cM at the locus on chromosome 6RL. The genes were mapped relative to other RFLP markers on 6RL. On chromosome 7RL two α-Amy2 genes were shown to be separated by 5 cM. Linkage data within α-Amy3 on 5RL were not obtained since RFLP could be detected at only one of the genes.
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    Theoretical and applied genetics 84 (1992), S. 714-719 
    ISSN: 1432-2242
    Keywords: Wheat ; Salinity ; Genetics
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    Topics: Biology
    Notes: Summary Accessions of Triticum tauschii (Coss.) Schmal. (D genome donor to hexaploid wheat) vary in salt tolerance and in the rate that Na+ accumulates in leaves. The aim of this study was to determine whether these differences in salt tolerance and leaf Na+ concentration would be expressed in hexaploid wheat. Synthetic hexaploids were produced from five T. tauschii accessions varying in salt tolerance and two salt-sensitive T. turgidum cultivars. The degree of salt tolerance of the hexaploids was evaluated as the grain yield per plant in 150 mol m-3 NaCl relative to grain yield in 1 mol m-3 NaCl (control). Sodium concentration in leaf 5 was measured after the leaf was fully expanded. The salt tolerance of the genotypes correlated negatively with the concentration of Na+ in leaf 5. The salt tolerance of the synthetic hexaploids was greater than the tetraploid parents primarily due to the maintenance of kernel weight under saline conditions. Synthetic hexaploids varied in salt tolerance with the source of their D genome which demonstrates that genes for salt tolerance from the diploid are expressed at the hexaploid level.
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  • 53
    ISSN: 1432-2242
    Keywords: Genetics ; Disease ; Mapping ; Breeding
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    Topics: Biology
    Notes: Abstract Molecular markers at 103 loci were used to identify the location of quantitative sources of resistance to Exserohilum turcicum in 150 F2∶3 lines of a B52/Mo17 maize population. Host-plant response was measured in terms of the average number of lesions per leaf, the average percent leaf tissue diseased (severity), and the average size of lesions. The location of quantitative trait loci were compared with three loci having known qualitative effects, namely Ht1, Ht2 and bx1. Chromosomal regions containing the Ht1 and Ht2 loci showed a small contribution in determining lesion size, even though alleles with dominant, qualitative effects at these loci have never been reported in either inbred parent. Similar effects were not observed for the number of lesions or for disease severity. Likewise, some contribution was observed for chromosomal regions encompassing the bx1 locus in determining lesion size but not the number of lesions or disease severity. Overall the contribution of loci in the vicinity of Ht1, Ht2 and bx1 was small relative to variation attributable to loci with quantitative effects identified in this study. Molecular-marker-facilitated mapping concurred with previous reciprocal translocation mapping studies on the importance of chromosomes 3, 5 and 7, despite the fact that these studies utilized diverse sources of resistant germplasm.
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  • 54
    ISSN: 1432-2242
    Keywords: Breeding ; Helminthosporium turcicum ; RFLP ; QTLs ; Disease-resistance ; Genetics
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    Notes: Abstract RFLPs were used to investigate components of host-plant response to Exserohilum turcicum in 150 unselected F2∶3 lines of a B52/Mo17 maize population. Following inoculation with spore suspensions of the pathogen (race 0), components of disease development were measured and then quantitative trait mapping was performed to identify the location and effects of quantitative trait loci (QTLs) determining host-plant response. Components of interest were the average number of lesions per leaf, the average percent leaf tissue diseased (severity) and the average size of lesions (cm2). Based on a LOD threshold of 2.31 (P〈0.05), the number of lesions appears to be associated with QTLs on chromosomes 1S, 3L, 5S. Severity was associated with analogous regions and, in addition, QTLs on chromosomes 7L and 8L. Most QTLs, for either of these two components, involve additive gene action and partial dominance or overdominance. In contrast, lesion size was associated with QTLs on chromosomes 7L and 5L; recessive gene action may be involved at 7L.
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  • 55
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    Keywords: Genetics ; Disease resistance ; Monocots
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    Notes: Abstract An F2 oat population was produced by crossing the diploid (n=7) species Avena strigosa (CI 3815) with A. wiestii (CI 1994), resistant and susceptible, respectively, to 40 isolates of Puccinia coronata, the causal agent of crown rust. Eighty-eight F2 individuals were used to construct an RFLP linkage map representing the A genome of cultivated hexaploid oat. Two hundred and eight RFLP loci have been placed into 10 linkage groups. This map covers 2416 cM, with an average of 12 cM between RFLP loci. Eighty-eight F3 lines, derived from F2 individuals used to construct the map, were screened for resistance to 9 isolates of P. coronata. One locus, Pca, was found to confer a dominant resistance phenotype to isolates 203, 258, 263, 264B, 290, 298, 325A, and 345. Pca also conferred resistance to isolate 276; however, an unlinked second gene may also be involved.
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    Behavioral ecology and sociobiology 34 (1994), S. 117-409 
    ISSN: 1432-0762
    Keywords: Social insects ; Apis mellifera ; Division of labor ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Variability exists among worker honey bees for components of division of labor. These components are of two types, those that affect foraging behavior and those that affect life-history characteristics of workers. Variable foraging behavior components are: the probability that foraging workers collect (1) pollen only; (2) nectar only; and (3) pollen and nectar on the same trip. Life history components are: (1) the age the workers initiate foraging behavior; (2) the length of the foraging life of a worker; and (3) worker length of life. We show how these components may interact to change the social organization of honey bee colonies and the lifetime foraging productivity of individual workers. Selection acting on foraging behavior components may result in changes in the proportion of workers collecting pollen and nectar. Selection acting on life-history components may affect the size of the foraging population and the distribution of workers between within nest and foraging activities. We suggest that these components define possible sociogenic “pathways” through which colony-level natural selection can change social organization. These pathways may be analogous to developmental pathways in the morphogenesis of individual organisms because small changes in behavioral or life history components of individual workers may lead to major changes in the organizational structure of colonies.
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    Behavioral ecology and sociobiology 35 (1994), S. 99-107 
    ISSN: 1432-0762
    Keywords: Key words Apis mellifera ; Genetics ; Drone production ; Allozymes ; Reproductive conflict
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    Topics: Biology
    Notes: Abstract Previously we reported that there are subfamily differences in drone production in queenless honey bee colonies, but these biases are not always explained by subfamily differences in oviposition behavior. Here we determine whether these puzzling results are best explained by either inadequate sampling of the laying worker population or reproductive conflict among workers resulting in differential treatment of eggs and larvae. Using colonies composed of workers from electrophoretically distinct subfamilies, we collected samples of adult bees engaged in the following behavior: “true” egg laying, “false” egg laying, indeterminate egg laying, egg cannibalism, or nursing (contact with larvae). We also collected samples of drone brood at four different ages: 0 to 2.5-h-old eggs, 0 to 24-h-old eggs, 3 to 8-day-old larvae, and 9 to 14-day-old larvae and pupae. Allozyme analyses revealed significant subfamily differences in the likelihood of exhibiting egg laying, egg cannibalism, and nursing behavior, as well as significant subfamily differences in drone production. There were no subfamily differences among the different types of laying workers collected from each colony, suggesting that discrepancies between subfamily biases in egg-laying behavior and drone production are not due to inadequate sampling of the laying worker population. Subfamily biases in drone brood production within a colony changed significantly with brood age. Laying workers had significantly more developed ovaries than either egg cannibals or nurses, establishing a physiological correlate for the observed behavioral genetic differences. These results suggest there is reproductive conflict among subfamilies and individuals within queenless colonies of honey bees. The implications of these results for the evolution of reproductive conflict, in both queenright and queenless contexts, are discussed.
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    Behavioral ecology and sociobiology 34 (1994), S. 125-137 
    ISSN: 1432-0762
    Keywords: Social insects ; Apis mellifera ; Division of labor ; Genetics ; Nepotism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Three experiments were performed to determine whether brood care in honey bee colonies is influenced by colony genetic structure and by social context. In experiment 1, there were significant genotypic biases in the relative likelihood of rearing queens or workers, based on observations of individually labeled workers of known age belonging to two visually distinguishable subfamilies. In experiment 2, no genotypic biases in the relative likelihood of rearing drones or workers was detected, in the same colonies that were used in experiment 1. In experiment 3, there again were significant genotypic differences in the likelihood of rearing queens or workers, based on electrophoretic analyses of workers from a set of colonies with allozyme subfamily markers. There also was an overall significant trend for colonies to show greater subfamily differences in queen rearing when the queens were sisters (half- and super-sisters) rather than unrelated, but these differences were not consistent from trial to trial for some colonies. Results of experiments 1 and 3 demonstrate genotypic differences in queen rearing, which has been reported previously based on more limited behavioral observations. Results from all three experiments suggest that genotypic differences in brood care are influenced by social context and may be more pronounced when workers have a theoretical opportunity to practice nepotism. Finally, we failed to detect persistent interindividual differences in bees from either subfamily in the tendency to rear queen brood, using two different statistical tests. This indicates that the probability of queen rearing was influenced by genotypic differences but not by the effect of prior queen-rearing experience. These results suggest that subfamilies within a colony can specialize on a particular task, such as queen rearing, without individual workers performing that task for extended periods of time.
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    Behavioral ecology and sociobiology 35 (1994), S. 99-107 
    ISSN: 1432-0762
    Keywords: Apis mellifera ; Genetics ; Drone production ; Allozymes ; Reproductive conflict
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    Topics: Biology
    Notes: Abstract Previously we reported that there are subfamily differences in drone production in queenless honey bee colonies, but these biases are not always explained by subfamily differences in oviposition behavior. Here we determine whether these puzzling results are best explained by either inadequate sampling of the laying worker population or reproductive conflict among workers resulting in differential treatment of eggs and larvae. Using colonies composed of workers from electrophoretically distinct subfamilies, we collected samples of adult bees engaged in the following behavior: “true” egg laying, “false” egg laying, indeterminate egg laying, egg cannibalism, or nursing (contact with larvae). We also collected samples of drone brood at four different ages: 0 to 2.5-h-old eggs, 0 to 24-h-old eggs, 3 to 8-day-old larvae, and 9 to 14-day-old larvae and pupae. Allozyme analyses revealed significant subfamily differences in the likelihood of exhibiting egg laying, egg cannibalism, and nursing behavior, as well as significant subfamily differences in drone production. There were no subfamily differences among the different types of laying workers collected from each colony, suggesting that discrepancies between subfamily biases in egg-laying behavior and drone production are not due to inadequate sampling of the laying worker population. Subfamily biases in drone brood production within a colony changed significantly with brood age. Laying workers had significantly more developed ovaries than either egg cannibals or nurses, establishing a physiological correlate for the observed behavioral genetic differences. These results suggest there is reproductive conflict among subfamilies and individuals within queenless colonies of honey bees. The implications of these results for the evolution of reproductive conflict, in both queenright and queenless contexts, are discussed.
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    Protoplasma 176 (1993), S. 53-63 
    ISSN: 1615-6102
    Keywords: Acetabularia acetabulum ; Gamete release ; Mating efficiency ; Mating physiology ; Gamete half-life ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have improved zygote recovery 11–1,000 fold by optimizing the physiology of gamete release and mating inAcetabularia acetabulum. Gamete release was affected by agar purity, concentration, and volume/gametangial pair. Cold pre-treatment of gametangia (14–30 d at 10°C in the dark) synchronized subsequent gamete release at 21°C in the light. Cold pre-treatment was nearly twice as effective in synchronizing subsequent gamete release when intact, gametangia-bearing caps rather than isolated gametangia were pretreated. Synchronizing gamete release doubled mating efficiency. In a wild-type laboratory strain ofA. acetabulum, there were 1,561±207 gametes/gametangium which had half-lives of 14.5 d in 0.1% seawater-agar. We recovered 48–93% of the expected numbers of zygotes from a mass mating of 8 to 1,226 gametangia and 11–128% of the expected numbers of zygotes from mating single gametangial pairs: the large range in the calculated mating efficiency may be attributable to the variation in the numbers of gametes made per gametangium. Zygote recovery from single gametangial pairs was highly dependent on the volume of mating matrix. In addition, most zygotes recovered were unattached to any other zygotes in the subsequent generation (〉 95% single cells from matings of 1–500 gametangial pairs). Our improvements in mating conditions and zygote recovery (1) have facilitated cell manipulation and culture ofA. acetabulum in the laboratory; and (2) have made controlled crosses for selection and genetic analysis of mutants feasible. These advances have removed a major barrier to genetic analysis of development inAcetabularia.
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    Plant ecology 50 (1982), S. 23-42 
    ISSN: 1573-5052
    Keywords: Beech ; Beechwoods ; Bioclimatology ; Fagus ; Genetics ; Mediterranean region ; Vegetation structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The study area is at the southern limit of the beech area, between the rivers Rhône in France and Ebro in Spain. From an analysis of the occurrence of beechwoods in this region and the pluviometric climate, it appears that part of the beechwood is found in a dry climate, which is still mediterranean. This argument seems sufficient to justify the existence of a ‘mediterranean’ beechwood, at least on a climatic level. Beechwood when occurring in a dry climate has special characteristics: - The development of the wood differs with the climate. Young beeches need shadow in a dry climate; they can grow in full light in a moist climate. - The floristic composition is different. - The understorey of dry woods is less structured than that of moist woods. - The genetic structure as measured in the enzymatic system Px1 is polymorphic in the dry and monomorphic in the moist conditions studied. It would be interesting to verify if the characters noted in a dry mediterranean climate are also present in dry atlantic or continental beechwoods. Since the mediterranean climate is drier and more unfavorable to beech than other climates, the particular characters of ‘dry’ beechwoods will be more pronounced near the Mediterranean.
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    Biology and philosophy 5 (1990), S. 349-371 
    ISSN: 1572-8404
    Keywords: Genetics ; gene structure ; hereditary unit
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    Topics: Biology , Philosophy
    Notes: Abstract Definitions of the term ‘gene’ typically superimpose molecular genetics onto Mendelism. What emerges are persistent attempts to regard the gene as a ‘unit’ of structure and/or function, language that creates multiple meanings for the term and fails to acknowledge the diversity of gene architecture. I argue that coherence at the molecular level requires abandonment of the classical unit concept and recognition that a gene is constructed from an assemblage of domains. Hence, a domain set (1) conforms more closely to empirical evidence for genetic organization of DNA regions capable of transcription and (2) has ontological properties lacking in the traditional unit definition.
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  • 63
    ISSN: 1617-4623
    Keywords: Gene regulation ; Ribozyme ; npt-gene ; Transgenic tobacco ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A chimeric gene encoding a ribozyme under the control of the cauliflower mosaic virus (CaMV) 35S promoter was introduced into transgenic tobacco plants. In vivo activity of this ribozyme, which was designed to cleave npt mRNA, was previously demonstrated by transient expression assays in plant protoplasts. The ribozyme gene was transferred into transgenic tobacco plants expressing an rbcS-npt chimeric gene as an indicator. Five double transformants out of sixteen exhibited a reduction in the amount of active NPT enzyme. To measure the amount of ribozyme produced, in the absence of its target, the ribozyme and target genes were separated by genetic segregation. The steady-state concentrations of ribozyme and target RNA were shown to be similar in the resulting single transformants. Direct evidence for a correlation between reduced npt gene expression and ribozyme expression was provided by crossing a plant containing only the ribozyme gene with a transgenic plant expressing the npt gene under control of the 35S promoter, i.e. the same promoter used to direct ribozyme expression. The expression of npt was reduced in all progeny containing both transgenes. Both steady-state levels of npt mRNA and amounts of active NPT enzyme are decreased. In addition, our data indicate that, at least in stable transformants, a large excess of ribozyme over target is not a prerequisite for achieving a significant reduction in target gene expression.
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    Molecular genetics and genomics 228 (1991), S. 361-371 
    ISSN: 1617-4623
    Keywords: Plant ; Hormone ; Genetics ; Hypocotyl ; Development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have isolated nine independent auxin-resistant mutants of Nicotiana plumbaginifolia by culturing M2 seedlings in the presence of indole-3-acetic acid ethyl ester or 1-naphthaleneacetic acid at concentrations which significantly inhibit hypocotyl elongation of the wild type. The mutations were induced by treating seed with ethyl methanesulphonate and were found in the course of screening 10 000 individual M2 families. Auxin resistance was in all cases the result of a mutation at a single, nuclear locus. The dominance relationships of two of the mutants could be defined as recessive or dominant; all other mutants showed partial dominance. In contrast to previously described mutants of Arabidopsis and N. plumbaginifolia, all of the present mutants were specifically resistant to auxin; the mutants were cross-resistant to several auxins, but showed no increased resistance to cytokinin, abscisic acid, ethylene or 1-amino-cyclopropane-1-carboxylic acid. The importance of the choice of the selection criterion for the isolation of specific resistance traits is discussed.
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  • 65
    ISSN: 1573-5133
    Keywords: Demography ; Genetics ; Geographic variation ; Stochasticity ; Fluctuating environments ; Allele frequencies ; River ecology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis The purpose of this study was to determine the effects of unpredictable environmental fluctuations on the demographic and genetic structure of Fundulus zebrinus populations. Collections of F. zebrinus were taken from three rivers in the Arkansas River basin: the Arkansas, Chikaskia, and Ninnescah. Fish were sampled from three sites on each river on nine collection dates throughout 1984 and 1985. Totals of 2100 fish and 6000 fish were included in electrophoretic and demographic analyses, respectively. The results of the study indicate that within a limited geographic region (i.e. within rivers) spatial differences and temporal changes in both demographic and genetic population characteristics occur frequently and are primarily stochastic. However, on a larger spatial scale (i.e. across rivers), general trends emerge for demographic and especially for genetic population characteristics. These results illustrate the importance of sampling scale for conclusions of life-history evolution in fluctuating environments. In addition, it was found that regulation of Fundulus zebrinus populations includes an important density-independent component. Stochastic demographic differences across space and changes through time and spatially and temporally heterogeneous allele frequencies, are both indicative of density-independent regulation. Variation in population parameters, both demographic and genetic, was observed between populations sampled from each river. These population differences were attributed to differences between the rivers themselves.
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    Environmental biology of fishes 6 (1981), S. 357-360 
    ISSN: 1573-5133
    Keywords: Behaviour ; Esterase ; Evolution ; Genetics ; Isozymes ; Stock structure ; Schools ; Starch gel
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Heterogeneous gene frequencies of Est-1 across groups ofNotropis cornutus provide evidence of behaviourally imposed restrictions on stock structuring. Positive fixation indices (F1S = 0.056 and F1T = 0.085) were reflected by a deficiency of heterozygotes for pooled groups. The degree of subdivision ofN. cornutus stocks cannot be evaluated with the present evidence. but it is likely that their schooling behaviour is associated with significant genotypic structuring of the species.
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    Environmental biology of fishes 8 (1983), S. 235-247 
    ISSN: 1573-5133
    Keywords: Amelanism ; Aggression ; Assessing mates ; Assortative mating ; Cheaters ; Chemical communication ; Coloration ; Context model ; Dominance ; Dummies ; Genetics ; Inhibition model ; Metamorphosis ; Nicaragua ; Parental care ; Polymorphism ; Sexual imprinting ; Visual communication
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis The midas cichlid,Cichlasoma citrinellum, occurs in the lakes of Nicaragua. In semi-turbid to turbid lakes about 8% of the adults are amelanic, having lost their melanophores at various ages, and are thus yellow through red and sometimes white. The commonest hues are yellow through orange, called gold. Gold morphs ought to be selected against because they are probably conspicuous to predators and they cannot communicate by changing markings. To maintain the polymorphism, gold coloration must have offsetting advantages. Gold morphs dominate normal ones of equal size, and that improves their access to limiting resources. Gold morphs, however, do not seem to be intrinsically more aggressive but rather attain dominance through the effect of their color on their opponents. This gold effect is affected by experience; it is enhanced by sharing the color of the dominant fish in a group, and by being rare. The midas cichlid mates assortatively but imperfectly. Choice of mate is influenced by color of self and of parents and can be constrained by size-color relationship.
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    Journal of chemical ecology 16 (1990), S. 2935-2946 
    ISSN: 1573-1561
    Keywords: Genetics ; sex pheromone ; Lepidoptera ; Noctuidae ; Trichoplusia ni ; cabbage looper moth ; reproductive isolation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The genetic basis of interpopulational differences in the pheromone blend emitted by the cabbage looper moth,Trichoplusia ni (Hübner), was examined by crossing individuals from a field-derived population (P1) with individuals from a long-maintained laboratory colony (P2). These colonies differed in the emission rate and relative proportions of four of the five known minor pheromone components, but not in the emission rate of the major component, (Z)-7-dodecenyl acetate (Z7-12∶Ac). These differences in pheromone blend were quantitatively small but biologically significant, because in the field, males responded preferentially to traps baited with a pheromone blend that is similar to that emitted by P1 females relative to a blend similar to that emitted by P2 females. In initial crosses, variation in the quantity and quality of pheromone blends among families of P1, P2, and F1 hybrid females was examined. In F1 females the relative proportions (quantity relative to the major component) of (Z)-5-dodecenyl acetate (Z5-12∶Ac) and (Z)-7-tetradecenyl acetate (Z7-14∶Ac) were intermediate to parental lines. In a second more extensive set of crosses, analyses included P1, P2, F1, F2, and selected backcrosses. The relative proportion of Z5-12∶Ac, Z7-14∶Ac, and Z9-14∶Ac emitted by F1 females were intermediate to parental lines. The frequency distributions of relative proportions of these components emitted by females were not consistent with those expected under a single autosomal or sex-linked gene hypothesis, suggesting that more than one gene is involved in the quantitative differences in the pheromone blend.
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  • 69
    ISSN: 1573-5060
    Keywords: Brassica oleracea ; Cauliflower ; Stalk rot ; Screening ; Genetics ; Resistance ; Sclerotinia sclerotiorum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The inheritance of resistance in cauliflower to stalk rot (Sclerotinia sclerotiorum (Lib.) de Bary) was investigated in population from six generations of six crosses. Disease incidence was recorded on 4 parents, 6 Fs 1, 6 Fs 2 and 12 back-crosses in a screenhouse under artificially created epiphytotic conditions. Resistance to stalk rot in this set of parents was found to be polygenic and under the control of recessive genes and due primarily to additive gene action. A breeding strategy emphasizing recurrent selection should lead to improvement in resistance.
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    Primates 34 (1993), S. 333-346 
    ISSN: 0032-8332
    Keywords: Genetics ; Pedigrees ; Molecular evolution ; Pan ; Hylobates ; Macaca ; DNA sequences ; Microsatellite loci
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Using DNA amplified from shed or plucked hair follicles it is now possible to genotype individual primates at many nuclear and mitochondrial gene loci. Sequence specific primers and the polymerase chain reaction permit the rapid production of sufficient DNA from a single hair for numerous analyses. The direct sequencing of relatively conservative mtDNA sequences like cytochromeb is proving useful in establishing species and subspecies-level relationships. More variable sequences (e.g. the mtDNA control region or D-loop) are useful at the population and social community levels. Paternity exclusion, pedigree relationships, and community structure can be determined using simple sequence length polymorphisms (SSLPs) of multiple hypervariable nuclear microsatellite or simple sequence repeat (SSR) loci. Studies involving captive and free-ranging chimpanzees, gibbons, and macaques illustrate the resolving power of these new non-invasive molecular genetic genotyping techniques.
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    Molecular Reproduction and Development 27 (1990), S. 168-172 
    ISSN: 1040-452X
    Keywords: Motility ; Genetics ; Sex chromosome ratio ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: In this study, we address the relationship between motility and genetic content of mouse sperm. The chromosome complements of highly motile mouse sperm, selected using the swim-up technique, were analyzed after in vitro fertilization, at the first cleavage state. They were compared to those of unselected sperm. Identification of male and female chromosome sets was possible because of their differential condensation at the first mitotic division. In vitro fertilization, swim-up separation, chromosome preparation, and staining were carried out using standard techniques. The results indicate that highly motile mouse sperm did not differ in types and frequencies of chromosomal abnormalities from those not selected for motility. Moreover, separation of motile sperm does not deviate the sex ratio from the theoretical 1:1.
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    Developmental Genetics 1 (1979), S. 1-1 
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
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    Developmental Genetics 1 (1979), S. 47-60 
    ISSN: 0192-253X
    Keywords: developmental mutants of Physarum ; apogamic mutants ; the amoebal-plasmodial transition ; myxomycete genetics ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: In the heterothallic myxomycete Physarum polycephalum, uninucleate amoebae normally differentiate into syncytial plasmodia following heterotypic mating. In order to study the genetic control of this developmental process, mutations affecting the amoebal-plasmodial transition have been sought. Numerous mutants characterized by self-fertility have been isolated. The use of alkylating mutagens increases the mutant frequency over the spontaneous level but does not alter the mutant spectrum. Three spontaneous and 14 induced mutants have been analyzed genetically. In each, the mutation appears to be linked to the mating type locus. In three randomly selected mutants, the nuclear DNA content is the same in amoebae and plasmodia, indicating that amoebal syngamy does not precede plasmodium development in these strains. These results indicate that a highly specific type of mutational event, occurring close to or within the mating type locus, can abolish the requirement for syngamy normally associated with plasmodial differentiation. These mutations help define a genomic region regulating the switch from amoebal to plasmodial growth.
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    Developmental Genetics 1 (1979), S. 77-95 
    ISSN: 0192-253X
    Keywords: Drosophila melanogaster ; pupae ; heat shock ; protein synthesis ; phenocopies ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Pupae of Drosophila melanogaster were heat-shocked under conditions required to induce phenocopies in more than 90% of the flies that subsequently emerge. The effects of these treatments on protein synthesis in two tissues (thoracic epithelium and brain) were followed for several hours after the heat treatments. Results from pulse-labeling and protein separations on sodium dodecylsulfate (SDS) acrylamide gels showed a virtually complete cessation of protein synthesis immediately after the shock, followed by a noncoordinate resumption of the starting pattern. Similar experiments following double heat shocks demonstrated a more rapid resumption of synthesis of heat shock proteins after two successive heat treatments than after a single one.
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    Developmental Genetics 1 (1979), S. 61-68 
    ISSN: 0192-253X
    Keywords: pink-eyed dilution locus ; spermatozoa ; sialic acid residues ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Abnormal spermiogenesis in sterile pink-eyed dilution mutants results in spermatozoa with bizarre sperm heads. The spermatozoa of normal mice bind colloidal iron hydroxide (CIH) along the length of the tail, yet the spermatozoa of pink-eyed sterile mice show a great reduction in ability to bind CIH. This implies a loss of negative surface charges. The group(s) responsible for the charges are sensitive to methylation but resistant to neuraminidase treatment, even after deacetylation with alkaline treatment. The membrane components containing the negatively charged groups may be neuraminidase-resistant forms of gangliosides.
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    Developmental Genetics 1 (1979), S. 21-46 
    ISSN: 0192-253X
    Keywords: Paramecium tetraurelia ; trichocysts ; nuclear differentiation ; cellular differentiation ; cytoplasmic inheritance ; developmental genetics ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Paramecium tetraurelia, stock d113, although completely homozygous, produces two kinds of genomically identical clones: N (nondischarge) clones incapable of trichocyst exocytosis (discharge) from intact cells in response to picric acid; and D (discharge) clones that do respond. These alternatives are irreversibly determined (at 27°C) during a determination sensitive period the first day after fertilization (autogamy, conjugation, or cytogamy): D parents are always determined to produce D progeny; N parents produce mostly N progeny if kept in exhausted medium, but mostly D progeny if kept in bacterized nutrient medium, throughout the sensitive period. If connecting bridges between mates persist long after the time for pair separation, the N member of N×D conjugant and cytogamous pairs produces D progeny even if exposed to exhausted medium throughout the sensitive period, thus indicating the presence in D mates of a D-determining cytoplasmic factor, δ, which overrides effects of external conditions. N and D determinations are brought about on newly developing somatic nuclei (macronuclear anlagen). After macronuclear development has been completed, determination is irreversible in it and its descendant macronuclei. M (mixed) clones produce N, D, and partial D cells; within these clones, diverse subclones can be selected. Crosses of d113 (N)×standard wild stock 51 (D) yield no segregation in F2, indicating no genomic difference between d113 (N) and wild type (D), δ may be a genic product regulating its own production. This results in “cytoplasmic inheritance” of D vs N in crosses of D×N followed by exhausted medium during the sensitive period. As with the only other well-analyzed comparable example, mating types, neither a genetic nor an epigenetic interpretation has yet been excluded for this system of developmental differentiation.
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    Developmental Genetics 1 (1979), S. 109-121 
    ISSN: 0192-253X
    Keywords: Dictyostelium discoideum ; alkaline phosphatase mutant ; linkage analysis ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Alkaline phosphatase is one of several enzymes that accumulate in a temporally regulated sequence during the development of Dictyostelium discoideum. These enzymes can be used to monitor specific gene expression; moreover, isolation and analysis of mutations in the structural gene(s) can serve to indicate some of the essential steps in programmed synthesis and morphogenesis. A mutation (alpA) which affects the activity and substrate affinity of alkaline phosphatase was isolated in D discoideum using a procedure for screening large numbers of clones. Alkaline phosphatase activity at all stages of vegetative growth and development was altered by the mutation. Several physical properties of the enzyme from growing cells and developed cells were compared and found to be indistinguishable. It is likely that a single enzyme is responsible for the majority of alkaline phosphatase activity in growth and development. The mutation is coexpressed in diploids heterozygous for alpA and maps to linkage group III. One of the haploid segregants isolated from these diploids carries convenient markers on each of the six defined linkage groups and can be used for linkage analysis of other genetic loci.
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    Developmental Genetics 1 (1979), S. 167-179 
    ISSN: 0192-253X
    Keywords: agouti locus ; hair pigment patterns ; melanocyte metabolism ; tissue microenvironment ; eumelanin ; phaeomelanin ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: This study was conducted to assess microenvironmental variability within integumental tissue of genetically identical mice with respect to a specific cellular response: cyclic synthesis of yellow and black pigment by hair bulb melanocytes. Crosses were performed within and between inbred strains of mice that were isogenic with the exception of a single gene substitution at the agouti locus. Agouti locus genes included the Avy, Aw, A, atd, at, ax, am, and a alleles. The pigment patterns of dorsal, flank, and ventral hairs of the first and third hair generations and of hairs growing in special integumentary areas such as the pinna, tail, and hind foot were studied. It was found that the amount of yellow pigment synthesized by hair bulb melanocytes within genetically identical mice is both agedependent and conditioned by the integumentary environment. Furthermore, the special integumentary regions produce hairs with a variety of pigment patterns in which the distribution and relative amounts of black and yellow pigments do not necessarily conform to dominance relationships expected among agouti locus alleles as judged by their effects on the pigmentation of the dorsal pelage. We conclude that within genetically uniform integumental tissues, microenvironmental differences occur and are reflected as alterations in the metabolic pattern of differentiated cells.
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    Developmental Genetics 1 (1979) 
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
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    Developmental Genetics 1 (1979), S. 195-204 
    ISSN: 0192-253X
    Keywords: apterous mutant ; Drosophila melanogaster ; juvenile hormone ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The apterous (ap) mutant in Drosophila melanogaster exhibits phenotypes of wing deficiency, precocious adult death, and nonvitellogenic oocyte development. The latter phenotype previously has been shown to result from juvenile hormone (JH) deficiency in the adult stage. To explore the relationship between the hormone deficiency and the other phenotypes, the expression of each phenotype was measured in five alleles of ap (including a new, chemically-induced allele, ap77f) as wing length, survival five days after eclosion, and initiation and progress of vitellogenic oocyte development. No correlation could be found between severity of wing phenotype and that of precocious adult death or nonvitellogenesis. However, the latter phenotypes were correlated in both ap homozygotes and allelic heterozygotes, since adults that survive have wild-type vitellogenesis, and those fated for precocious death fail to develop vitellogenic oocytes. These results indicate that no relationship exists between wing and JH deficiencies, but that precocious adult death is related to hormone deficiency  -  probably through pleiotropy, rather than through causality.
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    Developmental Genetics 1 (1979), S. 205-218 
    ISSN: 0192-253X
    Keywords: Tetrahymena thermophila ; genomic exclusion ; micronucleus ; macronucieus ; nucleocytoplasmic interactions ; developmental cytogenetics ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Genomic exclusion is an aberrant form of conjugation of Tetrahymena thermophila in which the genome of a defective conjugant is excluded from the genotype of the exconjugant progeny. This paper is concerned with the cytogenetic and nucleocytoplasmic events of genomic exclusion in senescent clones A*III and C*. In crosses between A*III or C* and strain B, functional, haploid gametic nuclei are formed only in the strain B cell. In some instances one of the gametic nuclei divides prior to transfer of the migratory gametic nucleus, and both products then undergo DNA synthesis. Two alternative cytogenetic pathways are followed after transfer of the migratory nucleus. In the first, the conjugants separate without further micronuclear divisions. This pathway was most common in A*III genomic exclusion. In exconjugants the former gametic nuclei undergo both DNA synthesis and (presumably) intranuclear separation of centromeres to restore micronuclear diploidy. The old macronucleus of each exconjugant is retained without autolysis. This class of exconjugant survives and contributes genes to future sexual progeny. In the second cytogenetic pathway the gametic nuclei divide and macronuclear anlagen are formed, as in normal conjugation. This pathway was more common in C* genomic exclusion. The initial DNA content of the anlagen ranges from haploid to diploid. Following two to three rounds of DNA synthesis, further macronuclear development ceases and the anlagen appear to undergo autolysis. The old macronucleus condenses and also undergoes autolysis, as in normal conjugation. Except for rare C* exconjugants, in which macronuclear development is completed, anlagen-bearing genomic exclusion exconjugants die. Death may be caused by aneuploidy, errors in the timing or receptivity to signals for autolysis, or the inability of anlagen-bearing exconjugants to feed. Anlagenbearing conjugants are frequently abnormal with respect to the number of anlagen and micronuclei. Most of the anomalies can be explained by postulating errors in the timing of both developmental signals and nuclear divisions. Rare conjugants in which gametic nuclei divide but do not give rise to macronuclear anlagen are also observed. In these instances, the old macronuclei condense and undergo autolysis. Destruction of the old macronucleus therefore is independent of the presence of macronuclear anlagen and requires cell pairing in order to be initiated.
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    Developmental Genetics 1 (1979), S. 241-246 
    ISSN: 0192-253X
    Keywords: β-glucosidase mutants ; dictyostelium ; developmental regulation ; linkage group VI ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Seven mutations affecting β-glucosidase activity in Dictyostelium discoideum were found to be non-complementing, recessive to the wild-type allele, and to occur in the gene locus, gluA. This gene, which is likely to be the structural gene for β-glucosidase, since a mutation in it gives rise to thermolabile activity and other mutations in it result in no measurable activity, was mapped to linkage group VI. The expression of the β-glucosidase gene is regulated such that the enzyme is synthesized during the growth phase and during culmination, but not during the first 18 hours following the initiation of development. If expression of the structural gene required the function of a positive regulatory protein coded for by a gene as mutable as the gluA gene, there was greater than 99% chance one of the mutations of this series would have affected the regulatory locus. The absence of a second complementing locus for β-glucosidase suggests that this enzyme is regulated by other means.
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    Developmental Genetics 1 (1979), S. 257-269 
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: A protein which has been shown to inhibit catalase in vitro appears to vary inversely with catalase activity in the maize scutellum during early sporophytic development when assayed using a catalase inhibition assay. This result suggested that the inhibitor protein may play a direct role in regulating catalase activity during this time period.Four experimental approaches were used to evaluate this putative regulatory role, including immunological quantitation of individual catalase isozymes during germination using rocket immunoelectrophoresis, perturbation of normal catalase expression with hydrogen peroxide or allylisopropylacetamide (AIA), examination of a mutant line with an altered catalase developmental program, and direct radioimmunoassay of the inhibitor protein during germination. The results of these experiments indicate that the quantitative changes in catalase activity during development are not mainly due to changes in the expression of the catalase inhibitor. Other possible roles of this protein in catalase regulation are discussed.
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    Developmental Genetics 2 (1981) 
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
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    Developmental Genetics 1 (1979), S. 355-362 
    ISSN: 0192-253X
    Keywords: Dictyostelium discoideum ; spore maturation ; spore specific mutations ; cell patterning ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Three mutations affecting spore maturation in the asexual fruiting body of Dictyostelium discoideum are assigned to a new locus, sprJ, on linkage group IV. Strains carrying mutations at the sprJ locus do not form mature spores, yet the cell patterning (spore, stalk and disc cell ratios) is apparently normal. These mutations will be useful to delineate branch points between the cell patterning and spore maturation pathways. There are some unusual features of the sprJ-containing mutants. In particular each of the parent strains of the three mutants has incomplete spore maturation as determined by colony-forming ability after heat shocking at 45°C. A mutation allowing growth in the presence of benlate (600 μg/ml), benA351, is mapped to linkage group I.
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    ISSN: 0192-253X
    Keywords: nuclear differentiation ; cytoplasmic inheritance ; Paramecium tetraurelia ; mating type ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: In P. tetraurelia each cell is determined to express only one of the two complementary mating types, O and E. This determination is under cytoplasmic control and seems to be achieved only by the commitment or noncommitment to the expression of mating type E. All the previously known mutations affecting the differentiation of mating type prevent the expression of the E mating type (O-restricted mutations) without affecting the determination process. An E-restricted mutation was obtained: mtFE. Its phenotypic properties indicate that the mutation affects the determination process itself. When an O cell becomes mtFE/mtFE it acquires the E mating type and an E-determining cytoplasm. We propose that this constitutive determination for the E mating type is due to the inefficiency of a factor which is normally active in an O cell. This factor would act like a repressor and stabilize the E functions under an inactive state.
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    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 2 (1981), S. 279-290 
    ISSN: 0192-253X
    Keywords: temperature-sensitive mutant ; cytokinin ; hormonal metabolism ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Developmental controls of morphological mutants of Phaseolus vulgaris L. conditioned by two independent loci, DL1 and DL2, were examined through grafting experiments and hydroponic studies. Phenotypes of mutant classes were duplicated by unions of scions and stocks derived from different genotypes. Results indicate that DL1 and DL2 regulate a root and shoot factor respectively, contributing to the mutant types. The allelic dosages of DL1 in the root and DL2 in the shoot rather than the genotype of the whole plant per se determine the severity of the mutant expression. Plants heterozygous for both loci with a temperature-sensitive expression of the mutant phenotype were used to determine physiological components involved. The primary abnormal developmental event associated with the appearance of mutant phenotypes, the restricted root growth at high temperature, could be overcome by the addition of cytokinin in hydroponic solution. These observations suggest that DL1 and DL2 may be related to the regulation of hormonal function or metabolism.
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  • 88
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    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 2 (1981) 
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
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  • 89
    ISSN: 0192-253X
    Keywords: suspensive and adhesive teratoma cells ; teratoma embryoid bodies ; cell differentiation ; endogenous prostanoid biosynthesis ; long-chain fatty acyl CoA derivatives ; mass fragmentography ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Attachment of the cell surface to a substratum may play a critical role in initiating some cellular developmental commitments and in sustaining differentiation of cells that have already been specialized. Embryoid bodies of teratoma OTT6050 were divided, on day 10 of initial culture, into myogenic adhesive cells which were already (at day 6) characterized by endogenous prostaglandin (PG)I2 formation and little-specialized suspensive cells which formed only thromboxane (TX)B2 in the same culture system. Since at day 10 both cell types reached a stationary phase in which the nature of each cell was mature enough for the analyses with mass fragmentographic technique and gas chromatography- mass spectrometry (GCMS), the total levels of predominant long-chain fatty acyl CoA (acyl CoA) derivatives could be measured comparatively as methyl esters after methanolysis. It was found as a result of major differentiation that adhesive cells had a rather low ratio of arachidonyl CoA to stearyl CoA, although adhesive cells accumulated a larger total amount of acyl CoA derivatives than that accumulated in suspensive cells.
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  • 90
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    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 2 (1981), S. 99-111 
    ISSN: 0192-253X
    Keywords: CIPC as a mitotic inhibitor of Dictyostelium ; inhibition of Dictyostelium development by CIPC ; CIPC-resistant mutants ; Dictyostelium ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The anti-mitotic herbicide isopropyl N-(3-chlorophenyl) carbamate (CIPC) prevents the growth of amoebae of Dictyostelium discoideum without killing the cells for a period of time equivalent to one generation. During in-hibition, amoebae accumulate in prophase and metaphase of mitosis. After removal of CIPC, they continue through mitosis and then divide.The addition of CIPC to amoebae under starvation conditions prevents aggregation and concomitant cell elongation. The cells, however, do not lose their ability to adhere to a surface, and they remain viable. When CIPC is added to amoebae which have formed streams, it leads to the disintegration of streams into small clusters of cells and to a loss of cell elongation.Post-aggregation stages of development can be inhibited by CIPC at the mound, slug, or Mexican hat stages. Slugs break apart into distinct aggregates.Mutants resistant to CIPC can be obtained easily. Among these mutants, many become temperature sensititive for growth (27°C) or development (27°C or 15.5°C). Others show various abnormalities at the normal temperature (22°C). Most mutants are cross resistant to the microtubule inhibitors nocodazole and thiabendazole, and some are also resistant to CIPC during development.
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  • 91
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    Developmental Genetics 2 (1981), S. 147-158 
    ISSN: 0192-253X
    Keywords: triplo-lethal locus ; Tpl ; gene-dosage ; X chromosome ; Drosophila melanogaster ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Only a single locus (Tpl) is known in the Drosophila melanogaster genome that leads to early lethality when present as a heterozygous duplication (three doses) or deficiency (one dose). We report the recovery of third instar larvae (and of occasional adults) carrying a duplication for the triplo-lethal locus, Dp(Tpl). Karyotype analysis of the larvae showed that the individuals surviving were almost entirely 3X;2A metafemales. We examined the question of whether the entire X or a single X locus was a major factor permitting survival. X-Y translocations were used to produce females hyperploid for different portions of the X and carrying Dp(Tpl). Analysis of metaphase chromosomes by quinacrine fluorescence pattern indicates that the X chromosome region between 6D and 7DE must be present in an extra copy to enhance the survival of Tpl duplication-bearing females. Another type of experiment suggests that it is the region between 7C and 7DE which is essential.
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  • 92
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    Developmental Genetics 3 (1982), S. 1-6 
    ISSN: 0192-253X
    Keywords: glycerol-3-phosphate dehydrogenase ; isozymes ; mice ; genetics ; development ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Genetic variants that affect the heat stability and ionic charge of the adult isozyme of glycerol-3-phosphate dehydrogenase (EC 1.1.1.8) map to a gene, Gdc-1, located on chromosome 15. A second isozyme of glycerol-3-phosphate dehydrogenase, structurally homologous to the product of the Gdc-1 locus and expressed predominantly in undifferentiated tissues, has previously been identified. We have now discovered an electrophoretic variant of this embryonic isozyme. This expression is determined by a codominant allele of the gene, Gdc-2, that maps to the distal end of chromosome 9 as inferred from the observed gene order Mpi-1-d-Mod-1-Gdc-2.
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  • 93
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    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 3 (1982), S. 273-273 
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
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  • 94
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    Developmental Genetics 3 (1982), S. 299-308 
    ISSN: 0192-253X
    Keywords: survival ; selection ; heat-shock proteins ; Drosophila melanogaster ; temperature compensation ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Two stocks of Drosophila melanogaster, one sensitive (6.5% survival) and one resistant (76.24%) to heat shock (40°C/25 min) were derived through indirect selection [1]. Genetic analysis of heat-sensitive and heat-resistant lines we had selected revealed that the survival rate is chiefly determined by cytoplasmic inheritance but also depends to some extent on the nucleus [1]. The ability of the fly to survive thermal stress was found to have an excellent correlation with the kinetics of protein synthesis in ovaries or glands subjected to heat treatment. The incorporation rate of 35S-methionine into proteins was found to be higher for strains exhibiting higher survival (R1, R1S1) than for strains with a lesser ability (S1, S1 R1) to survive heat shock. Moreover, the intensity of labeling of the proteins synthesized and especially of the hsps (heat-shock proteins) after the heat shock is higher in the R1 and R1S1 stocks than in the S1 and S1R1 stocks. This convergence between survival and the cellular level of hsps (both manipulated by selection) bears on the physiological significance of these proteins which seems to participate in the control of the survival as an additive component.
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  • 95
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    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 3 (1982), S. 371-372 
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
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  • 96
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    Developmental Genetics 4 (1983), S. 21-29 
    ISSN: 0192-253X
    Keywords: agouti locus ; embryonic lethal ; ax ; lethal nonagouti ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The time and mode of action of the homozygous ax gene, lethal nonagouti, has been investigated on the inbred AX/Pa background. Heterozygotes were mated inter se to produce 25% homozygous embryos and heterozygotes were mated with homozygous, nonagouti mice to provide control litters. Comparisons of the frequency of mating success, the ratio of implantation sites to ovarian ovulation sites, and the average litter sizes between experimental and control matings all indicated that ax/ax embryos are not lost prior to implantation. Histological examination of pregnant uteri indicated that ax/ax embryos are first evident as abnormal blastocysts at 4.5 days post coitum (pc). These implant and develop to varying degrees, some differentiating trophoblast giant cells and a primitive endoderm layer. Growth is retarded and only small, disorganized clumps of tissue remain by 7.5 and 8.5 days pc. The time and mode of gene action of lethal nonagouti is thus different from its allele, lethal Yellow.
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  • 97
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    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 4 (1983), S. 61-68 
    ISSN: 0192-253X
    Keywords: cell adhesion ; macromolecular ; sponge factors ; Dictyostelium ; adhesion-blocking antiserum ; staggerer mutant ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Cellular adhesion is what keeps cells together in multicellular organisms. Cells adhere to each other, to extracellular matrices, and to the substratum. Biochemical analyses of these processes have suggested some of the types of surface molecules which may be involved, but definitive evidence must rely on effective reconstruction of functional membranes or genetic alteration of the pertinent genes. Together these approaches may give us a better understanding of how cells sort out and form tissues during development.
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  • 98
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    Developmental Genetics 3 (1982), S. 197-205 
    ISSN: 0192-253X
    Keywords: mouse fetal erythrocyte antigen ; erythropoiesis ; differentiation ; gene switching ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Bone marrow cells from normal adult mice were introduced by microinjection via the placenta into W/Wv genetically anemic fetuses of 11 days' gestation. After birth, erythrocytes were fractionated by fluorescence-activated cell sorting on the basis of antibody binding to a fetal-specific antigen (Ft). Lysates of Ft-positive, i.e., fetal, erythrocytes did not detectably contain hemoglobin of the donor type, as judged from electrophoresis of strain-specific hemoglobin variants. Thus, adult hematopoietic bone marrow cells did not resume fetal differentiation despite their post-transplant maturation in a fetal environment.
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  • 99
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    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 3 (1982), S. 255-272 
    ISSN: 0192-253X
    Keywords: salivary glands ; pupation stage ; protein synthesis and transport ; prepupal development ; developmentally regulated proteins ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Pulse-labeling experiments of salivary glands from the prepupal stages of development showed selectively high rates of synthesis of a set of low molecular weight proteins (6K-12K). These proteins are stably maintained in the salivary glands during prepupal development and are subsequently transported to the pupation fluid (found between the pupal case and the prepupal cuticle) when pupation occurs. These small polypeptides are very basic with the major components having isoelectric points of 8.6-8.7 and the minor components having isoelectric points of 9.1-9.5. This study shows the continuing function of the salivary glands - specifically, the synthesis and secretion of a set of proteins with a putative role in pupation.
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  • 100
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    Developmental Genetics 4 (1983), S. 333-339 
    ISSN: 0192-253X
    Keywords: Drosophila ; chromosome ; polyteny ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: A 315 kb walk in the genetically well characterized rosy region of the Drosophila chromosomes permits a molecular analysis of chromosome organization. Polytene chromosome bands in this region range from less than 7 kb to about 160 kb and the level of DNA replication is constant within bands and among bands and interbands. A good numerical and topographical correspondence is found between chromomeric units and genetic units.
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