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  • Genetics  (650)
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    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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  • 2
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    Springer
    Cellular and molecular life sciences 44 (1988), S. 491-495 
    ISSN: 1420-9071
    Keywords: Genetics ; stress ; emotionality ; locus ceruleus ; Maudsley strains
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The Maudsley Reactive and Non-Reactive strains have been developed as a model for the study of individual variations in stress-reactivity, and many differences in biobehavioral systems have been found between them. This review discusses limitations of the ‘emotionality’ construct in accounting for differences between the Maudsley strains and offers an alternative, theoretical approach. Amaral and Sinnamon have proposed that the locus ceruleus (LC) plays a stress-attenuating role in mediating behavioral, physiological and neuroendocrine response to prepotent, emergency-provoking stimuli and, building upon this formulation, it is proposed that the LC has been an important focus for gene action in the Maudsley model. It is suggested that the LC of the Non-Reactive strain is more strongly activated by stressful stimuli than the LC of Reactive rats, and is the basis of many of the behavioral and physiological differences between them. Behavioral and biochemical evidence consistent with this proposition is reviewed. Identification of the LC as a target for gene-action in the Maudsley model has an important advantage. It substitutes variations at a specific anatomic location in the brain for a loosely defined construct like emotionality, and the hypothesis is amenable to empirical tests by a variety of experimental approaches.
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  • 3
    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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  • 4
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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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  • 5
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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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  • 6
    ISSN: 1432-1939
    Keywords: Logging disturbance ; Land gastropods ; Ecology ; Genetics ; Population
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Ecological and genetic properties of two North American terrestrial gastropods (Mesomphix spp.) were characterized in paired control and previously logged watersheds in two North Carolina forests (Coweeta and the Great Smoky Mountains National Park) of the Southern Appalachian Biosphere Reserve Cluster. Shell growth was greater in the control sites, but density and mortality were largely independent of prior logging history and forest reserve. Based on starch gel electrophoresis data, both species showed their highest levels of genetic diversity in the Coweeta forest, the component of the reserve cluster which had the most extensive and variable history of logging disturbance. M. subplanus also exhibited higher levels of heterozygosity in logged than in control watersheds, and M. andrewsae showed over twice as many rare alleles in disturbed sites as in control sites. F-statistic analysis depicted both excess levels of homozygosity and moderate genetic differentiation among the populations, reflecting the effects of small population size and perhaps drift and inbreeding. Estimated gene flow was relatively low. These results correspond to the recent finding by Bryant et al. (1987) and others on the effects of bottlenecks, and to the contrasting history of habitat instability of the two major study forests.
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  • 7
    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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  • 8
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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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  • 9
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    Archives of microbiology 149 (1987), S. 36-42 
    ISSN: 1432-072X
    Keywords: Catabolite repression ; Genetics ; Malate dehydrogenase ; Molecular cloning ; Sequence ; CRP binding site ; Escherichia coli
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The malate dehydrogenase gene of Escherichia coli, which is susceptible to catabolite and anaerobic repression, has been cloned using plasmic pLC32-38 of Clarke and Carbon (1976). The nucleotide sequence was determined of a 2.47 kbp fragment, containing the mdh structural gene. All information necessary for expression of the mdh structural gene was mapped within a 1.3 kbp SphI-BstEII fragment. Compared with the untransformed wild type, transformations with pUC19 vector, containing this fragment, gave up to 40-fold more malate dehydrogenase activity in both E. coli wild type and mdh mutant recipients. Catabolite repression was not affected in the transformants. A possible CRP binding site in the promotor region of the mdh gene provides evidence for a co-regulation with fumA gene, the structural gene of fumarase, which is also subject to catabolite repression. The structures for transcription initiation and termination were similar to those previously described for E. coli. Amino acid sequence homologies between pro- and eucaryotic malate dehydrogenases are discussed.
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  • 10
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    Archives of microbiology 152 (1989), S. 335-341 
    ISSN: 1432-072X
    Keywords: Carboxydotrophic bacteria ; Plasmids ; CO dehydrogenase subunits ; N-terminal sequences ; Oligonucleotides ; Hybridization ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The 17 (S), 30 (M) and 87 kDa (L) subunits of CO dehydrogenases from the CO-oxidizing bacteria Pseudomonas carboxydoflava, Pseudomonas carboxydohydrogena and Pseudomonas carboxydovorans OM5 were isolated and purified. The N-terminal sequences of same subunits from different bacteria showed distinct homologies. Dot blot hybridization employing oligonucleotide probes derived from the sequences of the S-subunit of P. carboxydovorans OM5 and the M-subunit of P. carboxydohydrogena and DNA of the plasmid-containing CO-oxidizing bacteria Alcaligenes carboxydus, Azomonas B1, P. carboxydoflava, P. carboxydovorans OM2, OM4 and OM5 indicated that all genes encoding these subunits reside on plasmids. That in P. carboxydovorans OM5 CO dehydrogenase structural genes are located entirely on plasmid pHCG3 was evident from the absence of hybridization employing DNA from the cured mutant strain OM5-12. CO dehydrogenase structural genes could be identified on the chromosome of the plasmid-free bacteria Arthrobacter 11/x, Bacillus schlegelii, P. carboxydohydrogena and P. carboxydovorans OM3. There was no example of a plasmid-harboring carboxydotrophic bacterium that did not carry CO dehydrogenase structural genes on the plasmid. The N-terminal sequences of CO dehydrogenase structural genes were found to be conserved among carboxydotrophic bacteria of distinct taxonomic position, independent of the presence of plasmids. It is discussed whether this might be the consequence of horizontal gene transfer.
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  • 11
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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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  • 12
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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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  • 13
    ISSN: 1432-2242
    Keywords: Triticum aestivum L. ; Doubled-haploids ; Genetics ; Androgenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    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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  • 14
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    Theoretical and applied genetics 67 (1984), S. 97-111 
    ISSN: 1432-2242
    Keywords: Genetics ; Nitrogen ; Grain crops ; Selection ; Plant breeding
    Source: Springer Online Journal Archives 1860-2000
    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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  • 15
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    Theoretical and applied genetics 69 (1984), S. 15-21 
    ISSN: 1432-2242
    Keywords: Genetics ; Heat tolerance ; Thyroid function ; Chickens
    Source: Springer Online Journal Archives 1860-2000
    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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  • 16
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    Theoretical and applied genetics 71 (1985), S. 39-43 
    ISSN: 1432-2242
    Keywords: Peas ; Genetics ; Foliage ; Heterozygosity ; Heterosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Eight near-isogenic lines of pea representing all the homozygous combinations of three genes af, st and tl, which modify leaf shape and size, were crossed in all possible ways excepting reciprocals. An analysis of the resulting 36 families has shown that homozygous mutant alleles at the tl locus acting with homozygous mutant alleles at the af and st loci increase both seed weight and plant haulm weight. The mutant alleles at the af and st loci seem, when homozygous, to have little effect by themselves upon seed weight but they do increase or decrease haulm weight, respectively. There is clear evidence of heterotic effects resulting from heterozygosity at each one of the three loci which modify seed weight, haulm weight and basal branching. The implications of such heterotic effects in pea breeding programmes are discussed.
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  • 17
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    Theoretical and applied genetics 71 (1986), S. 607-612 
    ISSN: 1432-2242
    Keywords: Taxonomy ; Germplasm identification ; Varietal identity ; Environmental interaction ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Alcohol soluble seed storage proteins (zeins and alcohol soluble glutelins) of maize (Zea mays L.) were separated by reversed-phase high-performance liquid chromatography (RP-HPLC). The objectives were to assess the reproducibility of chromatographic profiles using seed of inbred lines that had been produced in different locations and years. Reproducible differences between sources were seen but these were restricted to proteins that contributed 2% or less to an inbred profile. The majority of variation (93% for peak percent area; 99.8% for elution time) was between inbreds. RP-HPLC can therefore provide distinctive phenotypic profiles that are largely characteristic of genotype. Such qualitative and quantitative data will be valuable for studies of taxonomy, evolution, genetics, and germplasm identification.
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  • 18
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    Theoretical and applied genetics 73 (1986), S. 278-285 
    ISSN: 1432-2242
    Keywords: Genetics ; Gliadins ; Gene clusters ; Recombination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Analysis of F2 grains from two different crosses has revealed a complex organization of the family of gliadin-coding genes located on chromosomes of the first homoeological group in hexaploid wheat. Chromosome 1A of variety ‘Bezenchukskaya 98’ was found to carry at least five gliadin-coding genes of which three genes form a cluster controlling the synthesis of the GLD1A1 block. Two additional genes are located on the both sides of this cluster and recombine with it at frequencies of 5±1.3% and 13±2.9%. Gliadinencoding genes recombining with the main clusters were also found on chromosomes 1B and 1A in the ‘Bezenchukskaya 98’ and ‘Saratovskaya 210’ varieties, respectively. In ‘Chinese Spring’, widely used in genetic studies, we discovered a recombination between genes located on chromosome 1A and controlling the synthesis of ω- and γ-gliadins. Varieties and biotypes of one variety may differ by the presence or absence of such “selfish” (not included in clusters) gliadin components. The similarity of organization of prolamine-coding genes on chromosomes in different cereals is considered.
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  • 19
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    Theoretical and applied genetics 73 (1987), S. 440-444 
    ISSN: 1432-2242
    Keywords: Secale cereale L. ; Genetics ; α-Amylase ; Isozymes ; Modifiers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Fifteen inbred lines of rye, F1 and F2 progenies from crosses between lines were studied using polyacrylamide gel electrophoresis. Conventional genetic analysis of α-amylase zymograms showed that the 19 bands detected in the endosperm of germinating caryopses were controlled by three linked structural loci and one independent modifying locus, which influenced the electrophoretic mobility of isozymes. Two codominant alleles were found at the α-Amy1, α-Amy2 structural loci and the M-α-Amy modifying locus while the α-Amy3 locus had three alleles. Double-banded expression of the α-amylase alleles was probably due to the simultaneous presence of modified and unmodified forms of isozymes on the zymogram.
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  • 20
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    Theoretical and applied genetics 78 (1989), S. 97-104 
    ISSN: 1432-2242
    Keywords: Beta vulgaris ; Sugar beet ; Isozymes ; Genetics ; Linkage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Five isozyme systems were genetically investigated. The different separation techniques, the developmental expression and the use as marker system in sugar beet genetics and breeding is discussed. Isocitrate dehydrogenase was controlled by two genes. The gene products form inter- as well as intralocus dimers, even with the gene products of the Icd gene in B. procumbens and B. patellaris. Adenylate kinase was controlled by one gene. Three different allelic forms were detected, which were active as monomeric proteins. Glucose phosphate isomerase showed two zones of activity. One zone was polymorphic. Three allelic variants, active as dimers, were found. Phosphoglucomutase also showed two major zones of activity. One zone was polymorphic and coded for monomeric enzymes. Two allelic forms were found in the accessions studied. The cathodal peroxidase system was controlled by two independent genes, of which only one was polymorphic. The gene products are active as monomers. Linkage was found between red hypocotyl color (R) and Icd 2. Pgm 1, Gpi 2, Ak 1 and the Icd 2-R linkage group segregated independently.
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  • 21
    ISSN: 1432-2242
    Keywords: Solanum tuberosum ; Genetics ; Breeding ; Plant appearance ; Economy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In 1985, 1986 and 1987, 600 clones were visually assessed at harvest on plant appearance. The clones were harvested 80 days after planting in the first year, in the following years after approximately 80 days as well as after 145 days. The correlation coefficients between years and between harvest times were low to medium. Simulating different selection intensities using the performance of these 600 clones in two successive years, the relation between selection pressure in the first year and the retained proportion of well performing clones in the second year was described. Including the costs of testing, the most economic selection procedure was calculated. This procedure consisted in testing 1,579 first-year clones and 499 second-year clones for every 100 third-year clones required. The optimal period of the main evaluation in the second clonal year is at ware potato harvest time. This selection procedure also provides good selection possibilities for underwater weight and foliage maturity.
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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
    Source: Springer Online Journal Archives 1860-2000
    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 71 (1985), S. 461-466 
    ISSN: 1432-2242
    Keywords: Hordeum vulgare ; β-glucan ; Doubled haploids ; Genetics ; Correlated characters
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Random inbred lines produced by doubled haploidy (DH) and single seed descent (SSD) have been used to investigate the genetics of β-glucan (gum) content in barley (Hordeum vulgare). Genetical analyses indicated that gum content is controlled by a simple additive genetic system. Significant negative genetic correlations were observed between β-glucan content, thousand grain weight and height in the DH samples. These correlations were much reduced in the SSD samples and would suggest linkage of the genes controlling these characters. The presence of repulsion linkages could be exploited in a barley breeding programme by producing F1 derived DH to generate recombinants with high thousand grain weight and low β-glucan content. Genetical parameters estimated from DH and F3 samples have successfully been used to predict the number of inbred lines transgressing the parental range for β-glucan content and bivariate combinations involving β-glucan.
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  • 24
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    Theoretical and applied genetics 75 (1988), S. 889-901 
    ISSN: 1432-2242
    Keywords: Soybean ; Restriction fragment length polymorphism ; Genetics ; Allele ; Variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Restriction Fragment Length Polymorphisms (RFLP) have been identified between widely distant cultivars (‘Minsoy’ and ‘Noir 1 ’) of soybean Glycine max (L.) Merrill. Using as probes randomly chosen clones of DNA, one in five probes revealed a polymorphism. More than half of these polymorphisms appear to result from rearrangements of the genomic DNA. Twenty seven markers were analyzed for linkage in F2 plants. Eleven of these markers were contained in four linkage groups. Five cultivars were compared in a search for new alleles. When RFLP markers corresponding to low copy DNA were used to analyze three other cultivars — ‘Sooty’, ‘Forrest’ and ‘Mandarin (Ottawa)’ — few new alleles were found. Using these probes, five different markers could be used to differentiate the five cultivars. Complex probes, which correspond to repeated DNA, revealed different polymorphisms in different cultivars and a single such probe could be used to distinguish the five cultivars from each other.
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  • 25
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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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  • 26
    ISSN: 1432-2242
    Keywords: Genetics ; Loci ; Powdery mildew ; Prolamin ; Recombination
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    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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  • 27
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    Theoretical and applied genetics 60 (1981), S. 229-236 
    ISSN: 1432-2242
    Keywords: Glutenin ; Triticum ; Genetics ; SDS ; Polyacrylamide-gel-electrophoresis
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    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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  • 28
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    Theoretical and applied genetics 60 (1981), S. 265-268 
    ISSN: 1432-2242
    Keywords: Agrocybe ; Genetics ; Fruiting ; Biomass
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    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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  • 29
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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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    Theoretical and applied genetics 62 (1982), S. 233-239 
    ISSN: 1432-2242
    Keywords: Hordeum vulgare ; Haploids ; Androgenetic responsiveness ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    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 74 (1987), S. 177-187 
    ISSN: 1432-2242
    Keywords: Barley ; Grain development ; Mutants ; Ultrastructure ; Genetics
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    Topics: Biology
    Notes: Summary Eleven Na-azide induced barley shrunken endosperm mutants expressing xenia (sex) were characterized genetically and histologically. All mutants have reduced kernel size with kernel weights ranging from 11 to 57% of the wild type. With one exception, the mutant phenotypes are ascribable to single recessive mutant alleles, giving rise to a ratio of 3∶1 of normal and shrunken kernels on heterozygous plants. One mutant (B10), also monofactorially inherited, shows a gene dosage dependent pattern of expression in the endosperm. Among the 8 mutants tested for allelism, no allelic mutant genes were discovered. By means of translocation mapping, the mutant gene of B10 was localized to the short arm of chromosome 7, and that of B9 to the short arm of chromosome 1. Based on microscopy studies, the mutant kernel phenotypes fall into three classes, viz. mutants with both endosperm and embryo affected and with a non-viable embryo, mutants with both endosperm and embryo affected and with a viable embryo giving rise to plants with a clearly mutant phenotype, and finally mutants with only the endosperm affected and with a normal embryo giving rise to plants with normal phenotype. The mutant collection covers mutations in genes participating in all of the developmental phases of the endosperm, i.e. the passage from syncytial to the cellular endosperm, total lack of aleurone cell formation and disturbance in the pattern of aleurone cell formation. In the starchy endosperm, varying degrees of cell differentiation occur, ranging from slight deviations from wild type to complete loss of starchy endosperm traits. In the embryo, blocks in the major developmental phases are represented in the mutant collection, including arrest at the proembryo stage, continued cell divisions but no differentiation, and embryos deviating only slightly from the wild type.
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    Theoretical and applied genetics 74 (1987), S. 439-444 
    ISSN: 1432-2242
    Keywords: Wheat ; Callus ; Regeneration ; Tissue culture ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Calli were initiated from immature embryos of nine lines of hexaploid wheat (Triticum aestivum L. em. Thell). These were the euploid lines Chinese Spring and Cappelle-Desprez, a line of Chinese Spring ditelocentric for the long arm of 4B, four substitution lines of Chinese Spring in which chromosome 4B has been replaced by its homologues from different wheat varieties and substituted into Chinese Spring and a substitution line of Besostaya I 4B into Cappelle-Desprez. The calli from these lines were found to differ in their growth rates and morphogenic and regenerative activities. The substitution of different 4B chromosomes into Chinese Spring significantly increased morphogenesis and shoot regeneration from callus. The potential for developing wheat lines with improved culture characteristics is discussed.
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  • 34
    ISSN: 1432-2242
    Keywords: Ornithine decarboxylase ; Chicken ; Muscle ; Genetics ; Growth differences
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    Topics: Biology
    Notes: Summary Little is known about the biochemical correlates of selection for growth in farm or laboratory animals, or the identity of the gene products affected or produced by ‘trait-genes’. Modern broiler chickens have about 8-fold greater breast muscle mass than layer chickens at 7 weeks of age and over 2-fold greater breast muscle mass than their 1972 counterparts. This increase in muscle mass is associated with over 20-fold higher levels of ornithine decarboxylase (ODC) in broiler chickens at 1 week of age as compared with layer strain chickens; there is a comparable increase in a relaxed-selection strain of broilers. The increase in ODC levels is larger than the differences in muscle or body weight between broilers and layers at 7 weeks of age, occurs at an age when there is no difference in weights between the strains and precedes the major growth spurt. Increases in ODC levels and hence polyamine synthesis have been associated with, and usually precede, rapid growth and cell proliferation in a wide range of cell types and organisms in response to many different stimuli. Therefore, the correlation of ODC levels with genetic differences in muscle growth make it worth investigating the control of ODC gene expression in these strains.
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  • 35
    ISSN: 1432-2242
    Keywords: Taxonomy ; Germplasm identification ; Varietal identity ; Environmental interaction ; Genetics ; Multivariate analysis
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    Notes: Summary Separations of kafirin and alcohol soluble glutelin proteins by reversed-phase high-performance liquid chromatography (RP-HPLC) from 7 inbreds and one hybrid of sorghum [Sorghum bicolor (L.) Moench] and one source of Johnsongrass [Sorghum halapense (L.) Pers.] were compared. Objectives were to assess the stability of protein profiles for seed sources produced at different locations and in different environments to examine the potential of RP-HPLC to provide genotypic profiles for sorghum. Analyses of variance data showed that levels of variation due to environments and locations were small; the majority of variation (93%) was among genotypes. Associations among inbreds revealed by multivariate and cluster analysis showed similarity with those that would be expected on the basis of pedigree. A chi-square analysis showed no deviation in the hybrid profile from the expected 2∶1 ratio of peaks from the female and male inbred parents, respectively. Improvements in the ability to correctly assign common peaks are necessary before associations among numerous sorghum genotypes can be reliably demonstrated by analysis of data from reversed-phase high-performance liquid chromatography (RP-HPLC).
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    Theoretical and applied genetics 76 (1988), S. 405-410 
    ISSN: 1432-2242
    Keywords: Zea mays ; Haploid induction ; Gynogenesis ; Genetics ; Inducer line
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The effect of genotype on maternal haploid plant production in maize was studied. The frequency of gynogenetic plants when “Stock 6” was used as pollinator varied according to the female parent genotype. No simple relation was observed between genotypic aptitudes for gynogenetic and androgenetic development, which occured after pollination of “W23” plant carrying the “indeterminate gametophyte” gene. Furthermore, the population NS, a favorably responsive genotype to anther culture, does not exhibit exceptional ability for in vivo gynogenesis. The effect of inbreeding and the influence of maternal haploid origin suggest that specific genes control maternal haploid initiation and development. However, gynogenetic development is not limited to a particular genotype. The frequency of maternal haploids may be increased by using specific pollen parents. Attempts were made to select for a high haploidyinducing trait and the present study reports the successful development of lines that can be utilized as pollen parents to induce haploids for experimental purposes and breeding programmes. When an inbred line “WS14”, derived from the cross W23 x Stock 6, was used as pollen parent, 2%–5% maternal haploids were obtained according to the female parent genotype. A high haploidy-inducing potential is a heritable trait and may be controlled by a limited number of genes. Genetic determination of the haploidy-inducing character was examined in relation to the efficiency of the selecting method and the mechanisms involved in the origin of maternal haploids.
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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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    Cell & tissue research 255 (1989), S. 385-391 
    ISSN: 1432-0878
    Keywords: Myogenesis ; Muscle regeneration ; Genetics ; Autoradiography ; Tritiated thymidine ; Mouse (Swiss;BALBc)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Muscle precursor replication in Swiss mice, in which muscle regeneration is exceptionally vigorous, was compared with previous data for regeneration in BALBc mice. The tibialis anterior muscles of 23 male and 15 female inbred Swiss SJL/J mice were crush injured, and tritiated thymidine injected into mice at various times after injury to label replicating muscle precursors. Lesion samples were taken 10 days after injury, processed for autoradiography, and grain counts of myotube nuclei analysed. Muscle regeneration was more vigorous in male compared with female Swiss mice, and in both was strikingly greater than that in BALBc mice in which there was extensive fibrous connective tissue throughout the lesions. Autoradiographic analysis showed that muscle precursor replication started at 24 hours in Swiss mice, 6 hours earlier than the onset at 30 hours in BALBc mice. Muscle precursor replication appeared to be more active 96 hours after injury in female Swiss compared with male BALBc and male Swiss mice respectively, although numbers of precursor cells replicating at other times were similar. It is not known whether the slight difference in onset of muscle precursor replication can alone account for the more complete muscle regeneration seen in Swiss mice. Similar studies were carried out in 11 male and 10 female F1 hybrid (SJL/J x BALBc) mice. Analysis of labelled myotube nuclei showed that muscle precursors did not synthesise DNA prior to 30 hours after injury, and regeneration resembled that of the parental BALBc strain.
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  • 40
    ISSN: 1617-4623
    Keywords: E. coli ; Genetics ; Polysaccharide biosynthesis ; Secretion
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    Topics: Biology
    Notes: Summary Transposon and deletion analysis of the cloned K1 capsule biosynthesis genes of Escherichia coli revealed that approximately 17 kb of DNA, split into three functional regions, is required for capsule production. One block (region 1) is required for translocation of polysaccharide to the cell surface and mutations in this region result in the intracellular appearance of polymer indistinguishable on immunoelectrophoresis to that found on the surface of K1 encapsulated bacteria. This material was released from the cell by osmotic shock indicating that the polysaccharide was probably present in the periplasmic space. Insertions in a second block (region 2) completely abolished polymer production and this second region is believed to encode the enzymes for the biosynthesis and polymerisation of the K1 antigen. Addition of exogenous N-acetylneuraminic acid to one insertion mutant in this region restored its ability to express surface polymer as judged by K1 phage sensitivity. This insertion probably defines genes involved in biosynthesis of N-acetylneuraminic acid. Insertions in a third block (region 3) result in the intracellular appearance of polysaccharide with a very low electrophoretic mobility. The presence of the cloned K1 capsule biosynthesis genes on a multicopy plasmid in an E. coli K-12 strain did not increase the yields of capsular polysaccharide produced compared to the K1+ isolate from which the genes were cloned.
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  • 41
    ISSN: 1617-4623
    Keywords: NAD metabolism ; Regulation ; nadR ; Salmonella typhimurium ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The nadR locus (99 min) controls the transcription of several genes involved with either the biosynthesis (nadAB) or recycling (pncB) of NAD in Salmonella typhimurium. Point mutations in this locus were found to cause defects either in the transport of nicotinamide mononucleotide (PnuA-), the regulation of nadAB (NadR-) or both transport and regulation (PnuA-NadR-). Deletions or insertions into nadR always resulted in the PnuA- NadR- phenotypes. Merodiploids constructed with various combiminations of PnuA-, NadR- or PnuA-NadR- strains indicate a single complementation group. The results suggest the NadR product is a bifunctional regulatory protein. Operon fusions to lacZ (nadR:: Mud1-8) were used to show that nadR is not autoregulated and is transcribed in a clockwise direction. The gene was also cloned and located within a 2 kb EcoR1-BglII fragment.
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  • 42
    ISSN: 1617-4623
    Keywords: Nicotiana plumbaginifolia ; Nitrate reductase ; Genetics ; Molybdenum cofactor biosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A total of 70 cnx mutants have been characterized from a collection of 211 nitrate reductase deficient (NR-) mutants isolated from mutagenized Nicotiana plumbaginifolia protoplast cultures after chlorate selection and regeneration into plants. They are presumed to be affected in the biosynthesis of the molybdenum cofactor since they are also deficient for xanthine dehydrogenase activity but contain NR apoenzyme. The remaining clones were classified as nia mutants. Sexual crosses performed between cnx mutants allowed them to be classified into six independent complementation groups. Mutants representative of these complementation groups were used for somatic hybridization experiments with the already characterized N. plumbaginifolia mutants NX1, NX24, NX23 and CNX103 belonging to the complementation groups cnxA, B, C and D respectively. On the basis of genetic analysis and somatic hybridization experiments, two new complementation groups, cnxE and F, not previously described in higher plants, were characterized. Unphysiologically high levels of molybdate can restore the NR activity of cnxA mutant seedlings in vivo, but cannot restore NR activity to any mutant from the other cnx complementation groups.
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    Molecular genetics and genomics 205 (1986), S. 507-514 
    ISSN: 1617-4623
    Keywords: Pyridine nucleotide cycle ; NAD metabolism ; Salmonella typhimurium ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A series of Mud1 and Tn10 insertions were identified in the pncA chromosome region of Salmonella typhimurium which is responsible for the production of nicotinamide deamidase. Both pncA (resulting in no nicotinamide deamidase activity) and pncX (resulting in lowered nicotinamide deamidase activity) insertions were constructed. In addition, mutants which could utilize nicotinamide as a sole source of nitrogen were isolated. These mutants, designated pncH, hyperproduce nicotinamide deamidase. Genetic studies utilizing pncX-lacZ and pncA-lacZ operon fusions indicate that pncX::Tn10 insertions reduce transcription of pncA-lac while pncH mutations increase the expression of both pncA-lacZ and pncX-lacZ. The gene order was determined as purB-pncA-pncX-gdh with transcription of both pncA and pncX occurring in the counterclockwise direction. Merodiploid studies suggest a model whereby pncX and pncA form an operon with the major promoter occurring upstream from pncX. A second, weaker promoter for pncA must be situated between pncX and pncA. The pncH mutations appear to occur in the pncX promoter (pncXp) increasing promoter activity.
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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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    International journal of anthropology 2 (1987), S. 141-149 
    ISSN: 1824-3096
    Keywords: Absolute finger ridge count ; Genetics ; Dermatoglyphics ; India ; Major gene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In order to test the hypothesis of a major gene effect on absolute total finger ridge count (ATFRC), the nature of relationship between mean ATFRC and its variability was evaluated in a series of 47 population samples from India. Regression analysis showed that both the standard deviation and the coefficient of variation are significantly related to mean ATFRC, and about 35% of the variation in ATFRC is explained by the dependent variable coefficent of variation. These results support the hypothesis of a major gene effect on the trait ATFRC.
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  • 46
    ISSN: 0032-8332
    Keywords: Saimiri ; Human-type ABO blood groups ; Genetics ; Colony management
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The human-type ABO blood groups were determined for 94 families of the squirrel monkey which included 151 animals. Four phenotypes of ABO blood groups (A, B, AB, and O) were detected. Family analysis revealed that the human-type ABO blood groups in this species were governed by three alleles, codominantA andB and silentO. There were intraspecific differences in the distribution of phenotypes and gene frequency among three populations imported by different routes at different times. The usefulness of ABO blood groups for defining the genetic variability of a squirrel monkey breeding colony through successive generations is discussed on the basis of the difference in distribution of ABO blood groups between wild-originated parental and its first colony-born populations.
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  • 47
    ISSN: 1617-4623
    Keywords: Aspergillus ; Genetics ; Transformation ; trpC lacZ gene fusion ; Gene replacement
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Aspergillus niger tryptophan auxotrophic mutants have been isolated after UV irradiation of conidiospores. The mutants belong to two different complementation groups, trpA and trpB, which complement each other in heterokaryons. Neither of the mutations could be complemented with the cloned A. niger trpC gene. To obtain A. niger trpC mutants in a direct way, gene inactivation by cotransformation was performed. For this purpose an in-frame gene fusion between the A. niger trpC and Escherichia coli lacZ genes was constructed and shown to be functionally expressed after introduction into A. niger by cotransformation with the pyrA gene as selective marker. Among the β-galactosidase expressing cotransformants, obtained with either circular or linearized vectors, no trpC mutants were detected, even after enrichment. Such mutants, however, could be obtained by cotransformation of A. niger with specific fragments of the fusion gene. Biochemical analysis of the cotransformants indicated that in nearly all cases the fusion gene had replaced the wild-type trpC gene. Genetic analysis showed that the trpC mutation is not linked to any of the A. niger loci described so far. The trpC mutants can be complemented by the cloned A. niger trpC gene as well as by the A. nidulans trpC gene.
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  • 48
    ISSN: 1573-5133
    Keywords: Adaptation ; Dam ; Enzymes ; Electrophoresis ; Evolution ; Genetics ; Physiology ; Regulated streams ; Thermal maximum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Critical thermal maxima (CTM) and genetic variation were compared for red shiners, Notropis lutrensis, from regulated and unregulated sites on the Brazos River in northcentral Texas. Tailwater fish acclimated to 25°C had significantly lower CTM's than those from a site upstream from the dam and unregulated downstream sites. Significantly different intrasite variances were observed, with two- and four-fold larger CTM variances in fish from within 1 km and 30 km of the dam. Genetic variation was determined from electrophoretic comparisons at 21 structural gene loci. Mean heterozygosity was greatest at regulated sites. Tests for locus heterogeneity at five variable loci indicated that regulated and unregulated populations are not homogeneous. Fish under regulation were genetically more similar to each other than they were to those not affected by regulation. The proportions of the gene variance attributable to habitat alteration were partitioned, and fully one-third of the gene variation was attributed to stream regulation. Patterns of variation in thermal tolerance and metabolic enzymes in the red shiner correlated closely with temperature regimes associated with hypolimnion release from the dam. These adaptive responses have occurred in less than 40 years.
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    Environmental biology of fishes 18 (1987), S. 249-256 
    ISSN: 1573-5133
    Keywords: Developmental rate ; Genetics ; Inheritance ; Meristic ; Salmonidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Deviations from morphological intermediacy in six first generation hybrids between three hatchery strains of rainbow trout, raised in a common environment, are reported. Hybrids have higher mean counts of four meristic characters than their maternal parental strain in a significantly greater number of cases (18 out of 24). Furthermore, eight of eleven hybrid indices are not intermediate. These results are discussed in reference to several mechanisms and models proposed to account for observed responses of meristic characters to environmental and genetic influences.
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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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    Plant and soil 89 (1985), S. 199-226 
    ISSN: 1573-5036
    Keywords: Ecology ; Genetics ; Physiology ; Salt tolerance ; Tomato species
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary An interdisciplinary approach to breeding for stress tolerance in plants has gained considerable recognition in the past few years. Accordingly, this article presents a synthesis of the genetic, physiological, and ecological aspects of salt tolerance in plants. An understanding of these aspects and the interrelationships between them is essential for an efficient breeding program. A significant part of the presentation concentrates on the basic problems associated with the genetics of tolerance to stresses and of quantitative characters in general, since many of the unsolved problems relevant to the genetics of salt tolerance are still general. Significant progress in the breeding of quantitative as well as qualitative traits in multicellular organisms depends on an understanding of the genetic and epigenetic dimensions of gene action. The discussion therefore includes an overview of (1) the limited existing knowledge on the genetic control of salt tolerance and (2) the physiological mechanisms and molecular targets central to the control of salt resistance as expressed by the amount and stability of yield. An additional subject emphasized here concerns the main strategies of adaptation of wild species to their natural habitats. An understanding of them is essential to (1) enable distinction between traits that can increase agricultural yield and traits that are favorable only for survival under natural conditions (such a distinction is essential, especially when wild species are used as a gene source), and (2) predict the best combinations of characters for efficient agricultural production in stressful environments.
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    Plant and soil 90 (1986), S. 429-453 
    ISSN: 1573-5036
    Keywords: Actinorhizae ; Frankia ; Genetics ; Nitrogen fixation ; Nodulation ; Symbiosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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    Developmental Genetics 2 (1981) 
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
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  • 55
    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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    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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    Developmental Genetics 2 (1981) 
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    Keywords: Life and Medical Sciences ; Genetics
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  • 58
    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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    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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    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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    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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    Developmental Genetics 3 (1982), S. 273-273 
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
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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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    Developmental Genetics 3 (1982), S. 371-372 
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
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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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    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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    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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    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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    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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    Developmental Genetics 4 (1983), S. 355-378 
    ISSN: 0192-253X
    Keywords: courtship ; learning ; biological rhythms ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Reproductive behavior in Drosophila involves a complex series of actions which is perturbed by many different kinds of mutations. Some of the most interesting courtship variants are those originally isolated with respect to disruptions of general learning and memory. Several types of genetically abnormal males have their “conditioned courtship” blocked or attenuated by the learning and memory mutations, some of which, in turn, are known to cause abnormal levels of specific monoamines or cyclic nucleotides. Recent studies of the defective courtship performed by the conditioning mutants involve “mosaic focusing” of the neural tissues affected by the behavioral/biochemical mutations. These experiments address the question of whether there are localized influences of the relevant genetic loci in their control of conditioned courtship, in spite of the fact that the protein products of the genes have a broad tissue distribution. Female responses to courting Drosophila males can also be dependent on the former's prior experiences. This pertains to enhancing aftereffects of prestimulation by the courtship song that is produced by a male; and the same learning and memory mutations, expressed in females, impinge on the normal aftereffects. One element of acoustical communication in courtship is a rhythmic oscillation in a particular component of the song. This short-term behavioral rhythm is altered in males expressing circadian rhythm mutations. To investigate the neural and cellular mechanisms by which these genes act, a mosaic analysis has been initiated on the ganglia affected by a clock mutation in its disruption of the courtship rhythm and of circadian cycles. A molecular isolation and identification of the normal form of this genecalled period - has also begun, in order to probe the locus's structure and function in detail. Such an investigation will include a comparison of the mosaic results with a direct determination of the various tissues in which the gene's product is expressed. In addition, interspecific transfers of the purified period gene will augment the current studies of species-specific features of the rhythmic courtship songs.
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    Developmental Genetics 4 (1983), S. 425-438 
    ISSN: 0192-253X
    Keywords: polymorphism ; enzyme ; control gene ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: A study was made of environmental and genetic factors affecting the quantity and disposition of the alcohol dehydrogenase (ADH) protein in Drosophila melanogaster. It was found that the amount of enzyme per fly is greatly influenced by the environmental conditions in which it develops. A critical factor is the concentration of yeast in the medium. A high concentration of yeast can double the quantity of ADH. The yeast appears to act through the provision of protein, and the protein to act through the provision of threonine, which is already known to induce ADH in fungi.Various genetic factors affect the quantity of enzyme. Males have more ADH than females. Files homozygous for the Fast allele have more ADH than those homozygous for the slow allele, and the difference is greater in females than in males. One particular line (ve), homozygous for Slow, has approximately half the normal quantity of enzyme, and the quantity segregates with the electrophoretic allele. Lines differ in the relative amounts of ADH in the gut (including Malpighian tubules) and the fat body. In general it seems that slow lines have relatively more enzyme in the fat body. In a cross between ve and a line homozygous to Fast, the difference in tissue distribution segregated with the electrophoretic allele. It is argued, but not demonstrated, that the differences in quantity and tissue distribution are due to nucleotide substitutions in noncoding regions close to, or within, the structural gene.It seems likely that the observed environmental and genetic differences in the quantity and disposition of ADH will influence the relative selective values of the electrophoretic genotypes.
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    Developmental Genetics 4 (1983), S. 407-424 
    ISSN: 0192-253X
    Keywords: selection ; enzyme ; control-gene ; DNA polymorphism ; Drosophila ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The control of alcohol dehydrogenase (ADH) activity in natural populations of Drosophila melanogaster is chromosomally diverse and due to variation in allotype, enzyme level, and possibly post-translational modification. A comparative study of evolution in Adh structural gene variations with those loci modifying ADH expression has been carried out in large model populations maintained in environments that varied in temperature and food. Broadly based measures of gene expression were obtained as ADH activity and ADH protein level (determined immunologically) from individual flies whose allotype was also determined. The response to selection by “regulatory” or modifier loci compared with ADH allotypes was found to vary with environment, and its direction was not necessarily predictable from the kinetic properties of allele products. Selection for dominance modification of ADH activity in relation to Adh allotype was also observed. Analysis of genotype-environment interaction discerned two main types of response. Two major classes of chromosomal types, identified from restriction endonuclease map variations in a 12-kb region of DNA containing the Adh transcriptional unit, were present in the population. These two types of chromosome were in turn associated with the two types of interaction between genotypes and the environment. The results implicate polylmorphism for the control of genotypeenvironment interaction in populations, a genetically complex unit of selection, and a degree of evolutionary independence between structural and regulatory genes.
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    Developmental Genetics 5 (1984), S. 1-25 
    ISSN: 0192-253X
    Keywords: maize ; endosperm ; mutants ; Life and Medical Sciences ; Genetics
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  • 74
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    Developmental Genetics 4 (1983) 
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    Keywords: Life and Medical Sciences ; Genetics
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    Developmental Genetics 4 (1983), S. 229-230 
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
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  • 76
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    Developmental Genetics 6 (1985) 
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    Keywords: Life and Medical Sciences ; Genetics
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    Developmental Genetics 6 (1985), S. 39-58 
    ISSN: 0192-253X
    Keywords: Drosophila melanogaster ; trisomy 3L ; dosage compensation ; heat shock ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Production of trisomic-3L Drosophila melanogaster has allowed further investigation of compensated levels of gene expression in autosomal trisomies. We find that four enzyme loci on this arm produce diploid levels of gene product in trisomic-3L larvae. For one of these genes, we show that all three alleles are expressed at similar levels. Two genes on 3L display dose-dependent levels of gene product, and their location, relative to the four compensating loci, indicates that these two classes of genes are not regionally separated. In trisomic-2R larvae, the level of enzyme produced from on 2R-linked gene was dose dependent. In contrast, measurements of five loci on the X chromosome in metafemales (X trisomies) suggest that most genes are compensated in these individuals. Heat-shock gene expression in trisomic-3L salivary glands was qualitatively similar to diploids. The quantities of the small hsps (from the 67B cluster on 3L) suggest that these four genes respond independently to the trisomic condition; two produce compensated levels of protein, whereas the other two produce dose-dependent levels of protein. The amount of hsp 83 produced in trisomies was similar to diploids (compensated). However, quantification of hsp 83 RNA showed that a dose-dependent level of transcript was produced. This implies that hsp 83 compensation is controlled post-transcriptionally.
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    Developmental Genetics 6 (1985), S. 93-100 
    ISSN: 0192-253X
    Keywords: heat shock ; phenocopy ; forked ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Heat shock uncovers the recessive forked phenotype when heterozygotes between f36a and wild-type are heated during sensitive periods in pupal development. We call the phenocopy of a mutant in such a heterozygote a heterocopy. The heterocopy in f36a/+ is virtually identical to the mutant phenotype; however, bristles on different parts of the body are affected during different sensitive periods. We discuss the hypothesis that the heat shock acts by affecting expression of the wild-type gene product corresponding to the mutant gene. The sensitive period for heterocopy induction in a specific tissue is proposed to correspond to the normal time of gene expression for the forked gene product in a particular tissue.
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    Developmental Genetics 6 (1985), S. 151-151 
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
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  • 80
    ISSN: 0192-253X
    Keywords: Dictyostelium discoideum ; revertants of stmF mutants ; cGMP metabolism ; cGMP-specific phosphodiesterase ; suppressor mutations ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: stmF mutants of Dictyostelium discoideum produce long, banded aggregation streams on growth plates and exhibit altered cGMP metabolism. To learn more about the role of cGMP in chemotaxis and the nature of the defect in these mutants, 15 nonstreaming (Stm+) revertants of two stmF mutants were isolated and characterized. Fourteen of the revertants continued to show the elevated cAMP-induced cGMP response and very low cGMP-specific phosphodiesterase (cGPD) activity characteristic of their stmF parents. Parasexual genetic analysis revealed that many of these Stm+ revertants carried phenotypic suppressors unlinked to stmF. One Stm+ revertant, strain HC344, exhibited a low, prolonged cGMP response and relatively high cGPD activity throughout development. To determine whether the elevated cGPD activity in this revertant resulted from increased enzyme production or enhanced enzyme activity, cGPDs were partially purified from the wild-type strain, the stmF parent and revertant HC344, and properties of the enzymes were compared. cGPDs from the stmF mutant and the revertant showed similar differences from the wild-type enzyme in kinetic properties, thermal stability, and sensitivity to certain inhibitors. These results suggest that stmF is the structural gene of the cGPD. In addition, the unusual cGMP response in revertant HC344 appeared to be due to increased production of an altered cGPD.
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    Developmental Genetics 6 (1985), S. 213-238 
    ISSN: 0192-253X
    Keywords: ciliate pattern formation ; expression of mutations ; Tetrahymena thermophila mutations ; reversals of symmetry ; spatial organization of cell surface ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The initial changes of cell-surface organization that occurred as the recessive janAl (janus) mutation of Tetrahymena thermophila first became expressed were elucidated in a special mating scheme in which old macronuclei homozygous for janA+ were synchronously replaced by new macronuclei homozygous for janAl. During this period of onset of expression, the number, regularity, and asymmetry of the ciliary rows remained unchanged. New normal (primary) oral apparatuses (OAs) continued to be formed posterior to old OAs, as in normal cells. At about four fissions after conjugation, abnormal (secondary) OAs with a partial reversal of asymmetry began to appear nearly opposite to the primary OAs, close to but not at the eventual circumferential position of janAl secondary OAs. The array of contractile vacuole pores (CVPs), normally located adjacent to two ciliary rows centered near 22% of the cell circumference to the righ of the primary oral meridian, underwent a two-step transformation: first, the number of adjacent ciliary rows bearing CVPs increased to 3, 4, and sometimes 5, then “skipped” rows appeared within this broadened CVP-arc to split the single set of CVPs into two separated subsets. The CVP transformations occurred gradually and progressively. They began prior to the expression of secondary OAs but accelerated as secondary OAs appeared. As the CVP are became broader, its midpoint shifted somewhat to the right, away from the primary oral meridian, but ended up close to halfway between the primary and secondary oral meridians. The data provide a better fit to an intercalation model than to an alternative double gradient model, suggesting that the janAl mutation alters the large-scale organization of positional values by preventing the expression of a subset of these values and thus provoking reverse-intercalation of the remainder.
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    Developmental Genetics 6 (1985), S. 293-293 
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    Keywords: Life and Medical Sciences ; Genetics
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    Developmental Genetics 6 (1985), S. 297-297 
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    Keywords: Life and Medical Sciences ; Genetics
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  • 84
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    Developmental Genetics 7 (1986) 
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
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  • 85
    ISSN: 0192-253X
    Keywords: Drosophila ; temperature effects ; heat-shock ; cell-lethal mutation ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Pulses of various durations at temperatures between 29 and 38°C were applied to developing larvae of Drosophila melanogaster carrying the temperature-sensitive cell-lethal mutation 1 (1)ts726. The results show that it is not possible to reduce the time required for the induction of abnormalities in the mutant by treating larvae with heat pulses at temperatures higher than 29°C. Instead, treatment with high temperature leads to fewer abnormalities than 29°C treatments. Furthermore with high temperature treatments, the mutation has less effect on viability than is seen at 29°C. It is suggested that 1 (1)ts726 leads to abnormalities and death by a temperature-induced imbalance between different physiological or development events, rather than by interfering with the ability of the cell or the organism to withstand high temperature in general.
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    Developmental Genetics 6 (1985), S. 59-74 
    ISSN: 0192-253X
    Keywords: Dictyostelium discoideum ; cell cohesion ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Three stage-specific cohesive systems operate in D. discoideum: VEG, elaborated by vegetative cells: AR, by aggregation competent cells; and PAR, by post aggregation stage cells. Previous study of a mutant strain JC-5 had shown the stability of its PAR system (but not the AR) to be temperature sensitive. However, the phenotypic expression of this mutation termed Coh A is complicated by the presence in that strain of a preexisting mutant gene Rde A, which accelerates developmental events generally and alters the pattern of morphogenesis. Genetic evidence presented here indicates that the two mutations have been separated by parasexual recombination yielding a Coh A, Rde A+ segregant class of which strain JC-36 is a prototype.At the permissive temperature, JC-36 follows a morphogenetic sequence like that of the wild type in respect to timing, morphogenetic pattern, and spore appearance. At the restrictive temperature, it forms normal aggregates at the usual time but exhibits two morphogenetic aberrancies during post aggregative development. First, fruit construction is arrested at a stage approximating the 16 hr “Bottle” stage of the wild type, though more squat and blunt tipped, and then the aggregate regresses. Cytodifferentiation into spores and stalk cells is also blocked. Second, a shift of slugs migrating normally at the permissive temperature to the restrictive causes the latter to disintegrate progressively as they leave clumps of cells behind them within the flattened sheath.JC-36 cells developing at the restrictive temperature also exhibited a decrease in EDTA resistant cohesivity attributable on two grounds to the sensitivity of the PAR system. In addition, the disappearance of the AR system completed in the wild type by the Mexicanhat (18-19 hr) stage is indefinitely arrested at an intermediate level in JC-36.
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    Developmental Genetics 6 (1985), S. 113-132 
    ISSN: 0192-253X
    Keywords: eliminated DNA ; facultatively persistent sequences ; macronuclear development ; Tetrahymena thermophila ; phenotypic assortment ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: During conjugation in the ciliated protozoan, Tetrahymena thermophila, a somatic MAC-ronucleus develops from the germinal MICronucleus. Ten to 20 percent of the MIC genome is eliminated during this process. Three repetitive families have been identified which have different levels of repetition in the MIC and are eliminated to different degrees in the MAC. Some members of two of these families persist in the MAC. In this study, we have looked at these persistent sequences in the MAC of cell lines from a variety of sources including several inbed strains, two sets of caryonides, caryonidal subclones, and vegetatively aged cell clones. The results suggest that the sequences that remain in the MAC have a genetic predisposition to persist. However, epigenetic variations occur as the MAC develops so that only some of the persistent sequences are actually observed in a particular MAC. Polymorphisms may be generated if alternative processing of a single MIC segment occurs. These polymorphisms can later be resolved by phenotypic assortment during vegetative growth. These facultatively persistent sequences appear to differ from sequences previously described in this organism.
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  • 88
    ISSN: 0192-253X
    Keywords: ecdysteroid ; prothoracic gland ; temperature sensitive ; Drosophila ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The dominant temperature-sensitive mutation L(3)3DTS (DTS-3) in Drosophila melanogaster causes lethality of heterozygotes during the third larval instar at the restrictive temperature (29°C). Temperature-shift experiments revealed two distinct temperature-sensitive periods, with lethal phases during the third larval instar (which may persist for 4 weeks) and during the late pupal stage. At 29°C mutant imaginal discs are unable to evert in situ, but did evert normally if cultured in the presence of exogenous ecdysterone or when implanted into wild-type larval hosts. The only morphologically abnormal tissue present in the lethal larvae is the ring gland, the prothoracic gland being greatly hypertrophied in third instar DTS-3 larvae. Injection of a single wild-type ring gland rescued these mutant larvae, indicating that the mutant gland is functionally, as well as morphologically, abnormal. Finally, the mutant larvae were shown to have less than 10% of the wild-type ecdysteroid levels. These results are all consistent with a proposed lesion in ecdysteroid hormone production in DTS-3 larvae. A comparison with the phenotypes of other “ecdysone-less” mutants is presented.
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    Developmental Genetics 8 (1987), S. 35-43 
    ISSN: 0192-253X
    Keywords: development ; isozymes ; murine trisomy ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: We examined developmental changes in the relative activities of three different isozyme systems: aldolase, enolase and phosphoglycerate mutase, in tissues of fetal mice with trisomy 16 and of fetal euploid littermates. We wanted to determine whether morphological abnormalities such as reduced weight and size, which are generally observed in murine trisomy, are reflected at the molecular level. Following electrophoretic separation and subsequent measurement of relative activities of enolase isozymes in brain and phospho-glycerate mutase isozymes in heart, we found no significant differences between trisomy 16 fetuses and their euploid littermates. Synthesis of liver-specific aldolase was, however, delayed in trisomy 16 fetuses.
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    Developmental Genetics 8 (1987), S. 83-89 
    ISSN: 0192-253X
    Keywords: chick blastula ; hypoblast-epiblast interaction ; transcriptional control ; α-amanitin ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Interaction between the epiblast and the primary hypoblast in chick blastula results in induction of the primitive streak (PS) in the epiblast. Alpha-amanitin, a specific inhibitor of poly A-containing RNA synthesis, inhibits formation of the definitive PS. This inhibition is associated with qualitative changes in the pattern of protein synthesis in the hypoblast but not in the epiblast. The protein pattern of the component areas of the epiblast shows increase in some polypeptides after treatment with α-amanitin. By contrast, α-amanitin resulted in a decrease in synthesis of several polypeptides, which are either undetectable or weakly present in the hypoblast. The α-amanitin-sensitive translational products of the embryonic genome that are observed in the hypoblast may have specific functions in the control of PS induction and stabilization.
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    Developmental Genetics 8 (1987), S. 121-122 
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    Keywords: Life and Medical Sciences ; Genetics
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    Developmental Genetics 8 (1987), S. 99-119 
    ISSN: 0192-253X
    Keywords: Drosophila ; tissue polarity ; frizzled ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The epidermis of Drosophila has a tissue polarity that is manifested by a parallel array of polarized structures (primarily hairs and bristles). The production of normal tissue polarity requires the function of the frizzled (fz) locus. We have isolated a large number of alleles at this locus and have phenotypically characterized more than 25 of them. We have found extensive allelic variation that a previous study failed to detect. Most of the alleles fall into a hypomorphic to amorphic series. Two alleles, however, have unusual properties. These alleles, which in general are moderately strong alleles, fail to produce a rough eye phenotype that is characteristic of all the other moderate or strong fz alleles. Thus, these two alleles are tissue specific in effect. Furthermore, these two alleles also have a neomorphic or antimorphic effect on hair polarity in one region of the wing.
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    Developmental Genetics 8 (1987), S. 165-177 
    ISSN: 0192-253X
    Keywords: embryonic antigen ; tumor mutants ; oncodevelopmental molecule ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The 63-kDa antigen recognized by the monoclonal antibody F7D6 is present in all Drosophila embryonic cells and disappears from most tissues as each one reaches its final, differentiated state. Larval tissues lose the antigen around the time of hatching, imaginal tissues lose it during metamorphosis, and germ cells lose it during gametogenesis (Bedian et al: Devel Biol 115:105-118, 1986). The nervous system and spontaneously contracting musculature of the gut and gonads are exceptions and remain antigen positive at all stages. The F7D6 antigen appears to be associated with dividing, undifferentiated cells and electrogenic cells. This prompted us to test tumors for antigen presence. We tested four different recessive mutants that give rise to four different types of tumorous transformation: the embryonic tumor Notch, several larval melanotic tumors, the imaginal disc tumor 1(2)gl, and three alleles of the ovarian tumor otu. In all cases, tumorous tissues in homozygotes contained the F7D6 antigen. The electrophoretic mobility of the antigen appeared to be unaltered in tumorous tissues compared to normal cells, but the antigen is expressed at higher levels. The antigen is found on the cytoplasmic surface of plasma membranes and appears to be a marker of undifferentiated normal and tumorous cells. Similarities and differences between the F7D6 antigen and Drosophila c-src protein are discussed.
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    Developmental Genetics 8 (1987), S. i 
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    Keywords: Life and Medical Sciences ; Genetics
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  • 95
    ISSN: 0192-253X
    Keywords: microinjection ; familial amyloidotic polyneuropathy ; fertilized egg ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: To analyze the regulation of transthyretin gene expression we have produced transgenic mice by microinjecting cloned human transthyretin genes into fertilized eggs of C57BL/6 mice. The 7.6-kilobase (kb) human transthyretin gene containing about 500 base pairs (bp) in the upstream region was used for microinjection. Seven out of nine transgenic mice had detectable amounts of human transthyretin in serum when analyzed by enzyme-linked immunosorbent assay.Transthyretin mRNA was detected in liver and yolk sac but not in other tissues including brain. The amount of mRNA was variable among transgenic mice and was about one-tenth of mouse endogenous transthyretin mRNA. Human and mouse transthyretin mRNAs were detected in liver of fetus and yolk sac at 13 days of gestation and unlike yolk sac the level of mRNA in liver increased gradually during development and reached the maximum at around 17 days of gestation. Human transthyretin was associated with mouse transthyretin to form tetramers as judged from the dilution curve of enzyme-linked immu-nosorbent assay and the spur formation in Ouchterlony assay.
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    Developmental Genetics 8 (1987), S. 281-293 
    ISSN: 0192-253X
    Keywords: mouse ; human ; cow ; maps ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Technological advances in the 1970s encouraged the mapping of homologous gene loci in different mammalian species, including mouse and man. One hundred eighty-five homologous loci have now been mapped in these two species. Conservation of linkage is sufficient to identify substantial segments of the two genomes that have been left intact since their divergence from a common ancestor. The recognition of these conserved segments allows experimental manipulation of mouse chromosomes or chromosomal regions to produce models of human chromosomal anomalies of medical importance.Comparative gene mapping has been extended beyond mouse and man and the genomes of some species, including domestic cattle, appear to be more highly conserved relative to humans than the mouse. Such species may be particularly useful in providing models of human chromosomal anomalies that cannot be duplicated in laboratory mice.
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    Developmental Genetics 9 (1988), S. 23-35 
    ISSN: 0192-253X
    Keywords: maternal-specific transcripts ; genomic clones ; developmental RNA expression ; in situ chromosomal localization ; embryogenesis ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The unique cellular and genetic events which occur during the first few hours of Drosophila embryogenesis suggest that there are genes whose function is entirely or largely limited to this stage; this is supported by both genetic and molecular evidence. To identify some of these genes and characterize the relative contribution of specifically maternal and specifically zygotic transcription to early embryogenesis, we used competition and differential screening of a Drosophila genomic DNA library to obtain blastoderm- and maternal-differential sequences [Roark et al.: Dev Biol 109:476-488, 1985]. We describe here the Eco RI restriction fragments, chromosomal location, and size and developmental pattern of expression of the RNAs transcribed from 19 maternal-differential sequences. Five sequences encode maternal-specific transcripts (50-150-fold more abundant in maternal RNA than at any other stage). The maternal-specific and maternal-differential sequences are located at single sites on all major chromosome arms. Comparison of these sites with the sites of presently mapped maternal-effect genes shows several possible correlations, including one region containing three maternal-effect lethal mutations and two maternalspecific sequences.
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    Developmental Genetics 9 (1988), S. 69-69 
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    Keywords: Life and Medical Sciences ; Genetics
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    Developmental Genetics 9 (1988) 
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    Keywords: Life and Medical Sciences ; Genetics
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    Developmental Genetics 8 (1987), S. 91-98 
    ISSN: 0192-253X
    Keywords: wing size ; miniature ; cell size ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: To elucidate the mechanisms whereby genes and environment influence wing size, we investigated the effects of various rearing temperatures and larval crowding conditions on the wings of the mutant miniature and wild-type fruit flies. In adults we monitored wing size, cell number, wing thickness, cell density; in larval imaginal discs we looked for cell death. Cell density was inversely proportional to wing size. Of particular interest was the finding that smaller wings tend to be thicker. Electron microscope studies showed that the miniature wing layers are grossly abnormal. We hypothesize that these abnormalities are due to abnormal cell flattening of the wing epithelial cells, and we conclude that gene and environmental effects on cell flattening may be an important component in determining cell density and hence organ size.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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