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  • Evolution  (297)
  • Animals
  • EARTH RESOURCES AND REMOTE SENSING
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  • 101
    ISSN: 1573-5133
    Keywords: Phylogeny ; Madagascan endemic ; Egg structure ; Behaviour ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis The parental behaviour of the Madagascan cichlid,Paratilapia polleni, was studied in the laboratory. According to current hypotheses of phylogenetic intrarelationship for the family Cichlidae,Paratilapia is a representative of a phylogenetically primitive cichlid lineage, and as such is of particular interest in comparative evolutionary studies. Given the basal phylogenetic placement ofParatilapia it seems reasonable to expect that, if maternal participation in brood care arose within the extant Cichlidae, then the proposed plesiomorphic system of extensive male care of eggs and embryos may be retained in this taxon. This is not the case, and already by the fertilized-egg interval male and female roles inParatilapia are strongly differentiated with the female as the primary care giver. In addition to specialized behavioural roles, a unique egg morphology and mobile egg mass is described forParatilapia. The results of the study are discussed in the context of theories of the evolution of maternal brood care within the Cichlidae.
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  • 102
    ISSN: 1573-6857
    Keywords: Evolution ; lizards ; mitochondrial DNA ; parthenogenesis ; hybridization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Restriction enzymes were used to assay variation among mitochondrial DNAs from parthenogenetic and sexual species of Lacerta. This permitted identification of the sexual species that acted as the maternal parent of the various hybrid-parthenogenetic lineages. Lacerta mixta was the maternal parent for both L. dahli and L. armeniaca, L. valentini was the maternal parent for L. uzzelli, and L. raddei was the maternal parent of L. rostombekovi. The maternal ancestry of L. unisexualis is not as clear. The sample of L. nairensis was very similar to one from a population of L. raddei and either species could be the maternal parent of L. unisexualis. The parthenogenetic species all had very low nucleotide diversity in absolute terms and in comparison to their sexual relatives. The close similarity between mtDNAs from the parthenogenetic species and their respective sexual maternal ancestor species provides strong evidence for the recent origin of the parthenogens. The low diversity of the parthenogens indicates that few females were involved in their origins; the maternal parents of L. dahli and L. armeniaca could have come from a single population. The patterns of mtDNA variation in Lacerta are very similar to those in Cnemidophorus and Heteronotia, establishing recent and geographically restricted origins as a general feature of parthenogenetic lizards.
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  • 103
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    Genetica 86 (1992), S. 269-274 
    ISSN: 1573-6857
    Keywords: Evolution ; Introns ; Selfish DNA ; Sex ; transposons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract This paper summarizes some recent theories about the evolution of transposable genetic elements in outbreeding, sexual eukaryotic organisms. The evolutionary possibilities available to self-replicating transposable elements are shown to vary depending on the reproductive biology of the host genome. This effect can be used to explain, in part, the differences in abundance of transposable elements between prokaryotes and eukaryotes. It is argued that the pattern of sexual outbreeding seen in mammals and plants is especially favorable to the spread of transposons. Moreover, because transposon spread is facilitated by zygote formation, the evolutionary origin of sexual conjugation may have been due to selection on transposon-encoded genes. Finally, evidence is also presented that introns could have originated as transposable genetic elements.
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  • 104
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    Journal of statistical physics 69 (1992), S. 1137-1149 
    ISSN: 1572-9613
    Keywords: Evolution ; neural networks ; self-organizing criticality
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Although acquired characteristics are not incorporated into the genotype, some works have pointed to the influence of learning in evolution. We present a dynamic model of neural networks presenting evolutive features, even without modification in genotype, due to the introduction of culture. Our model presents other features that seem to reproduce some aspects of real world populations.
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  • 105
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    Environmental biology of fishes 33 (1992), S. 167-180 
    ISSN: 1573-5133
    Keywords: Gobio spp. ; Gobio albipinnatus ; Vimba vimba ; Blicca bjoerkna ; Hybrid ; Backcross ; Spawning grounds ; Allochrony ; Sympatric speciation ; Altricial ; Precocial ; Alprehost ; Epigenesis ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis When a new species is found, or a known one collected outside its recognized distribution, most people either assume that the species has been overlooked in the past or that it has recently invaded the area in question from elsewhere. While other, more evolutionary explanations are possible, these are nearly always ignored, in spite of the common perception that animals are constantly in states of change. Recent findings in the Danube River are used as examples for such alternative interpretations. The case of two forms of Vimba — short and long snouted — which live in sympatry in the upper Danube is dispelled, as one of them is identified as a hybrid between female V. vimba and male Blicca bjoerkna. Frequent occurrences of this hybrid (and a few of its backcrosses) in recent times are explained by man-induced alteration of reproductive isolation between their parent species, caused by the impoundment of the river by dams built as part of the Rhein-Main-Donau Kanal. These impoundments, however, might be responsible not only for the creation of hybrids but also for direct speciation, as the case of Gobio albipinnatus may represent. The ability for epigenetic creation of two alternative life-history states (as part of the theory of alprehost) and the survival of an alternative state when environmental conditions change might be ultimately responsible for the appearance of a new taxon.
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  • 106
    ISSN: 1432-136X
    Keywords: Hemocyanin ; Arylphorin ; Larval serum proteins ; Evolution ; Arthropods
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Arylphorin was purified from larvae of the blowfly Calliphora vicina and studied in its oligomeric form and after dissociation at pH 9.6 into native subunits. In accordance with earlier literature, it was electrophoretically shown to be a 500 kDa hexamer (1×6) consisting of 78 kDa polypeptides (= subunits). Electron micrographs of negatively stained hexamers show a characteristic curvilinear, equilateral triangle of 12 nm in diameter (top view) and a rectangle measuring 10×12 nm (side view). Alternatively, particles in the top view orientation exhibit a roughly circular shape 12 nm in diameter. Crossed immunoelectrophoresis revealed the presence of a major subunit type; the nature of a very minor and a third immunologically separated component remains unclear. A novel 2×6 arylphorin particle was detected and isolated. It comprises less than 10% of the total arylphorin material and shows a long, narrow interhexamer bridge in the electron microscope. An arylphorin dissociation intermediate identified as a trimer (1/2×6) was isolated; its possible quaternary structure is discussed on the basis of electron micrographs. The epitope of monoclonal antibody Ec-7 directed against tarantula (Eurypelma californicum) hemocyanin subunit d and also reactive to Calliphora arylphorin was traced to a highly conserved peptide of 27 amino acids localized in the center of the protein. The primary structure of Calliphora arylphorin as published in our preceding paper (Naumann and Scheller 1991) is compared in detail to the sequences of spider and spiny lobster hemocyanin. This revealed a basic framework of 103 strictly conserved amino acids. Isofunctional exchanges are proposed for another 76 positions. On the basis of these similarities, and the published three-dimensional model of spiny lobster hemocyanin, a detailed model of the quaternary structure of Calliphora arylphorin is presented. A second larval storage protein previously termed protein II was purified from Calliphora hemolymph. It was demonstrated to be a 500 kDa hexamer of 83 kDa subunits. In the electron microscope it shows a cubic view 9 nm in length with a large central hole and a rectangular view (9×10 nm) with a large central cavity. A morphologically very similar hemolymph protein was detected in Drosophila melanogaster larvae. From its structural appearance it is uncertain whether protein II belongs to the hemocyanin superfamily or not.
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  • 107
    ISSN: 1824-310X
    Keywords: Prosimians ; Hapalemur ; Highly repeated DNA ; Evolution ; Restriction enzymes ; Hybridization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract This study confirms, on the basis of our molecular biology results and in accordance with cytogenetic, morphological and ethological data, the specific status ofHapalemur aureus. Furthermore, it appears clearly thatHapalemr simus began its differentiation fromHapalemur griseus griseus andHapalemur aureus (wich have a common branch) shortly after the separation ofLemur catta from the phylogenetic tree of theL. catta/ Hapalemur group.
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  • 108
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    Journal of molecular evolution 33 (1991), S. 68-75 
    ISSN: 1432-1432
    Keywords: DNA ; Genome size ; Repetitive DNA ; Amphibians ; Reptiles ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Many characters differentiate amphibian from reptilian genomes. The former have, on the average, larger and more variable genome sizes, a greater repetitive DNA percentage, and a higher interspersion level among DNAs with different degrees of repetitivity. Reptiles have more reduced and uniform genome sizes, a repetitive DNA percentage generally lower than 50%, and a lower interspersion level. Other differences can be observed in the chromosome banding and in the correlations between genome size and other morphometric and functional parameters of the cell. The differences found in amphibians and reptiles seem to indicate that in these two vertebrate classes there is a different tendency toward or tolerance of the accumulation and preservation of genetically dispensable DNA fractions. This might depend either on a different propensity toward genic amplification or on the appearance, in reptiles, of stricter and more efficient constraints regulating genome size.
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  • 109
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    Journal of molecular evolution 33 (1991), S. 133-141 
    ISSN: 1432-1432
    Keywords: Y-chromosome ; DNA ; Human ; Primate ; Evolution ; PUPPY sequence ; Alu element
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A Y-chromosomal DNA fragment has been isolated from a human Y-Charon 21A recombinant library. Evolutionary analysis of 1F5 indicates that the size and sequence of this fragment have been conserved in higher primates. Deletion mapping and in situ hybridization analysis have localized 1F5 to the middle euchromatic portion of the long arm of the human Y chromosome at Yq11.2. Sequence analysis revealed the presence of an atypical Alu element and two regions rich in polypyrimidine-polypurine residues.
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  • 110
    ISSN: 1432-1432
    Keywords: Bacteria ; Sugars ; Phosphotransferase system ; Transport proteins ; Evolution ; Sequence comparisons ; NADH dehydrogenase ; Mitochondria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The amino acid sequences of 15 sugar permeases of the bacterial phosphoenolpyruvatedependent phosphotransferase system (PTS) were divided into four homologous segments, and these segments were analyzed to give phylogenetic trees. The permease segments fell into four clusters: the lactose-cellobiose cluster, the fructose-mannitol cluster, the glucose-N-acetylglucosamine cluster, and the sucrose-β-glucoside cluster. Sequences of the glucitol and mannose permeases (clusters 5 and 6, respectively) were too dissimilar to establish homology with the other permeases, but short regions of statistically significant sequence similarities were noted. The functional and structural relationships of these permease segments are discussed. Some of the homologous PTS permeases were found to exhibit sufficient sequence similarity to subunits 4 and 5 of the eukaryotic mitochondrial NADH dehydrogenase complex to suggest homology. Moreover, subunits 4 and 5 of this complex appeared to be homologous to each other, suggesting that these PTS and mitochondrial proteins comprise a superfamily. The integral membrane subunits of the evolutionarily divergent mannose PTS permease, the P and M subunits, exhibited limited sequence similarity to subunit 6 of the mitochondrial F1F0-ATPase and subunit 5b of cytochrome oxidase, respectively. These results suggest that PTS sugar permeases and mitochondrial proton-translocating proteins may be related, although the possibility of convergent evolution cannot be ruled out.
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  • 111
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    Journal of molecular evolution 32 (1991), S. 296-303 
    ISSN: 1432-1432
    Keywords: Prebiotic chemistry ; Primordial soup ; Oparin hypothesis ; Evolution ; Impact catastrophism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In the traditional concept for the origin of life as proposed by Oparin and Haldane in the 1920s, prebiotic reactants became slowly concentrated in the primordial oceans and life evolved slowly from a series of highly protracted chemical reactions during the first billion years of Earth's history. However, chemical evolution may not have occurred continuously because planetesimals and asterioids impacted the Earth many times during the first billion years, may have sterilized the Earth, and required the process to start over. A rapid process of chemical evolution may have been required in order that life appeared at or before 3.5 billion years ago. Thus, a setting favoring rapid chemical evolution may be required. A chemical evolution hypothesis set forth by Woese in 1979 accomplished prebiotic reactions rapidly in droplets in giant atmospheric reflux columns. However, in 1985 Scherer raised a number of objections to Woese's hypothesis and concluded that it was not valid. We propose a mechanism for prebiotic chemistry in clouds that satisfies Scherer's concerns regarding the Woese hypothesis and includes advantageous droplet chemistry. Prebiotic reactants were supplied to the atmosphere by comets, meteorites, and interplanetary dust or synthesized in the atmosphere from simple compounds using energy sources such as ultraviolet light, corona discharge, or lightning. These prebiotic monomers would have first encountered moisture in cloud drops and precipitation. We propose that rapid prebiotic chemical evolution was facilitated on the primordial Earth by cycles of condensation and evaporation of cloud drops containing clay condensation nuclei and nonvolatile monomers. For example, amino acids supplied by, or synthesized during entry of, meteorites, comets, and interplanetary dust would have been scavenged by cloud drops containing clay condensation nuclei. Polymerization would have occurred within cloud systems during cycles of condensation, freezing, melting, and evaporation of cloud drops. We suggest that polymerization reactions occurred in the atmosphere as in the Woese hypothesis, but life originated in the ocean as in the Oparin-Haldane hypothesis. The rapidity with which chemical evolution could have occurred within clouds accommodates the time constraints suggested by recent astrophysical theories.
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  • 112
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    Journal of molecular evolution 32 (1991), S. 415-420 
    ISSN: 1432-1432
    Keywords: Drosophila melanogaster ; Drosophila virilis ; mastermind ; Gene comparison ; Repetitive sequences ; Homopolymers ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Themastermind gene ofDrosophila melanogaster encodes a novel, highly repetitive nuclear protein required for neural development. To identify functionally important regions we have initiated an interspecific comparison of the gene inDrosophila virilis. Mastermind transcription and genomic organization are similar in both species and sequence analysis reveals significant conservation in a major cluster of charged amino acids. In contrast, extensive variation is noted in homopolymer domains that immediately flank the acidic cluster. Distinct patterns of evolutionary change can be identified: the major difference between unique regions are occasional amino acid substitutions whereas the repetitive areas are characterized by numerous large in-frame insertions/deletions and a nearly threefold higher rate of amino acid replacement. Conservation of the acidic domain suggests that it has an important functional role whereas the hypervariable homopolymer regions appear to be under less selective constraints than adjacent unique areas.
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  • 113
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    Journal of molecular evolution 32 (1991), S. 24-30 
    ISSN: 1432-1432
    Keywords: Short sequence distribution ; Sequence constraints ; Averaged sequence ; Sequence structure ; Asymmetric nucleotide sequences ; GC content ; Evolution ; Evolutionary constraints
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The data from a genomic library can be sorted into the frequencies of every possible tetranucleotide in the sequence. This tabulation, a short sequence distribution, contains the frequency of occurrence of the 256 tetranucleotides and thus seems to serve as a vehicle for averaging sequence information. Two such distributions can be readily compared by correlation. Reported here are correlations (Spearmanr s) of the distributions from all of the genomic libraries in GenBank 44.0 with sizes equal to or larger than that ofSalmonella typhimurium, except for the data for mouse and humans. All of the organisms examined showed highly significant correlations between the two DNA strands (not the complementarity expected from base pairing). Of 155 comparisons between libraries, 132 showed significant correlations at the 99% confidence level. Application of the correlation coefficients as a similarity matrix clustered most organisms in a phenogram in a pattern consistent with other hypotheses. This suggests a highly conserved pattern underlying all other genetic information in cellular DNA and affecting both DNA strands, perhaps caused by interaction with conserved factors necessary for DNA packaging.
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  • 114
    ISSN: 1432-1432
    Keywords: Lagomorphs ; Rabbit ; Mitochondrial DNA ; Heteroplasmy ; Restriction site polymorphism ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A characterization was conducted on mitochondrial DNA (mtDNA) molecules extracted separately from 107 European rabbits (Oryctolagus cuniculus) both wild and domestic, 13 European hares (Lepus capensis), and 1 eastern cottontail (Sylvilagus floridanus). Experimentally this study took into account restriction site polymorphism, overall length variation of the noncoding region, and numbers of repeated sequences. Nucleotide divergences indicate that the mtDNAs from the three species derived from a common ancestor some 6–8 million years (Myr) ago. Every animal appeared heteroplasmic for a set of molecules with various lengths of the noncoding region and variable numbers of repeated sequences that contribute to them. This systematic heteroplasmy, most probably generated by a rate of localized mtDNA rearrangements high enough to counterbalance the cellular segregation of rearranged molecules, is a shared derived character of leporids. The geographic distribution of mtDNA polymorphism among wild rabbit populations over the western European basin shows that two molecular lineages are represented, one in southern Spain, the second over northern Spain, France, and Tunisia. These two lineages derived from a common ancestor some 2 Myr ago. Their present geographical distribution may be correlated to the separation of rabbits into two stocks at the time of Mindel glaciation. Finally the distribution of mtDNA diversity exhibits a mosaic pattern both at inter- and intrapopulation levels.
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  • 115
    ISSN: 1432-1432
    Keywords: Aspergillus ; 5S rRNA genes ; 5S rRNA pseudogenes ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have cloned and determined the nucleotide sequence of 18 DNA fragments hybridizing to 5S rRNA from twoAspergillus species-A. wentii andA. awamori. Four of the analyzed sequences were pseudogenes. The gene sequences of these two species were very similar and differed fromAspergillus nidulans at both constant and microheterogeneous sites.
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  • 116
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    Journal of molecular evolution 33 (1991), S. 464-469 
    ISSN: 1432-1432
    Keywords: Evolution ; tRNA ; Ribosome ; Peptide bond ; Catalytic RNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Continuation of early evolutionary bonding between tRNAs would provide a solution to residence time problems between peptidyl-tRNA and mRNA. It could also improve the speed of peptide bond formation by holding the amino acid close to the growing peptide. The tRNA clover leaf structure would allow each tRNA to from a TΨC(GA)-loop bond to one side and a D-loop bond to the other, hence fixing itself within a group of tRNAs, all attached to the mRNA. This can be developed into a system for peptide elongation in which bonds are made and broken in an ordered sequence, with each step triggering the next. This leads to a model system that fits with some recent propsals for a three-site ribosome.
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  • 117
    ISSN: 1432-1432
    Keywords: Retroposon ; Salmonid ; +RNA ; Evolution ; Average sequence divergence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary An in vitro runoff transcription assay of total genomic DNA was developed. As an example of use of this assay, analysis of a highly repetitive sequence in the cherry salmon (Oncorhynchus masou) is described. Total genomic DNA of the cherry salmon was completely digested with Hpa 1, whose site is known to be in the tRNA-unrelated region of the cherry salmon Hpa 1 family. On transcription of the digested DNA in a HeLa cell extract, a discrete-sized RNA of about 100 nucleotides, constituting 70% of the transcripts, was produced, whereas on transcription of the undigested total DNA, only smeared RNA was obtained. In a fingerprint, the oligonucleotides of the discrete transcript from the digested total DNA were very distinct and exactly corresponded to those of a transcript from an Hpa 1 digest of a cloned DNA, but with few extra oligonucleotides. These results showed that the cherry salmon Hpa 1 family constitutes a major repetitive family in the genome of the cherry salmon. For determination of the distribution of the salmonid Hpa 1 family in other salmonid species, the same analysis was applied to DNAs from the chum salmon (Oncorhynchus keta), brown trout (Salmo trutta), Japanese common charr (Salvelinus leucomaenis pluvius), and Japanese huchen (Hucho perryi). The results showed that the salmonid Hpa 1 family is widespread in the genomes of salmonid species. A method and equations are also presented for estimating the relationship between the ratio of a given repetitive family to all the Pol III genes and its average sequence divergence by calculating the molar ratio of the runoff transcript to all the in vitro Pol III transcripts.
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  • 118
    ISSN: 1432-1432
    Keywords: Phylogenetic tree ; Likelihood method ; RNA polymerase ; Archaebacteria ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The amino acid sequences of the largest subunits of the RNA polymerases I, II, and III from eukaryotes were compared with those of archaebacterial and eubacterial homologs, and their evolutionary relationships were analyzed in detail by a recently developed tree-making method, the likelihood method of protein phylogeny, as well as by the neighbor-joining method and the parsimony method, together with bootstrap analyses. It was shown that the best tree topologies predicted by the first two methods are identical, whereas the last one predicts a distinct tree. The maximum likelihood tree revealed that, after the separation from archaebacteria, the three eukaryotic RNA polymerases diverged from an ancestral precursor in the eukaryotic lineage. This result is contrasted with the published result showing multiple origins for the three eukaryotic polymerases. It was shown that eukaryotic RNA polymerase I evolved much more rapidly than RNA polymerases II and III: The N-terminal half of RNA polymerase I shows an extraordinarily high evolutionary rate, possibly due to relaxed functional constraints. In contrast the evolutionary rate of archaebacterial RNA polymerase is remarkably limited. In addition, including the second largest subunit of the RNA polymerase, a detailed analysis for the branching pattern of the three major groups of archaebacteria was carried out by the maximum likelihood method. It was shown that the three major groups of archaebacteria are likely to form a single cluster; that is, archaebacteria are likely to be monophyletic as originally proposed by Woese and his colleagues.
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  • 119
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    Journal of molecular evolution 33 (1991), S. 42-48 
    ISSN: 1432-1432
    Keywords: Satellite DNA ; Mouse ; Human chromosomes 13 and 21 ; Evolution ; Saltatory amplification ; Homogenization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The hypothesis that highly reiterated satellite DNAs in present-day populations evolve by molecular mechanisms that create, by saltatory amplification steps, new long arrays of satellite DNA, and that such long arrays are used for homogenization purposes, has been tested both in mouse and in humans. In mouse, the data obtained are consistent with this hypothesis. This was tested in more detail on chromosomes 13 and 21 of the human genome. A Centre d'Etudes du Polymorphisme Humain family, which in some individuals exhibits strong supplementary DNA bands following TaqI restriction endonuclease digestion and conventional gel electrophoresis, was analyzed by pulse field gel electrophoresis following restriction by BamHI. The supplementary bands on chromosome 13 (18 times the basic alpha satellite DNA repeat) and on chromosome 21 (a 9.5-mer) segregated with centromeric alpha satellite DNA blocks of 5 and 5.3 megabases, respectively. These are by far the largest alpha satellite block lengths seen in all chromosome 13 and chromosome 21 centrometric sequences so far analyzed in this manner. The possibility that these supplementary alpha satellite sequences were created in single individuals by saltatory amplification steps is discussed in light of our own data and that published by others. It is proposed that deletion events and unequal cross-overs, which both occur in large satellite DNA arrays, contribute to the homogenization of size and sequence of the alpha satellite DNA on most chromosomes of humans.
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  • 120
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    Journal of molecular evolution 33 (1991), S. 207-208 
    ISSN: 1432-1432
    Keywords: Evolution ; Vesicle ; Biogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The earliest fossil stromatolites present evidence of a complex ecosystem of photosynthetic organisms. Because the origin of present life can be dated within a few hundred million years prior to these fossils, their complexity poses a problem. A heuristic model outlines the first radiation leading to the universal ancestor.
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  • 121
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    International journal of biometeorology 35 (1991), S. 180-186 
    ISSN: 1432-1254
    Keywords: Evolution ; Paleophysiology ; Primates ; Sweating ; Thermoregulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Notes: Abstract Mammals have two kinds of sweat glands, apocrine and eccrine, which provide for thermal cooling. In this paper we describe the distribution and characteristics of these glands in selected mammals, especially primates, and reject the suggested development of the eccrine gland from the apocrine gland during the Tertiary geological period. The evidence strongly suggests that the two glands, depending on the presence or absence of fur, have equal and similar functions among mammals; apocrine glands are not primitive. However, there is a unique and remarkable thermal eccrine system in humans; we suggest that this system evolved in concert with bipedalism and a smooth hairless skin.
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  • 122
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    Current genetics 20 (1991), S. 173-175 
    ISSN: 1432-0983
    Keywords: Batophora ; Small subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (SSU) ; rbcS cDNA sequence ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Two cDNA clones for the small subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (SSU) of Batophora oerstedii were isolated and sequenced. One clone contains the coding information for the complete SSU precursor protein. As in two other species of Dasycladaceae (Acetabularia mediterranea and A. cliftonii), the rbcS cDNA sequences of B. oerstedii display the codons TAA or TAG, which seem to code for glutamine, in the reading frame. The amino acid substitution rate for the SSU protein was calculated to be 0.35–0.41 amino acids per 109 years per site based on the substitutions observed in the SSU amino acid sequences of Acetabularia and Batophora.
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  • 123
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    Journal of comparative physiology 169 (1991), S. 191-200 
    ISSN: 1432-1351
    Keywords: Insect ; Behaviour ; Pattern generation ; Grasshopper ; Stridulation ; Bilateral coordination ; Abdominal ganglia ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Stridulation of grasshoppers is controlled by hemisegmental pattern generator subunits which probably are restricted to the metathoracic ganglion complex (TG3-complex). The coordination of left and right pattern generator subunits depends on commissures of the TG3-complex (Ronacher 1989). The coordination of the stridulatory movements was studied in Chorthippus dorsatus males with partial mediosagittal incisions in the TG3-complex. Animals bearing anterior incisions in the TG3-complex, by which all commissures of the metathoracic neuromere and the first abdominal neuromere were transected, were still able to produce bilaterally coordinated species-specific stridulatory movements. Commissures of the T3- and A1-neuromere, thus, are not necessary, and the A2-, A3-commissures are sufficient for this coordination (Figs. 3, 4). Animals with partial posterior incisions, extending until A1, had deficits in their stridulation pattern; the coordination between the hindlegs was impaired though not completely lost (Fig. 6). This is discussed in view of the structure of ‘stridulation interneurons’ identified in a related grasshopper species (Omocestus viridulus). These results indicate an unexpected substantial contribution of the abdominal neuromeres A2 and A3 to the control of stridulatory movements. This constitutes an interesting parallel to the flight control system of locusts where interneurons located in the first 3 abdominal neuromeres also appear to contribute to the flight pattern generator (Robertson et al. 1982).
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  • 124
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    Journal of mathematical biology 29 (1991), S. 743-761 
    ISSN: 1432-1416
    Keywords: Transposable element ; Branching-processes ; Population genetics ; Evolution ; Mobile genetic elements
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Abstract We have formulated a very general mathematical model to analyze the evolution of transposable genetic elements in prokaryotic populations. Transposable genetic elements are DNA sequences able to replicate and insert copies of themselves at new locations in the genome. This work characterizes the equilibrium distribution of copy number under the influence of copy number-dependent selection, transposition and deletion. Our principal results concern the equilibrium distribution of copy number in response to various selective regimes. For particular transposition patterns (e.g. unregulated transposition or copy number-dependent transposition), equilibrium distributions are calculated numerically for a variety of specific selection patterns. Selection is quantified through specification of the expected number of offspring for individuals of each type, which is generally a non-increasing function of copy number, in accord with the usual evolutionary speculations.
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    Journal of comparative physiology 168 (1991), S. 461-467 
    ISSN: 1432-1351
    Keywords: Electric fish ; Sternopygus ; Jamming avoidance ; Electrolocation conditioning ; Preadaptation ; Temporal filtering ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Several species of weakly electric fish reflexively change their frequency of electric organ discharge (EOD) in response to sensing signals of similar frequency from conspecifics; that is, they exhibit jamming avoidance responses (JAR).Eigenmannia increases its EOD frequency if jammed by a signal of lower frequency and decreases its EOD frequency if jammed by a signal of higher frequency. This discrimination is based on an analysis of the patterns of amplitude modulations and phase differences resulting from signal interference. Fish of the closely related genus,Sternopygus, however, do not exhibit a JAR. Here we show that despite lacking this behavior,Sternopygus shares many sensory processing capacities withEigenmannia: 1. Fish could be conditioned to discriminate the sign of the frequency difference (Df) between an exogenous sinusoidal signal and its own EODs with as few as 300 training trials. 2. Fish can discriminate the sign of Df for jamming signals with an amplitude as low as 2 μV/cm (p-p); which is approximately 40 dB below the amplitude of the fish's EOD, as measured lateral to the operculum. 3. Fish appear to discriminate the sign of Df by evaluating modulations in signal amplitude and differences in the timing of signals received by different areas of the body surface. 4. Sternopygus processes electrosensory information through band-pass modulation filters. Tuning to modulation rates over at least 4–16 Hz exists.
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    Theoretical and applied genetics 81 (1991), S. 13-20 
    ISSN: 1432-2242
    Keywords: Potato ; Chloroplast DNA ; Sequence comparison ; Nucleotide substitution rate ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A deletion specific to chloroplast (ct) DNA of potato (Solanum tuberosum ssp. tuberosum) was determined by comparative sequence analysis. The deletion was 241 bp in size, and was not flanked by direct repeats. Five small, open reading frames were found in the corresponding regions of ctDNAs from wild potato (S. tuberosum ssp. andigena) and tomato (Lycopersicon esculentum). Comparison of the sequences of 1.35-kbp HaeIII ctDNA fragments from potato, tomato, and tobacco (Nicotiana tabacum) revealed the following: the locations of the 5′ ends of both rubisco large subunit (rbcL) and ATPase beta subunit (atpβ) mRNAs were probably the same as those of spinach (Spinacia oleracea); the promoter regions of the two genes were highly conserved among the four species; and the 5′ untranslated regions diverged at high rates. A phylogenetic tree for the three potato cultivars, one tomato cultivar, and one tobacco cultivar has been constructed by the maximum parsimony method from DNA sequence data, demonstrating that the rate of nucleotide substitution in potato ctDNA is much slower than that in tomato ctDNA. This fact might be due to the differences in the method of propagation between the two crops.
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    Theoretical and applied genetics 82 (1991), S. 57-64 
    ISSN: 1432-2242
    Keywords: Cultivated rice ; Wild rice ; RFLP ; Satellite DNA ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A 352-bp EcoRI fragment from rice DNA was cloned and shown to be a member of a tandem repeat. Sequence determination revealed homologies with human alpha satellite DNA and maize knob heterochromatin specific repeat. This 352-bp sequence is highly specific for the AA genome of rice. However, copy number and sequence organization are variable, depending on the accession analyzed. Several examples of amplification were observed in O. rufipogon and O. longistaminata. Use of resolutive polyacrylamide gel electrophoresis and 4-bp cutter enzymes allowed one to distinguish between the Indica and Japonica subtypes of O. sativa. The same method also discriminates between two groups of O. rufipogon, the presumed ancestor of O. sativa, suggesting that the present day Indica and Japonica subtypes originated independently from two O. rufipogon distinct populations.
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  • 128
    ISSN: 1615-6102
    Keywords: Cell division cycle ; Wheat ; cdc2 ; suc1 ; Protein kinase ; H1 histone kinase ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Thecdc2-like p34 protein of wheat is closely similar to the p34cdc2 enzyme of yeasts and animals since both have binding affinity for p13suc1 protein encoded by the fission yeastsuc1 gene. In yeast p13suc1 participates in modulation of p34cdc2 activity and is necessary for completion of mitosis. Wheat p34 that was affinity purified on p13suc1 contained the PSTAIR amino acid sequence that is present in all known p34cdc2 homologues and it also had H1 histone protein kinase activity that was independent of calcium and cyclic AMP, which is characteristic of p34cdc2 in vitro. Functional equivalence with the known cell cycle control protein supports our earlier proposition that the high level of this homologue in wheat leaf meristem is important in determining where cell division can occur and the capacity for resumption of cell division. The affinity of plant p34 for fission yeast p13suc1 suggested that a similar association occurs in plants. We have detected a plant homologue of pl3suc1 using affinity-purified antibody raised against the fission yeast protein, in wheat, pea andChlamydomonas. We conclude that the distribution of p13suc1 homologue in plants is likely to be ubiquitous. Thesuc1 gene function inSchizosaccharomyces pombe is essential for mitosis, in which it is required for inactivation of p34cdc2. We propose that association of plant p34 with p13suc1 is similarly involved in plant mitosis.
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  • 129
    ISSN: 1615-6102
    Keywords: Green algae ; Flagellar beat ; Video analysis ; Evolution ; Swimming patterns ; Prasinophyceae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The flagellar beat and swimming patterns of flagellated cells of 22 green plants, including 17 green flagellates (volvocalean and prasinophyte algae), motile cells of three seaweeds,Bryopsis, Caulerpa, andUlva, sperms of a liverwort,Marchantia, and a fern,Athyrium, were examined using a high-speed video system. So-called breast-stroke is widely distributed in green plants, and occurs rarely in prasinophyte flagellates and ulvophycean algae; in these algal groups flagellar beat similar to that found in animal sperm is common, both during forward and backward swimming. Different types of swimming patterns were observed in prasinophytes. The results indicate evolutionary trends of flagellar beat and swimming patterns in green plants such as change from backward to forward swimming, from flagellar to ciliary beating and from uni-directional (parallel) to radial-directional (cruciate) beating. Such trends are shown in two prasinophyte groups, thePyramimonas-lineage andTetraselmis-lineage.
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    Biology and philosophy 6 (1991), S. 59-80 
    ISSN: 1572-8404
    Keywords: Evolution ; semantic approach ; theory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Philosophy
    Notes: Abstract Paul Thompson, John Beatty, and Elisabeth Lloyd argue that attempts to resolve certain conceptual issues within evolutionary biology have failed because of a general adherence to the received view of scientific theories. They maintain that such issues can be clarified and resolved when one adopts a semantic approach to theories. In this paper, I argue that such conceptual issues are just as problematic on a semantic approach. Such issues arise from the complexity involved in providing formal accounts of theoretical laws and scientific explanations. That complexity is due to empirical and pragmatic considerations, not one's adherence to a particular formal approach to theories. This analysis raises a broader question. How can any formal account properly represent the complex nature of empirical phenomena?
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    Biology and philosophy 6 (1991), S. 81-92 
    ISSN: 1572-8404
    Keywords: Evolution ; fitness ; natural selection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Philosophy
    Notes: Abstract This paper considers a variety of attempts to define fitness in such a way as to defend the theory of evolution by natural selection from the criticism that it is a circular argument. Each of the definitions is shown to be inconsistent with the others. The paper argues that the environment in which an animal evolves can be defined only with respect to the properties of the phenotype of the animal and that it is therefore not illuminating to try to explain the phenotypic properties of the animal in terms of adaptation to an environment that is defined by those very properties. Furthermore, since there is no way that the environment can be defined independently of the presence of the animal there is no way that the quality of an animal can be assessed; and there can be no objective criteria by whichany form of selection can be carried out, therefore there can be no criteria by whichnatural selection can be carried out. It is proposed that fitness is nothing more than the production of offspring, that this is a phenotypic property like all the others, and if it is heritable then the offspring of the parents that produce the most offspring will themselves produce the most offspring, and that in principle it is impossible to account for this in terms of the other phenotypic properties of the fittest animals except by circular argument. Differential rates of reproduction are the causes of evolution and the phenotypic causes are strictly inexplicable.
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  • 132
    ISSN: 1615-6110
    Keywords: Angiosperms ; Leguminosae ; Medicago truncatula f.laxicycla ; M. laxispira ; Evolution ; adaptation ; seed germination ; chromosome number ; Flora of Libya
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Medicago truncatula is a member ofMedicago sect.Spirocarpos, in which all 34 species have coiled fruit, usually tightly coiled, that permanently retain the seeds. A variant ofM. truncatula from Libya is unique for the species in possessing very loosely coiled fruits, and is here recognized as a new forma,M. truncatula f.laxicycla E. Small. In germination tests of a number of species ofMedicago, the unusual Libyan variant proved to be the only one in which rapid and simultaneous germination of most of the seeds occurred while still within a fruit. The loose coiling of the fruit of the Libyan variety appears to facilitate water entry and seedling escape. Its rapid germination might adapt it to respond quickly to intermittently available moisture, but at the cost of abandoning the strategy of intermittent germination adopted by other populations ofMedicago sect.Spirocarpos.
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    Molecular genetics and genomics 228 (1991), S. 324-327 
    ISSN: 1617-4623
    Keywords: Yolk proteins ; Gene families ; Evolution ; Egg production ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The yolk proteins of Drosophila melanogaster comprise a family of three related yolk polypeptides each encoded by a single-copy gene. We show by genetic crosses that each gene makes an equivalent contribution to the fecundity and fertility of the female and they do not individually provide unique functions to the embryo. We show that the number of eggs laid by a female depends upon the number of genes encoding yolk polypeptides present in the genome and furthermore that the probability of an egg hatching into an adult also critically depends upon the number of yolk protein genes present in the mother. This suggests that the three yolk protein-encoding genes in Drosophila melanogaster may have arisen by duplication, then been maintained for quantitative reasons because they increased egg production and fertility, rather than each protein evolving a different function as is the case with most small gene families, such as tubulins and collagen genes.
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    Molecular genetics and genomics 231 (1991), S. 53-58 
    ISSN: 1617-4623
    Keywords: Chlamydomonas moewusii ; Mitochondrial DNA ; Map ; Gene localization ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We report that the mitochondrial genome of Chlamydomonas moewusii has a 22 kb circular map and thus contrasts with the mitochondrial genome of Chlamydomonas reinhardtii, which is linear and about 6 kb shorter. Overlapping restriction fragments spanning over 90% of the C. moewusii mitochondrial DNA (mtDNA) were identified in a clone bank constructed using a Sau3AI partial digest of a C. moewusii DNA fraction enriched for mtDNA by preparative CsCI density gradient centrifugation. Overlapping Sau3AI clones were identified by a chromosome walk initiated with a clone of C. moewusii mtDNA. The mtDNA map was completed by Southern blot analysis of the C. moewusii mtDNA fraction using isolated mtDNA clones. Regions that hybridized to C. reinhardtii or wheat mitochondrial gene probes for subunit I of cytochrome oxidase (cox1), apocytochrome b (cob), three subunits of NADH dehydrogenase (nadl, nad2 and nad5) and the small and the large ribosomal RNAs (rrnS and rrnL, respectively) were localized on the C. moewusii mtDNA map by Southern blot analysis. The results show that the order of genes in the mitochondrial genome of C. moewusii is completely rearranged relative to that of C. reinhardtii.
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    Molecular genetics and genomics 231 (1991), S. 106-112 
    ISSN: 1617-4623
    Keywords: Serine tDNAs ; Glutamine tDNA ; Bovine consensus sequence ; Short interspersed nuclear element ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A bovine tRNA gene cluster has been characterized and the sequences of four tDNAs determined. Two of the tDNAs could encode tRNASer IGA, one tDNASer UGA, and the fourth tRNAGln CUG. The three serine tDNAs representing the UCN codon isoacceptor family are almost identical. However, the sequence of the tDNASer TGA differs from a previously sequenced bovine tDNASer TGA at 12 positions (ca. 14%). This finding suggests that in the bovine genome, two subfamilies of genes might encode tRNASer UGA. It also raises the possibility that new genes for a specific UCN isoacceptor might arise from the genes of a different isoacceptor, and could explain previously observed differences between species in the anticodons of coevolving pairs of tRNAsSer UCN. The gene cluster also contains complete and partial copies, and fragments, of the BCS (bovine consensus sequence) SINE (short interspersed nuclear element) family, six examples of which were sequenced. Some of these elements occur in close proximity to two of the serine tDNAs.
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  • 136
    ISSN: 1617-4623
    Keywords: Archaebacteria ; Evolution ; Gene cluster ; Halobacterium marismortui ; Ribosomal protein genes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The nucleotide sequence has been determined of a 4700 by region from a ribosomal protein gene cluster of Halobacterium marismortui (Haloarcula marismortui), which is equivalent to part of the spectinomycin operon of Escherichia coli. The genes were localized on the recombinant λEMBL3 clone PP*7, which also contains several other ribosomal protein genes from the DNA region in H. marismortui equivalent to the linked S10/spc operon. The genes analysed encode ten ribosomal proteins, namely HmaL5, HmaS14, HmaS8, HmaL6, HL5, HL24, HmaL18, HmaS5, HmaL30 and HmaL15. The gene organization of the archaebacterial cluster is similar to that in eubacteria but has two additional genes, namely those encoding HL5 and HL24, which were identified as extra proteins that are apparently not present in E. coli. These correspond to the gene products of orfd and orfe in Methanococcus vannielii and also have eukaryotic counterparts.
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    Environmental biology of fishes 32 (1991), S. 193-198 
    ISSN: 1573-5133
    Keywords: Primitive fishes ; Comparative biochemistry ; Enzymology ; Evolution ; Crossopterygn ; Actinistia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis The coelacanth, Latimeria chalumnae, is often referred to as a living relic. The opportunity to examine its biochemical molecular structure was sought in an effort to define the degree of its genetic variability. The coelacanth is thought to live only in a small area around the Comoro Islands in the Western Indian Ocean. The scenario presented suggests that the coelacanth may have lost genetic variability as a result of genetic drift within a small population. The narrow geographic range of the coelacanth suggests adjustment to a relatively limited environment. The loss of specific alleles through genetic drift can reduce the ability of a fish population to adapt to changes in environmental conditions. The coelacanth needs strong conservation measures to be taken to curtail the capture of specimens and for the protection of its limited natural habitat.
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    AI & society 5 (1991), S. 246-254 
    ISSN: 1435-5655
    Keywords: Gradualness ; Computers ; Evolution ; Hypertext
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract In making a contribution, a person's life gains meaning. A small contribution affects a few people for a short time, while a large contribution affects many people for a long time. Within the framework of an abstract, computational world, a metric on contributions is defined. Simulation of the computational model shows the critical role of gradualness. Gradualness can be supported by human-computer systems in which the computer does the copying and arithmetic, and the human applies a rich understanding of the world. The role of gradualness in the research areas of machine learning and hypertext is highlighted.
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    Environmental biology of fishes 32 (1991), S. 23-58 
    ISSN: 1573-5133
    Keywords: Coelacanth ; Rates of morphological evolution ; Evolutionary morphology ; Cladistics ; Phylogeny ; Evolution ; Paleontology ; Tempo ; Bradytely ; Diversity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis The interrelationships of 31 actinistian species (including Latimeria chalumnae) are analyzed based on a cladistic analysis of 75 osteological characters. Inference of evolutionary trends (e.g., modification of body shape and skull morphology) from the phylogenetic patterns demonstrates that the morphology of actinistians is less conservative than has been proposed previously. This empirical cladistic approach supports two distinct tempos of evolution during an evolutionary history of 380 million years. Along a phylogenetic pathway originating with a Devonian stem-species and ending with the living Latimeria chalumnae (including 101 morphological changes and 18 cladogenetic events), the first tempo occurred during the Devonian — Permian periods as a decreasing rate of morphological changes, which was followed by a stabilizing tempo during the Permian — Recent periods. The decreasing tempo is characterized by a sequence of gradual versus quantum temporal changes and low versus faster rates, whereas the stabilizing tempo primarily is gradual and low. In contrast to a common assumption, no significant correlation was found between the rates of morphological evolution and the temporal diversity of species.
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    Environmental biology of fishes 32 (1991), S. 75-97 
    ISSN: 1573-5133
    Keywords: Coelacanth ; Evolution ; Phylogeny ; Cladistics ; Classification ; Intracranial joint ; Fins ; Vertebral column
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Latimeria is the product of a long coelacanth lineage, usually viewed as having changed very little. In this paper a classification of better known coelacanth genera is proposed based on a cladistic computer analysis of 56 morphological characters. Biometrical data are then matched with the classification to explore the possibility of identifying subtle change. It is concluded that throughout coelacanth history there have been changes in the structure of the vertebral column involving an overall increase in the number of vertebral elements, and a consequent crowding of these elements within the abdominal region. These changes may be associated with increasing lobation of the second dorsal and anal fins. In the skull, parameters involving the intracranial joint have also changed in such a way that the anterior part of the skull has lengthened in relation to the posterior part and this may be associated with an increase in length of the basicranial muscle.
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    Human evolution 6 (1991), S. 1-47 
    ISSN: 1824-310X
    Keywords: Femur ; Tibia ; Anthropoidea ; Morphology ; Pongids ; Early Hominids ; Evolution ; Phylogeny ; Allometry ; Multivariate analysis ; Multivariate analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Seventy six metrical traits measured on the femur and tibia of three higher primate groups —Ceboidea, Cercopithecoidea, Hominoidea have been processed by various univariate and multivariate statistical methods to survey the process of evolution of the morphology of the femur and tibia in higher primates. Intragroup and intergroup variability, similarity and differences as well as various aspects of scaling and sexual dimorphism have been analyzed to study adaptive trends and phylogenetic diversity in higher primates, in individual superfamilies and to explore the adaptive morphological pattern of early hominids and basic differences between hominids and pongids. Two basic morphotypes of the femur and tibia in higher primates have been determined. They are (1) advanced hominoid morphotype (hominids and pongids) and (2) ancestral higher primate morphotype (platyrrhine and cattarrhine monkeys, early hominoids, and hylobatids). Cebid lower limb bones are adapted to arboreal quadrupedalism with antipronograde features while femur and tibia of cercopithecid monkeys are basically adapted to the semi-arboreal locomotion. Early hominoids (Proconsul) and hylobatids are morphologically different from pongids; some features are close toAteles or other monkey species. Pongids and hominids are taken as one major morphological group with different scaling and some functional and morphological similarities. Numerous analogous features were described on the lower limb skeleton ofPan andPongo showing analogous ecological parameters in their evolution. Major morphological and biomechanical trends are analyzed. It is argued that early advanced hominoid morphology is ancestral both to the pongids and to early hominids. The progressive morphological trend in early hominids has been found fromA. afarensis with ancestral hominid morphology, toH. habilis with an elongated femur and structural features similar to advanced hominids. A detailed phylogenetic analysis of higher primate femur and tibia is also presented.
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    Journal for general philosophy of science 21 (1990), S. 309-328 
    ISSN: 1572-8587
    Keywords: Evolution ; evolutionäre Erkenntnistheorie ; Organismus ; Autonomie ; Abbildungskritik
    Source: Springer Online Journal Archives 1860-2000
    Topics: Philosophy , Nature of Science, Research, Systems of Higher Education, Museum Science
    Notes: Summary The concept of evolutionary epistemology has been critically discussed by philosophers who have mainly pointed to unacceptable philosophical tenets (cf. Vittorio Hösle, this Journal, Vol. 19 (1988), pp. 348–377). However, as most philosophers are extremely reluctant to critically treat the biological theories on which the ideas of evolutionary epistemology are based, the invalid concepts of adaption escaped their critical scrutiny. Therefore the influence of preconceived biological theories on the biological basis of evolutionary epistemology and the distorting consequences on the philosophical level could not be elaborated. The following context sketches a new view of organismic reasoning and its impact on evolutionary aspects of epistemology. The basic theorem of adaptation is shown to be unacceptable and invalid if organisms are conceived as autonomous entities which can only evolve according to their specific internal organismic properties.
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    Biology and fertility of soils 9 (1990), S. 110-118 
    ISSN: 1432-0789
    Keywords: Kuehneltiella terricola gen. nov., sp. nov. ; Soil ciliates ; Colpodidae ; Systematics ; Evolution ; Australia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The morphology and biology of the colpodid ciliate Kuehneltiella terricola gen. nov., sp. nov. has been investigated using living organisms, various silver impregnation methods, and scanning electron microscopy. The new species has been isolated in soil from central Australia and might be endemic to this continent. The new genus Kuehneltiella differs from its nearest relative, Bresslaua, in having a right oral polykinetid composed of a single row of dikinetids. A reinvestigation of Lynn's slides of Bresslaua insidiatrix showed that, contrary to the statement of Lynn (1979), this species has a typic colpodid right oral polykinetid, i.e., composed of many short, disordered kineties. A brief review of the literature suggests that simple, single-rowed, right oral polykinetids are apomorphic in the colpodids s. str. Further, this special character has obviously evolved independently several times within the class Colpodea and even within the colpodids s. str. An illustrated key to the genera of the family Colpodidae is provided.
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    Biology and fertility of soils 9 (1990), S. 95-100 
    ISSN: 1432-0789
    Keywords: Assulina-Valkanovia ; Testacea ; Polymorphism ; Genotypes ; Evolution ; Spruce forest ; Sphagnum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The taxonomy and evolution of the Assulina-Valkanovia complex were investigated in a spruce forest soil which included a Sphagnum plot (GDR, Thuringia). In both habitats Assulina muscorum occurred in two colour forms (brown and colourless) and four shapes. A quantified phenospectrum from Assulina muscorum was obtained. The four shapes were distributed differently between the brown and the colourless forms in Sphagnum and soil. The shell measurements showed statistically significant differences between the brown and the colourless forms. Even between the two brown populations there were some significant differences. Each of the four shape types of brown and of colourless Assulina can be kept in clonal cultures for some time. However, without selection, single cultures eventually revert to mixed types. The four shape types show different degrees of stability. These colour and shape forms are genotypes, which can also occur for short periods in the natural habitats. The brown populations in Sphagnum and in the soil were dominated by different shape types during the period of investigation. Valkanovia elegans cannot be distinguished from Assulina muscorum type 4, but Valkanovia can inhabit both upper and lower soil horizons, whereas Assulina and its forms lives exclusively in the upper horizon (litter). Valkanovia from the lower horizon is constant in clonal culture. The conclusion of the present investigation is that there are stable and unstable constellations within a changeable genome, which give asexual groups both a taxonomic structure and a continuum of forms. Selection can increase stability, by polygenic control of features.
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    Current genetics 17 (1990), S. 223-227 
    ISSN: 1432-0983
    Keywords: Orotidine-5′-phosphate decarboxylase ; Cephalosporium acremonium ; Recombinant DNA ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have cloned the Cephalosporium acremonium pyr4 gene by cross-hybridization with the equivalent gene from Neurospora crassa, the closest relative from which this gene is available. The C. acremonium pyr4 gene complements an E. coli pyrF mutant lacking orotidine-5′-phosphate decarboxylase (OMPdecase), and most probably does not contain introns. Maxicell analysis in E. coli shows that it encodes a 46 kDa polypeptide. The C. acremonium OMPdecase contains a highly conserved pentadecapeptide characteristic for this category of enzyme. Extensive sequence comparison suggests an important role of this region in enzymatic activity.
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  • 146
    ISSN: 1432-0983
    Keywords: Trypanosomes ; RNA polymerase ; Transcription ; Evolution ; Phylogeny
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have sequenced the genes encoding te largest subunits of the three classes of DNA-dependent RNA polymerases of Trypanosoma brucei. The nucleotide and deduced amino acid sequences were compared and aligned with the corresponding sequences of other eukaryotes. Phylogenetic relationships were subsequently calculated with a distant matrix, a bootstrapped parsimony and a maximum-likelihood method. These independent calculations resulted in trees with very similar topologies. The analyses show that all the largest subunits of T. brucei are evolutionarily distant members within each of the three RNA polymerase classes. An early separation of the trypanosomal subunits from the eukaryotic lineage might from the fundamental basis for the unusual transcription process of this species. Finally, all dendrograms show a separate ramification for the largest subunit of RNA polymerase I, II and III. RNA polymerase II and/or III form a bifurcation with the archaebacterial lineage. RNA polymerase I, however, arises separately from the eubacterial β′ lineage. This suggests that the three eukaryotic RNA polymerase classes are not simply derived by two gene duplications of an ancestral gene with subsequent differentiation.
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    ISSN: 1432-0983
    Keywords: Cyanophora paradoxa ; Ferredoxin-NADP+-oxidoreductase ; Protein-import ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Cyanophora paradoxa is an important model organism for the study of the transition from endocytobiontic cyanobacteria to factual eukaryotic cell organelles. The cyanelles of these organisms possess cyanobacterial, as well as plastidic, characteristics. Although the transfer of cyanellar proteins from cytosolic into cyanellar space has been shown, the process of translocation of a known protein across the peptidoglycan layer and the envelope membranes has not been characterized. In this study we demonstrate that a specific and obligate cyanelle protein —Ferredoxin-NADP+-oxidoreductase (FNR) — is coded on the nuclear genome, synthesized on 80S ribosomes and transported from the eukaryotic cell compartment into the cyanelles of Cyanophora paradoxa, an original intracellular host-guest relation. These results indicate a gene transfer from guest to host genome and support the view that, in spite of their cyanobacterial origin, cyanelles have been evolved to cell organelles comparable to plastids.
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    Journal of molecular evolution 30 (1990), S. 489-492 
    ISSN: 1432-1432
    Keywords: Actinomyces ; Phosphotransferase ; Aminoglycoside ; Phylogenetic tree ; Evolution
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    Topics: Biology
    Notes: Summary The protein sequences of seven 3′-aminoglycoside phosphotransferases falling into the six identified types and three 6′-aminoglycoside phosphotransferases were analyzed to give a rooted phylogenetic tree. This tree supports the origin of these groups of enzymes in an ancestor closely related to the actinomycetes, and that horizontal transfer of the resistance genes occurred, possibly via transposons. The implications for genetic engineering of a novel antibiotic are discussed.
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  • 149
    ISSN: 1432-1432
    Keywords: Mitochondrial DNA ; Evolution ; Echinoderms ; Sea stars ; DNA sequence ; Mitochondrial proteins ; Mitochondrial tRNA genes
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    Notes: Summary We have cloned and sequenced over 9 kb of the mitochondrial genome from the sea starPisaster ochraceus. Within a continuous 8.0-kb fragment are located the genes for NADH dehydrogenase subunits 1, 2, 3, and 4L (ND1, ND2, ND3, and ND4L), cytochrome oxidase subunits I, II, and III (COI, COII, and COIII), and adenosine triphosphatase subunits 6 and 8 (ATPase 6 and ATPase 8). This large fragment also contains a cluster of 13 tRNA genes between ND1 and COI as well as the genes for isoleucine tRNA between ND1 and ND2, arginine tRNA between COI and ND4L, lysine tRNA between COII and ATPase 8, and the serine (UCN) tRNA between COIII and ND3. The genes for the other five tRNAs lie outside this fragment. The gene for phenylalanine tRNA is located between cytochrome b and the 12S ribosomal genes. The genes for tRNAglu and tRNAthr are 3′ to the 12S ribosomal gene. The tRNAs for histidine and serine (AGN) are adjacent to each other and lie between ND4 and ND5. These data confirm the novel gene order in mitochondrial DNA (mtDNA) of sea stars and delineate additional distinctions between the sea star and other mtDNA molecules.
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  • 150
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    Journal of molecular evolution 30 (1990), S. 60-71 
    ISSN: 1432-1432
    Keywords: Cysteine endopeptidase ; Cysteine proteinase ; Inhibitor ; Cystatin ; Kininogen ; Evolution ; Amino acid sequence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have examined the amino acid sequences of a number of proteins that have been suggested to be related to chicken cystatin, a protein from chicken egg white that inhibits cysteine proteinases. On the basis of statistical analysis, the following proteins were found to be members of the cystatin superfamily: human cystatin A, rat cystatin A(α), human cystatin B, rat cystatin B(β), rice cystatin, human cystatin C, ox colostrum cystatin, human cystatin S, human cystatin SA, human cystatin SN, chicken cystatin, puff adder cystatin, human kininogen, ox kininogen, rat kininogen, rat T-kininogens 1 and 2, human α2HS-glycoprotein, and human histidine-rich glycoprotein. Fibronectin is shown not to be a member of this superfamily, and the c-Ha-ras oncogene protein p21(Val-12) probably is not a member also. It was convenient to divide members of the superfamily into four types on the basis of the presence of one, two, or three copies of cystatin-like segments and the presence or absence of disulfide bonds. Evolutionary dendrograms were calculated by three methods, and from these we have constructed a scheme depicting the sequence of events in the evolution of these proteins. We suggest that about 1000 million years ago a precursor containing disulfide loops appeared, and that all disulfide-containing cystatins are derived from this. We follow the evolution of the proteins of the superfamily along four main lineages, with special attention to the part that duplication of segments has played in the development of the more complex molecules.
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  • 151
    ISSN: 1432-1432
    Keywords: Drosophila melanogaster ; Evolution ; Hybrid dysgenesis ; I elements ; Transposons
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    Notes: Summary There are two categories of strains inDrosophila melanogaster with respect to the I-R system of hybrid dysgenesis. The inducer strains contain particular transposable elements named I factors. They are not present in the strains of the other category called reactive (R) strains. Defective I elements are present in the pericentromeric regions of both categories of strains. This last subfamily of I sequences has not yet been described in detail and little is known about its origin. In this paper, we report that the defective I elements display an average of 94% of sequence identity with each other and with the transposable I factor. The results suggest that they cannot be the progenitors of the present day I factors, but that each of these two subfamilies started to evolve independently several million years ago. Furthermore, the sequence comparison of these I elements with an active I factor fromDrosophila teissieri provides useful information about when the deleted I elements became immobilized.
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  • 152
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    Journal of molecular evolution 30 (1990), S. 333-346 
    ISSN: 1432-1432
    Keywords: Protamine ; Evolution ; Nuclear protein ; DNA condensation ; Sperm proteins
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    Topics: Biology
    Notes: Summary The availability of the amino acid sequence for nine different mammalian P1 family protamines and the revised amino acid sequence of the chicken protamine galline (Oliva and Dixon 1989) reveals a much close relationship between mammalian and avian protamines than was previously thought (Nakano et al. 1976). Dot matrix analysis of all protamine genes for which genomic DNA or cDNA sequence is available reveals both marked sequence similarities in the mammalian protamine gene family and internal repeated sequences in the chicken protamine gene. The detailed alignments of the cis-acting regulatory DNA sequences shows several consensus sequence patterns, particularly the conservation of a cAMP response element (CRE) in all the protamine genes and of the regions flanking the TATA box, CAP site, N-terminal coding region, and polyadenylation signal. In addition we have found a high frequency of the CA dinucleotide immediately adjacent to the CRE element of both the protamine genes and the testis transition proteins, a feature not present in other genes, which suggests the existence of an extended CRE motif involved in the coordinate expression of protamine and transition protein genes during spermatogenesis. Overall these findings suggest the existence of an avian-mammalian P1 protamine gene line and are discussed in the context of different hypotheses for protamine gene evolution and regulation.
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  • 153
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    Journal of molecular evolution 30 (1990), S. 409-424 
    ISSN: 1432-1432
    Keywords: Phylogeny ; Tetrapods ; Morphology ; Cladistics ; Divergence ; Evolution ; Amphibians ; Reptiles ; Birds ; Mammals
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Summary The phylogeny of the major groups of tetrapods (amphibians, reptiles, birds, and mammals) has until recently been poorly understood. Cladistic analyses of morphological data are producing new hypotheses concerning the relationships of the major groups, with a focus on the identification of monophyletic groups. Molecular phylogenies support some of these views and dispute others. Geological dates of the major evolutionary branching points are recalculated on the basis of the cladograms and new fossil finds.
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  • 154
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    Journal of molecular evolution 31 (1990), S. 3-9 
    ISSN: 1432-1432
    Keywords: Caenorhabditis elegans ; Caenorhabditis briggsae ; hsp70 ; grp78 ; Gene comparison ; Evolution ; Regulatory elements
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    Notes: Summary Caenorhabditis elegans andCaenorhabditis briggsae are two closely related nematode species that are nearly identical morphologically. Interspecific cross-hybridizing DNA appears to be restricted primarily to coding regions. We compared portions of thehsp-3 homologs two grp 78-like genes, fromC. elegans andC. briggsae and detected regions of DNA identity in the coding region, the 5′ flanking DNAs, and the introns. Thehsp-3 homologs share approximately 98% and 93% identity at the amino acid and nucleotide levels, respectively. Using the nucleotide substitution rate at the silent third position of the codons, we have estimated a lower limit for the date of divergence betweenC. elegans andC. briggsae to be approximately 23–32 million years ago. The 5′ flanking DNAs and one of the introns contain elements that are highly conserved betweenC. elegans andC. briggsae. Some of the regions of nucleotide identity in the 5′ flanking DNAs correspond to previously detected identities including viral enhancer sequences, a heat shock element, and an element present in the regulatory regions of mammalian grp78 and grp94 genes. We propose that a comparison ofC. elegans andC. briggsae sequences will be useful in the detection of potential regulatory and structural elements.
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  • 155
    ISSN: 1432-1432
    Keywords: Archaebacteria ; rRNA operons ; Secondary structure ; Evolution
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    Notes: Summary Several sequences flanking the large rRNA genes of several transcripts from extreme thermophiles, extreme halophiles, and methanogens were aligned and analyzed for the presence of common primary and secondary structural features, which would bear on the concept of monphyletic archaebacteria. Few sequences were common to all the archaebacterial transcripts, and these were confined to short regions generally flanking putative double helices. At a secondary structural level, however, in addition to the previously characterized processing stems of the 16S and 23S RNAs, four helices were detected that were common to the archaebacterial transcripts: two in the 16S RNA leader sequence and two in the 16S-23S RNA spacer. Although all of these helices vary in size and form from organism to organism, three of them contain double helical segments that are strongly supported by compensating base changes among the three archaebacterial groups. Three extreme halophiles exhibited two additional helices in their relatively large spacers and a further helix preceding the 5S RNA, which are also supported by compensating base changes. Ribosomal RNA transcripts from eubateria/chloroplasts and eukaryotes were also examined for secondary structural features with locations and forms corresponding to those of the archaebacteria, but none were detected. The analysis provides support for the monophyletic nature of the archaebacteria and reinforces their differences from eubacteria/chloroplasts and eukaryotes.
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  • 156
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    Journal of molecular evolution 31 (1990), S. 205-210 
    ISSN: 1432-1432
    Keywords: Isozyme ; Intron ; Phylogenetic tree ; Evolution
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    Notes: Summary Both the mouse cytosolic malate dehydrogenase gene and its mitochondrial counterpart contain eight introns, of which two are present at identical positions between the isozyme genes. The probability that the two intron positions coincide by chance between the two genes has been shown to be significantly small (=1.3×10−3), suggesting that the conservation of the intron positions has a biological significance. On the basis of a rooted phylogenetic tree inferred from a comparison of these isozymes and lactate dehydrogenases, we have shown that the origins of the conserved introns are very old, possibly going back to a date before the divergence of eubacteria, archaebacteria, and eukaryotes. In the aspartate aminotransferase isozyme genes, five of the introns are at identical places. The origins of the five conserved introns, however, are not obvious at present. It remains possible that some or all of the conserved introns have evolved after the divergence of eubacteria and eukaryotes.
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  • 157
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    Journal of molecular evolution 31 (1990), S. 325-329 
    ISSN: 1432-1432
    Keywords: PLP-dependent decarboxylase ; Evolution ; Profile analysis
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    Notes: Summary A database search has revealed significant and extensive sequence similarities among prokaryotic and eukaryotic pyridoxal phosphate (PLP)-dependent decarboxylases, includingDrosophila glutamic acid decarboxylase (GAD) and bacterial histidine decarboxylase (HDC). Based on these findings, the sequences of seven PLP-dependent decarboxylases from five different organisms have been aligned to derive a consensus sequence for this family of enzymes. In addition, quantitative methods have been employed to calculate the relative evolutionary distances between pairs of the decarboxylases comprising this family. The multiple sequence analysis together with the quantitative results strongly suggest an ancient and common origin for all PLP-dependent decarboxylases. This analysis also indicates that prokaryotic and eukaryotic HDC activities evolved independently. Finally, a sensitive search algorithm (PROFILE) was unable to detect additional members of this decarboxylase family in protein sequence databases.
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  • 158
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    Journal of molecular evolution 31 (1990), S. 485-492 
    ISSN: 1432-1432
    Keywords: BK virus ; Strains ; Regulatory region ; Late region ; Nucleotide sequence ; Evolution
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    Notes: Summary Within the genome of human polyomavirus BK (BKV), there exists a noncoding regulatory region toward the late region side of the origin of DNA replication. In most BKV strains isolated by viral culture, this regulatory region contains tandem repeats varying in size. Recently. however, several laboratories isolated new BKV strains (designated as archetypal strains) lacking such repeat sequences. To examine the genetic relationship between archetypal strains, a phylogenetic tree was constructed for seven BKV strains, including three archetypal strains, from DNA sequence data on the late genes, those for leader protein (agnoprotein), and those for structural proteins (VP1, VP2, and VP3). For three strains data previously reported were used, whereas for the others sequences were determined in this study. From total numbers of nucleotide substitutions in each pair of strains, a phylogenetic tree was constructed by the unweighted pair-group method. The phylogenetic tree obtained reveals that BKV strains containing the archetypal regulatory region do not constitute a cluster of closely related strains and that these strains, together with those carrying the major part of the archetypal regulatory region, are widespread in the BKV population. This finding suggests that the basic structure of the archetypal regulatory region has been conserved in the course of BKV evolution.
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  • 159
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    Cellular and molecular life sciences 46 (1990), S. 530-533 
    ISSN: 1420-9071
    Keywords: Evolution ; genetics ; heritability ; locomotion ; physiology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Locomotor capacities and their physiological bases are thought to be of considerable selective importance in natural populations. Within this functional complex, organismal performance traits (e.g., speed, stamina) are expected to be of more direct selective importance than their suborganismal determinants (e.g., heart size). Quantitative genetics theory predicts that traits of greater selective importance should generally have lower heritabilities at equilibrium. Contrary to these expectations, we report that organismal performance traits had the highest heritabilities in a natural population of garter snakes.
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  • 160
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    Journal of comparative physiology 167 (1990), S. 71-78 
    ISSN: 1432-1351
    Keywords: Compound eye ; Optics ; Crustacea ; Evolution
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    Topics: Biology , Medicine
    Notes: Summary Compound eyes of the decapod shrimp Gennadas, the hermit crab Dardanus, and the syncarid crustacean Anaspides are studied histologically and with optical experiments. The results demonstrate that these three crustaceans all have refracting superposition eyes. The conclusion is based on the following observations: 1. There is a wide clear-zone, which allows for a superposition image to be formed. 2. Dark-adapted eyes display a large eye-glow, and the ommatidia are not optically isolated. 3. The crystalline cones have the shape typical for refracting superposition eyes, and they contain the required lens-cylinder gradient of refractive index. Euphausiids and mysids were previously thought to be the only crustaceans with refracting superposition eyes, whereas the species investigated here were assumed to have reflecting superposition eyes (decapod shrimps) or apposition eyes (hermit crabs and syncarids). The present findings increase more than twofold the number of crustacean groups that are known to have developed refracting superposition optics. It also provides insight into the evolutionary mechanisms that may have led to the development of this type of imaging optics.
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  • 161
    ISSN: 1432-072X
    Keywords: Oligotrophic bacteria ; Caulobacter ; “Hyphobacter” ; Hyphomonas ; Hyphomicrobium ; Antibiotic sensitivity ; Evolution ; Fatty acids ; Lipids ; Taxonomy
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    Topics: Biology
    Notes: Abstract A new approach was developed for the determination of taxonomic and evolutional relationships among four genera of oligotrophic bacteria. The main idea of this approach is the algorithmized integrative analysis of the morphological and physiological specificity of these bacteria, their 5S rRNA sequences, fatty acid and lipid composition of their membranes, as well as their sensitivity to a large variety of antibiotics. It was shown that the genera Caulobacter and Hyphomonas are closely related to each other, but they are both distant from Hyphomicrobium species. The new genus, “Hyphobacter”, is placed between Caulobacter and Hyphomonas. Taxonomic heterogeneity was found to exist within the genera Caulobacter and Hyphomicrobium. Evolutional pathways from Caulobacter to Hyphomicrobium are proposed on the basis of the present data. No correlations were found between the cell morphology of the organisms and their geno-and chemotaxonomy.
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  • 162
    ISSN: 1432-072X
    Keywords: Eubacterium ; Thermophile ; Evolution ; Fervidobacterium ; Lipids ; Thermotoga
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    Notes: Abstract An extremely thermophilic anaerobic fermentative eubacterium growing at temperatures between 50 and 80°C (opt.: 65°C) was isolated from an Icelandic hot spring. The cells were Gram-negative motile rods, about 1.8 μm in length, and 0.6 μm in width occurring singly and in pairs. About 50% of the cells formed large spheroids at one end similar to Fervidobacterium nodosum. The new isolate H 21 differed from Fervidobacterium nodosum by a 6 mol % higher GC-content of its DNA (41 mol %), its ability to grow on cellulose, and insignificant DNA homology. The lipids of isolate H 21 were similar to that of members of “Thermotogales”. 16S rRNA sequencing of isolate H 21 and Fervidobacterium nodosum indicated (a) that isolate H 21 represents a new species of the genus Fervidobacterium which we name Fervidobacterium islandicum and (b) that the genus Fervidobacterium belongs to the “Thermotogales” branch.
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    Journal of mathematical biology 28 (1990), S. 237-256 
    ISSN: 1432-1416
    Keywords: Behavior ; Evolution ; Neural network ; Dynamic optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Abstract One of the main challenges to the adaptionist program in general and the use of optimization models in behavioral and evolutionary ecology, in particular, is that organisms are so constrained' by ontogeny and phylogeny that they may not be able to attain optimal solutions, however those are defined. This paper responds to the challenge through the comparison of optimality and neural network models for the behavior of an individual polychaete worm. The evolutionary optimization model is used to compute behaviors (movement in and out of a tube) that maximize a measure of Darwinian fitness based on individual survival and reproduction. The neural network involves motor, sensory, energetic reserve and clock neuronal groups. Ontogeny of the neural network is the change of connections of a single individual in response to its experiences in the environment. Evolution of the neural network is the natural selection of initial values of connections between groups and learning rules for changing connections. Taken together, these can be viewed as “design parameters”. The best neural networks have fitnesses between 85% and 99% of the fitness of the evolutionary optimization model. More complicated models for polychaete worms are discussed. Formulation of a neural network model for host acceptance decisions by tephritid fruit flies leads to predictions about the neurobiology of the flies. The general conclusion is that neural networks appear to be sufficiently rich and plastic that even weak evolution of design parameters may be sufficient for organisms to achieve behaviors that give fitnesses close to the evolutionary optimal fitness, particularly if the behaviors are relatively simple.
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    Theoretical and applied genetics 79 (1990), S. 397-400 
    ISSN: 1432-2242
    Keywords: Durum wheat ; C-banding ; Homoeologous pairing ; Chromosome structure ; Evolution
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    Topics: Biology
    Notes: Summary Meiotic pairing was analyzed at metaphase I in ABRR triticale × rye hybrids to identify the arm homoeology of chromosomes ofTriticum turgidum. Wheat chromosomes were identified using a C-banding technique. Results confirmed that the homoeologous relationships between chromosome arms of the A and B genomes inT. turgidum are the same as inT. aestivum, and that a double translocation involving4AL,5AL, and7BS is present inT. turgidum. It is proposed that a pericentric inversion involving a substantial portion of chromosome4A is present inT. turgidum andT. aestivum.
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    Theoretical and applied genetics 80 (1990), S. 296-304 
    ISSN: 1432-2242
    Keywords: Sorghum ; Isozyme ; Genetic diversity ; Evolution ; Systematics
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    Topics: Biology
    Notes: Summary A survey of allozyme variation among the spontaneous taxa of Sorghum section Sorghum was undertaken. Eight plants each of 90 accessions representing the diploid S. bicolor (ssp. arundinaceum and drummondii) and the tetraploids S. almum and S. halepense were analyzed for 17 enzyme systems encoded by 30 loci. Low levels of variation were found within and among accessions, although there was more variation than is typical of inbreeding species. We found an average of 3.2 alleles per locus in ssp. arundinaceum, with a mean expected heterozygosity for the accessions of 0.034 and total panmictic heterozygosity of 0.154. An analysis of the apportionment of genetic variation among accessions of ssp. arundinaceum indicated that 26% of the variation occurs within accessions and 74% among accessions. Cultivated sorghum contains far less allozymic variation than ssp. arundinaceum, its presumed progenitor. This is consistent with the prediction that cultivated sorghum experienced a loss of genetic variation during domestication. For the most part, cultivated sorghum contains a subset of the allozymes found in ssp. arundinaceum. Principal component analysis revealed continuous variation among the accessions and geographic regions, with accessions failing to segregate into discrete clusters. However, accessions of race virgatum of ssp. arundinaceum occupied one end of the continuum and were, in that sense, distinguished from the other accessions. Similarly, most accessions of S. halepense and S. almum occupied the central portion of the continuum. The allozymic data presented here are consistent with the hypothesized origin of S. halepense via autopolyploidy or segmental allopolyploidy.
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    Theoretical and applied genetics 80 (1990), S. 641-647 
    ISSN: 1432-2242
    Keywords: Pinus ; Species hybridization ; Chloroplast DNA ; Molecular markers ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Restriction fragment analysis and heterologous hybridization of chloroplast (cp) DNA was used to develop species-specific markers for P. tabulaeformis, P. yunnanensis and P. massoniana. Fragment patterns created by the BclI and DraI restriction enzymes and hybridization patterns to the psbC and psbD probes were distinctive among the three species. No intraspecific variation was detected with respect to any of the cpDNA markers developed in this study. The cpDNA markers obtained were subsequently used to examine the parentage of P. densata, a putative Tertiary hybrid between P. tabulaeformis and P. yunnanensis. The analysis demonstrated for the first time that P. densata populations accommodate chloroplast genomes of P. tabulaeformis and P. yunnanensis, which strongly supports earlier suggestions of the hybrid origin of this species. It appears that P. densata represents a stabilized natural hybrid that has become adapted to high mountain environments where neither of the parental species can normally grow.
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    Theoretical and applied genetics 80 (1990), S. 635-640 
    ISSN: 1432-2242
    Keywords: Pinus ; Species hybridization ; Allozymes ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Allozyme differentiation at 13 loci was studied in populations of Pinus tabulaeformis, P. densata, and P. yunnanensis from China. It was previously suggested that P. densata represents a Tertiary hybrid between P. tabulaeformis and P. yunnanensis. The observed levels of allozyme variation within and among the investigated species were comparable to those of other conifers. P. tabulaeformis differed markedly from P. yunnanensis with respect to allozyme frequencies, while P. densata was intermediate between the two putative parents. There was evidence of homozygote excess in embryos from all investigated species, as compared to Hardy-Weinberg expectations. The observed allozyme composition of P. densata conformed to earlier morphological and molecular evidence indicating hybrid origin of this taxon. It was proposed that fusion of gene pools from P. tabulaeformis and P. yunnanensis has led to adaptive evolution of a new species, P. densata.
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  • 168
    ISSN: 1615-6102
    Keywords: Basal-body root complex ; Cell division cycle ; Centrosome ; Chlamydomonas ; Evolution ; Monoclonal antibody
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    Topics: Biology
    Notes: Summary The mammalian centrosome monoclonal antibody MPM-13 recognized component(s) of the well defined MTOC basal-body root complex in the green plantChlamydomonas. The antibody reaction coincided in location with the basal-body root complex and the cruciate nature of the staining pattern corresponded to the configuration of the root microtubules. During mitosis the behaviour of MPM-13 stained material mirrored the duplication, separation and migration to the spindle poles of the basal body-root complex. It is suggested that conserved MTOC components were recognized and that these may have retained a similar, perhaps universal, function in microtubule organization.
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    Evolutionary ecology 4 (1990), S. 130-142 
    ISSN: 1573-8477
    Keywords: Evolution ; Darwin's finches ; extinction ; Geospizinae ; island biogeography ; ecological isolation ; reproductive isolation ; speciation ; taxon cycle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The Hamilton-Rubinoff model of evolution in the avifauna of the Galapagos Islands suggests that speciation occurs on small outlying islands, and that new species invade the central island region, where ecological differentiation takes place. I present an alternative model in which both speciation and ecological differentiation leading to origin of actively colonizing taxa occur on the large islands, with colonization of small and outlying islands being primarily one way. Although forms on outlying islands may differentiate to the level of new species, their fate is postulated to be extinction rather than re-invasion of central islands. Data on species with expanding, differentiating, fragmenting, and relict distributions support this second model. Polytypy and incompleteness of distributions on the large islands indicate that isolation is adequate for differentiation to occur. Distributions of expanding taxa centre on the large islands, and their distributions show sequences leading from large islands to smaller and more outlying islands. Curves of occupancy of large islands versus total islands also agree with the prediction that expansions begin in the large islands.
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  • 170
    ISSN: 1617-4623
    Keywords: Flaveria ; C3/C4 plants ; Phosphoenolpyruvate carboxylase ; Gene family ; Evolution
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    Topics: Biology
    Notes: Summary Phosphoenolpyruvate carboxylase (PEPCase) was shown to be encoded by a multigene family in various Flaveria species analysed. Several clones were isolated from genomic libraries of F. pringlei (C3 species) and F. trinervia (C4 species) and classified into four distinct groups according to their hybridization behaviour to a full-length cDNA clone encoding the PEPCase C4 isozyme of F. trinervia. A detailed cross-hybridization analysis demonstrated that the closest relative of most of the PEPCase genes isolated from F. trinervia and F. pringlei was not found in the same but in the other species. Northern analysis, using stringent conditions, allowed discrimination of class-specific PEPCase transcripts and revealed characteristic organ-specific expression patterns.
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  • 171
    ISSN: 1617-4623
    Keywords: Aspergillus nidulans ; Gene regulation ; amdS gene ; Evolution
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    Topics: Biology
    Notes: Summary In Aspergillus nidulans expression of the acetamidase structural gene, amdS, is under the control of at least four regulatory genes including the trans-acting amdA regulatory gene. A cis-acting mutation (amdI66) consisting of an 18 by duplication in the 5′ region of the amdS gene results in very high levels of acetamidase activity but only in strains carrying semi-dominant mutations in the amdA gene. In selecting for increased amdS expression in an amdI66 amdA – strain, an A. nidulans strain with a mutation in the 5′ region of the amdS gene was isolated. The nucleotide sequence was determined of the region containing the mutation, designated amdI666. The mutant strain carries three tandem copies of the 18 by sequence that is duplicated in the amdI66 mutation. Thus, from a strain carrying a duplication of an apparent regulatory protein binding site with little effect on gene expression, a strain has been derived that carries a triplication of the site with consequent major effects on regulation. The multiple copies of regulatory sites present in many genes may have been generated by a similar mechanism.
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    Molecular genetics and genomics 221 (1990), S. 315-321 
    ISSN: 1617-4623
    Keywords: Small stable RNA ; Signal recognition particle ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The genes encoding the 7S RNAs of the archaebacteria Archaeoglobus fulgidus, Methanosarcina acetivorans, Sulfolobus solfataricus, and Thermococcus celer have been isolated. All four genes occur as single genomic copies and are flanked by sequences containing potential signals for transcriptional promotion and termination. The genes encode RNA molecules approximately 300 nucleotides in length which conform strictly to a model of secondary structure common to all described archaebacterial 7S RNAs. Archaebacterial 7S RNAs exhibit a strong similarity to eukaryotic 7S RNAs in terms of overall secondary structure, while primary sequence conservation is limited to a specific structural domain of the molecule. This domain displays strong primary and secondary structural similarity to features of small eubacterial RNAs, including the small cytoplasmic (sc) RNA of Bacillus subtilis and the 4.5S RNA of Escherichia coli. Conservation of this structural domain among divergent RNA molecules across three kingdoms suggests that these RNAs are the descendants of a unique subcellular structure present before the divergence of the archaebacterial, eubacterial and eukaryotic kingdoms.
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  • 173
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    Environmental biology of fishes 28 (1990), S. 33-75 
    ISSN: 1573-5133
    Keywords: Sharks ; Rays ; Chimaeras ; Chondrichthyes ; Evolution ; Success ; Diversity ; Ecology ; Ecomorphotypes ; Reproductive modes ; Conservation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Cartilaginous fishes, the sharks, rays and chimaeras (class Chondrichthyes), are a very old and successful group of jawed fishes that currently contains between 900 and 1100 known living species. Chondrichthyians show a high morphological diversity during most of their evolutionary career from the Paleozoic to the present day. They are relatively large predators which have remained a major, competitive element of marine ecosystems despite the varied rivalry of numerous other marine vertebrate groups over at least 400 million years. Although restricted in their ecological roles by morphology, reproduction and other factors, the living cartilaginous fishes are highly diverse and show numerous alternative life-history styles which are multiple answers to exploiting available niches permitted by chondrichthyian limitations. Chondrichthyians living and fossil can be divided into at least eighteen ecomorphotypes, of which the littoral ecomorphotype is perhaps the most primitive and can serve as an evolutionary origin for numerous specialist ecomorphotypes with benthic, high-speed, superpredatory, deep-slope and oceanic components. Reproductive modes in cartilaginous fishes are of six types, ranging from primitive extended oviparity through retained oviparity and yolk-sac viviparity (previously ovoviviparity) to three derived forms of viviparity. Reproductive modes are not strongly correlated with ecomorphotypes and with the phylogeny of living elasmobranchs. The success and importance of cartilaginous fishes is largely underrated by marine biologists and by the public, and requires new and ‘heretical’ emphasis to overcome the present inadequacies of chondrichthyian research and the problems of overexploitation that cartilaginous fishes face.
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  • 174
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    Environmental biology of fishes 28 (1990), S. 87-100 
    ISSN: 1573-5133
    Keywords: Evolution ; Speciation ; Stabilizing selection ; Mbuna ; Cyrtocara ; Mouthbrooding ; Mate recognition ; Haplochromine ; Tilapiine ; Cuckoo ; Parental care ; Co-operative care
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis About 50% of African cichlid species have been described. Little is known about cichlid ecology, behaviour or about the evolution and interactions of communities. Nevertheless, trends which provide an insight into cichlid life histories, into evolutionary alternatives and into behavioural alternatives which may be followed during the life time of these fishes are emerging. Cichlids which spend their entire life history in a single habitat belong to species flocks that have spectated greatly. In contrast, those groups which live in a variety of habitats during their life history have spectated little. Despite the trophic specializations that have occurred among cichlids, many and perhaps all species, have the ability to feed upon alternative food resources. They do so by switching or by markedly modifying their behaviour and all are particularly opportunistic. The extensive adaptive radiation of cichlids with regard to those attributes of morphology and behaviour that are associated with survival and growth, is apparently not matched by similar radiations in reproductive behaviour. The perceived evolutionary conservatism with regard to reproductive behaviour is attributed to the effects of stabilizing selection, but this still needs to be tested. The constraints of stabilizing selection appear to be lifted with regard to coloration. If colour is an important component of the specific-mate recognition system then it should also be subjected to stabilizing selection so the readiness with which colour variation occurs within and between populations needs explanation. Parental care in cichlids has followed a variety of evolutionary alternatives, all of which are geared to improve the chances of survival of offspring in their specific micro-habitats.
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    Environmental biology of fishes 28 (1990), S. 77-85 
    ISSN: 1573-5133
    Keywords: Evolution ; Egg production ; Survival ; Iteroparity ; Monte Carlo simulation ; Reproduction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Marine fish species with planktonic larval stages experience high and variable pre-adult mortality, and in accordance with general life-history theory have evolved iteroparity to reduce the uncertainty in reproductive success of individuals. In this paper we use a Monte Carlo model to explore the influence of spawning style and adult survival of clupeoids on the spawning success of individual fish during their life span, when early stage survival is determined according to different spectra of environmental variability. In these simulations the variation in reproductive success was governed first by the number of batches of eggs spawned by each adult fish over its lifespan (as determined by its pattern of spawning and the adult survival rate), and secondly by the patterning of environmental variability affecting early stage survival. We consider that the life history styles of the clupeoids are based on co-evolved traits in which the different patterns of iteroparity represent different solutions for coping with the variable nature of early-stage survival. When these life history traits are compared on time scales appropriate to each species, they are therefore unlikely to provide the correlation between brood strength variation and the life span of adults proposed in Murphy's (1968) contribution to this aspect of life history theory.
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    Environmental biology of fishes 28 (1990), S. 273-284 
    ISSN: 1573-5133
    Keywords: Cichlids ; Epigamic selection ; Courtship behavior ; Species recognition ; Mate choice ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis The cichlid species flocks of the African Great Lakes represent the most extreme case of adaptive radiation among vertebrates. Recently, attention has focused on the potential for sexual selection to drive or accelerate speciation in these fishes. Cichlids as a whole are social in nature and display complex behavior, particularly during courtship and spawning; however, the extent to which changes in species recognition cues may account for species diversity among haplochromine lineages has remained speculative. Our investigations have indicated that oral incubating haplochromines show a reduction in diversity and extent of courtship relative to substrate brooding cichlids, and apparently retain aspects of a primitive specific mate recognition system. Laboratory observations of courtship in the Malawian endemicPseudotropheus zebra suggest that organization of the spawning bout is loose, and lacking in any well defined stimulus-response chain. Interspecific comparisons of in situ courtship behavior among male mbuna, lithophilous haplochromines of Lake Malawi, revealed only one potential example of species-specific behavior, and indicated that mate choice occurred prior to the onset of intense courtship. Courtship display by male mbuna does not appear critical to species recognition and may represent an evolutionary relict. Alternatively, male courtship display may have an indirect effect on successful reproduction or may be maintained through pleiotropic effects. The mbuna display no evidence of behavioral innovation and show limited interspecific differentiation in behavioral expression. More generally, there is no evidence at present to suggest that epigamic sexual selection, acting on courtship behavior, has been a major mechanism in the diversification of the haplochromine species flocks.
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    Journal of comparative physiology 159 (1990), S. 761-769 
    ISSN: 1432-136X
    Keywords: Crocodile ; Lung ; Morphometry ; Strategy ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The respiratory surface area (SAR) per kilogram body mass (MB), the harmonic mean thickness of the air-blood barrier (τhtR) in the gas exchange tissue, and the anatomical diffusion factor (ADF=SAR/τhtR per MB) were calculated for four juvenile Nile crocodiles. The ADF of three small specimens (mean MB=3.59 kg) was 625 cm2·μm−1·kg−1. The values varied considerably among individuals and were similar to that of a 5.68-kg specimen (593 cm2·μm−1·kg−1). Only 9% of the ADF is located in the anterior third of the lung, which because of its conical shape makes up only 14 percent of the total lung volume. Particularly in the middle third of the lung, the proximal region near the intrapulmonary bronchus displays a greater ratio of respiratory/non-respiratory surface areas than do more distally located sampling sites. The τhtR is also significantly smaller proximally than distally. The cumulative ADF per unit MB is greater than that previously reported for this species on the basis of overall estimates of SAR and τhtR, but is still less than that of lizards and testudinids. The disposition of ADF between distal air storage region and the intrapulmonary bronchus is consistent with a bidirectional cross-current gas exchange model.
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  • 178
    ISSN: 1824-310X
    Keywords: Creationism ; Evolution ; hominid affinity
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    Topics: Biology
    Notes: Abstract Using samples of skulls of early and modern hominids and modern pongids we compare the plausibility of Evolutionist and Creationist viewpoints. Multivariate methods are used to assess the corollary of Creationism that all fossil specimens which Evolutionists consider to be hominids are either apes or humans. We conclude that the results of this study cannot easily be accommodated within a Creationist framework, and, therefore, contribute substantial evidence for the Evolutionist viewpoint.
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    Acta biotheoretica 33 (1984), S. 35-50 
    ISSN: 1572-8358
    Keywords: Evolution ; falsification ; Darwinism ; philosophy of science
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In this paper we discuss the epistemological positions of evolution theories. A sharp distinction is made between the theory that species evolved from common ancestors along specified lines of descent (here called “the theory of common descent”), and the theories intended as causal explanations of evolution (e.g. Lamarck's and Darwin's theory). The theory of common descent permits a large number of predictions of new results that would be improbable without evolution. For instance, (a) phylogenetic trees have been validated now; (b) the observed order in fossils of new species discovered since Darwin's time could be predicted from the theory of common descent; (c) owing to the theory of common descent, the degrees of similarity and difference in newly discovered properties of more or less related species could be predicted. Such observations can be regarded as attempts to falsify the theory of common descent. We conclude that the theory of common descent is an easily-falsifiable & often-tested & still-not-falsified theory, which is the strongest predicate a theory in an empirical science can obtain. Theories intended as causal explanations of evolution can be falsified essentially, and Lamarck's theory has been falsified actually. Several elements of Darwin's theory have been modified or falsified: new versions of a theory of evolution by natural selection are now the leading scientific theories on evolution. We have argued that the theory of common descent and Darwinism are ordinary, falsifiable scientific theories.
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    Journal of molecular evolution 21 (1984), S. 54-57 
    ISSN: 1432-1432
    Keywords: Mitochondrion ; Cytochrome C ; Rhodospirillaceae ; Endosymbiosis ; rRNA ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The comparative morphology and pigmentation of protists suggest that those with tubular mitochondrial cristae belong to a different lineage than those with lamellar cristae and that the evolutionary divergence might have been very early. We propose that the difference in cristal morphology is the result of separate origins of the mitochondria from endosymbionts related to the Rhodospirillaceae (purple nonsulfur bacteria) but differing in the morphology of their internal membranes. Comparisons of the cytochromes c of protists and the Rhodospirillaceae and of 16s rRNA T1 oligonucleotide catalogs in the Rhodospirillaceae do not contradict, and in fact provide support for, the idea. More extensive evidence may be lacking simply because cytochromes c have been studied in very few protists with tubular mitochondrial cristae.
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    Journal of molecular evolution 21 (1984), S. 72-75 
    ISSN: 1432-1432
    Keywords: Heat ; Rates of copy error ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Heat induces a number of premutational lesions (for example, the deamination of cytosine to uracil) in DNA and RNA. These kinds of errors occur in resting as well as replicating polynucleotides. However, an increase in temperature also raises the probability of copying error occurring in nucleic acids because of increased thermal noise in the replicative machinery. In most modern genetic systems, the majority of heat-induced lesions are efficiently repaired. It follows that the importance of heat-induced error increases as the effectiveness of repair declines. We show in this paper that the error rate of enzymatic polynucleotide copying is expected to increase monotonically with temperature. We also explore the effects of temperature variations on the early evolution of biological information transmission mechanisms.
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    Journal of molecular evolution 20 (1984), S. 128-134 
    ISSN: 1432-1432
    Keywords: Snake venom ; Neurotoxin ; Cytotoxin ; Evolution ; Circular dichroism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The amino acid sequences of the 139 homologous “short” neurotoxins, “long” neurotoxins and cytotoxins so far characterised from elapid snake venoms were compared on the basis of the amino acid deletion/insertion events that have occurred during evolution. Systematic grouping of the toxins according to similarity suggests that the short neurotoxins resemble the cytotoxins more closely than they do the long neurotoxins. The significance of this finding is discussed in relation to the methodology, the conformations of the toxins (as represented by circular dichroism spectra) and the outcome of the study that would have been obtained had more traditional methods been used. It appears probable that the cytotoxins evolved relatively recently from neurotoxic ancestors.
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  • 183
    ISSN: 1432-1432
    Keywords: Balbiani ring ; Repeat ; Evolution ; Repetitive DNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary All known types of Balbiani ring (BR) gene consist of multiple, tandemly arranged, ca. 180 to 300-bp repeat units that can be divided into a constant region and a subrepeat region. The latter region includes short tandem subrepeats (SRs). Comparison of all available BR sequences using computer methods has enabled us (a) to define more precisely the constant and subrepeat regions, (b) to infer the evolutionary relationships among the various types of BR repeats, (c) to derive a consensus approximation of an ancestral sequence from a small segment of which the highly diverse present-day SRs may have originated, and (d) to detect an underlying substructure in the constant region, evident in the consensus but not in the present-day sequences and possibly corresponding to an original 39-bp DNA segment from which the extant, giant BR sequences may have evolved. We discuss the processes of reduplication, diversification, and homogenization within the hierarchically repetitive BR sequences as examples of how a simple DNA element may evolve into a diverse family of large, protein-coding genes.
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  • 184
    ISSN: 1432-1432
    Keywords: Evolution ; Gene family ; Balbiani ring genes ; Repetitive sequences ; Structural proteins ; Protein conformation ; Polymerization
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Summary The large, repetitive Balbiani ring (BR) genes, BR 1, 2, and 6, inChironomus tentans originated from a short ancestral sequence and have all evolved according to analogous amplification schemes. We analyzed the structures of the BR-encoded secretory proteins and defined the parts that have been conserved during the evolutionary process. The BR products show striking similarities, with the BR 1 and BR 2 products being more similar to each other than to the BR 6 product. In the constant (C) region of the repeat units, 7 of the 30 amino acid residues are strictly conserved; 4 of these are the cysteine residues. The subrepeat (SR) regions of all the BR products are dominated by repeated tripeptide elements rich in proline and charged amino acid residues. Most of the amino acid replacements in both regions are conservative. Secondary structure predictions suggested that the C regions of the BR 1 and BR2 products have several elements of secondary structure: an α-helix, a β-strand, and one or two reverse turns, as in “globular structures.” The prediction for the C region of the BR 6 product is similar but lacks a β-strand. The predictions for the intervening SR regions appear less conclusive, but are clearly different from those for the C regions, and suggest regular structures not differing in their conformational elements. The SR regions evolved from an ancestor sequence similar to the C region; thus, the BR products seem to represent an example of evolution from one structure to two differently folded products. It is proposed that the alignment and polymerization of the long BR proteins could be promoted by the repetitive structure of the molecules, due to the possibility of forming disulfide bridges between half-cystine residues and electrostatic interactions between the charged residues of the SR regions. The divergence among the BR products is discussed in relation to possible functional differences among the members of the BR gene family.
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    Environmental management 8 (1984), S. 309-324 
    ISSN: 1432-1009
    Keywords: Animals ; Indicators ; Air pollution ; Ecosystem responses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract With existing and proposed air-quality regulations, ecological disasters resulting from air emissions such as those observed at Copperhill, Tennessee, and Sudbury, Ontario, are unlikely. Current air-quality standards, however, may not protect ecosystems from subacute and chronic exposure to air emissions. The encouragement of the use of coal for energy production and the development of the fossil-fuel industries, including oil shales, tar sands, and coal liquification, point to an increase and spread of fossil-fuel emissions and the potential to influence a number of natural ecosystems. This paper reviews the reported responses of ecosystems to air-borne pollutants and discusses the use of animals as indicators of ecosystem responses to these pollutants. Animal species and populations can act as important indicators of biotic and abiotic responses of aquatic and terrestrial ecosystems. These responses can indicate long-term trends in ecosystem health and productivity, chemical cycling, genetics, and regulation. For short-term trends, fish and wildlife also serve as monitors of changes in community structure, signaling food-web contamination, as well as providing a measure of ecosystem vitality. Information is presented to show not only the importance of animals as indicators of ecosystem responses to air-quality degradation, but also their value as air-pollution indices, that is, as air-quality-related values (AQRV), required in current air-pollution regulation.
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  • 186
    ISSN: 1432-0983
    Keywords: Plastid DNA ; Cytochrome b6 gene ; Amino acid sequence ; Hydropathy ; Thylakoid membrane ; Transcript modification ; Evolution ; Spinach
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A 2.4 kilobase-pair segment of the spinach plastid chromosome carrying the genes for apocytochrome b6 and subunit 4 of the thylakoid membrane cytochrome b/f complex has been analysed by DNA sequencing and Northern blot analysis. The nucleotide sequence reveals two uninterrupted open reading frames of 211 and 139 triplets coding for two hydrophobic proteins of 23.7 kd (cytochrome b6) and 15.2 kd (subunit 4). The genes are located on the same strand and are separated from each other by 1018 untranslated base pairs. They map adjacent to the gene for the P680 chlorophyll α apoprotein of the photosystem II reaction center. The three genes appear to be under common transcriptional control and the transcripts post-transcriptionally modified. The deduced amino acid sequences of cytochrome b6 and subunit 4 both exhibit significant homology with published sequences from mitochondrial b cytochromes (42 kd) suggesting that these functionally equivalent polypeptides in photosynthetic and respiratory electron transport chains arose monophyletically.
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  • 187
    ISSN: 1432-072X
    Keywords: Superoxide dismutase ; Glutamine synthetase ; Evolution ; Marine bacteria ; Alcaligenes ; Alteromonas ; Deleya ; Oceanospirillum ; Pseudomonas
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Evolutionary relationships among marine species assigned to the genera Alteromonas, Oceanospirillum, Pseudomonas, and Alcaligenes were determined by an immunological study of their Fe-containing superoxide dismutases (FeSOD) and glutamine synthetases (GS), two enzymes with differentially conserved amino acid sequences which are useful for determining intermediate and distant relationships, respectively. Five reference antisera were prepared against the FeSODs from Alteromonas macleodii, A. haloplanktis, Oceanospirillum commune, Pseudomonas stanieri, and Deleya pacifica. For GS, a previously prepared antiserum to the enzyme from Escherichia coli was employed. Amino acid sequence similarities for both enzymes were determined by the quantitative microcomplement fixation technique and the Ouchterlony double diffusion procedure. Six evolutionary groups were detected by FeSOD sequence similarities: three subgroups within the genus Alteromonas, the genera Oceanospirillum and Pseudomonas, and a new genus, Deleya (to accommodate marine Alcaligenes). Only four groupings were delineated by the GS data: the latter three genera and one group composed of all the species of Alteromonas. Evidence that all of these subgroups are derived from the evolutionary lineage defined by the purple sulfur photosynthetic bacteria is presented.
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    Journal of mathematical biology 19 (1984), S. 329-334 
    ISSN: 1432-1416
    Keywords: Evolution ; ESS ; games ; game dynamics ; n-person games ; strategies
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    Topics: Biology , Mathematics
    Notes: Abstract This note contains a generalization of the definition of an evolutionary stable strategy and of the corresponding game dynamics from 2-person to n-person games. This broader framework also allows modelling of several interacting populations or of populations containing different “types” of individuals, for example males and females.
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  • 189
    ISSN: 1432-1416
    Keywords: Evolution ; quantitative inheritance ; random matrix theory ; morphological integration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Abstract A quantitative genetic model of “random pleiotropy” is introduced as reference model for detecting the kind and degree of organization in quantitative genetic variation. In this model the genetic dispersion matrix takes the form of G = BB T, where B is a general, real, Gaussian random matrix. The eigenvalue density of the corresponding ensemble of random matrices (ℰG) is considered. The first two moments are derived for variance-covariance matrices G as well as for correlation matrices R, and an approximate expression of the density function is given. The eigenvalue distribution of all empirical correlation matrices deviates from that of a random pleiotropy model by a very large leading eigenvalue associated with a “size factor”. However the frequency-distribution of the remaining eigenvalues shows only minor deviations in mammalian skeletal data. A prevalence of intermediate eigenvalues in insect data may be caused by the inclusion of many functionally unrelated characters. Hence two kinds of deviations from random organization have been found: a “mammal like” and an “insect like” organization. It is concluded that functionally related characters are on the average more tightly correlated than by chance (= “mammal like” organization), while functionally unrelated characters appear to be less correlated than by random pleiotropy (“insect like” organization).
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    Theoretical and applied genetics 68 (1984), S. 187-192 
    ISSN: 1432-2242
    Keywords: Vicia ; nuclear DNA ; Evolution ; Base sequence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The composition of nuclear DNA in 3 Vicia species are compared. The species V. eriocarpa, V. johannis and V. melanops are from three separate subgeneric sections of Vicia and show a fourfold variation in their amounts of nuclear DNA. DNA melting experiments, buoyant density gradient analysis and Cot reassociation experiments show that the quantitiative change in nuclear DNA between the three species is achieved by changes in the amounts of both repetitive and nonrepetitive DNA sequences. It is suggested that while the increase in the repetitive fraction is achieved by the proliferation of repetitive base sequences the increase in the nonrepetitive fraction is due to the steady accretion of highly diverged base sequences resulting from mutations, deletions, insertions and base sequence rearrangements among families of repetitive sequences.
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    Cell & tissue research 235 (1984), S. 657-661 
    ISSN: 1432-0878
    Keywords: Evolution ; Endocrine pancreas ; Regulatory peptides ; Snakes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The pancreas from eleven species of snakes representing both advanced and primitive families has been investigated for the presence of eleven regulatory peptides reported to occur in the mammalian endocrine pancreas. Of the eleven peptides studied, insulin, pancreatic glucagon and somatostatin were present in endocrine cells within the islets of all the species investigated. The neuropeptide, vasoactive intestinal polypeptide, was located within nerve terminals innervating the islets in the Boidinae, Colubrinae, Elaphidae and Crotalidae but absent from the Natricinae investigated. No immunoreactivity was demonstrable with the antisera to substance P, met-enkephalin, C-terminal gastrin, bombesin, glicentin and gastric inhibitory polypeptide. Pancreatic polypeptide-like immunoreactivity was demonstrable only in the boid snakes and exclusively stained by a C-terminal specific antiserum.
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    Plant systematics and evolution 144 (1984), S. 209-220 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Poaceae ; Triticum ; Elytrigia ; wheat ; Evolution ; genome ; karyotype
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The lengths of the A, B, and D genomes of common wheat,Triticum aestivum, were measured from the karyotype. Relative to the B genome, standardized as length 1.000, the lengths of the A and D genomes were 0.835 and 0.722, respectively. The lengths of the chromosome arms in the A and D genomes were then multiplied by the appropriate constants so that the total lengths of each genome also equalled 1.000. These calculations revealed that homoeologous chromosomes in wheat, with a few exceptions, have similar sizes and arm ratios. The arm lengths of the three homoeologues in each homoeologous group were then averaged. These average chromosomes turned out to be remarkably similar, in size and arm ratio, to their homoeologues in the E genome ofElytrigia elongata. This evidence and data on cross-compatibility and morphological characteristics suggested that the genusTriticum is a result of adaptive radiation from the perennial genusElytrigia, specifically from the complex of species possessing the E genome or one closely related to it.
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    Plant systematics and evolution 145 (1984), S. 203-222 
    ISSN: 1615-6110
    Keywords: Fabaceae ; Leguminosae ; Medicago ciliaris ; Medicago intertexta ; Medicago muricoleptis ; Medicago granadensis ; Evolution ; chromosomes ; Pleistocene glaciations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Karyotype and external morphological analyses were conducted onMedicago ciliaris, M. intertexta, M. muricoleptis andM. granadensis which comprise theIntertextae section of the genusMedicago. All species were found to have 2n = 16 chromosomes (= 2 ×), including one pair of satellite chromosomes in each respective complement. Karyotypic evolution in theIntertextae involves changes in absolute chromosome size and in centromeric and relative size symmetry. Numerical taxonomic analyses were conducted independently on 17 karyotypic features and on 16 features of external morphology. The results of the two sets of analyses proved comparable, withM. ciliaris andM. intertexta forming a fairly close pair, and the remaining two species appearing to have more distant relationships to each other and to the first pair. These observations are consistent with the infertility relationships and chorologies of the species. It is suggested thatM. muricoleptis andM. granadensis are derived from theM. ciliaris/intertexta species complex withM. granadensis arising fromM. muricoleptis, or these two species independently evolving from a common species complex. Chromosomal and numerical analyses suggest thatM. ciliaris is the most primitive andM. granadensis the most derived species of theIntertextae.
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    Plant and soil 82 (1984), S. 337-357 
    ISSN: 1573-5036
    Keywords: Evolution ; Grain legumes ; Induced mutations ; Mutation breeding ; Symbiotic nitrogen fixation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Grain legumes are an important group of crop plants. They provide an essential source of protein food for many developing countries, but their production has gone down in favour of more profitable crops like cereals. Therefore, genetic improvement of grain legumes is urgently needed. The primary aim of grain legume breeding must be the increase of production through adaptation to more advanced cropping schemes and reduction of crop losses. Symbiotic nitrogen fixation as developed by natural evolution does not always seem to be compatible with the needed substantial increase in yield: It is not supplying sufficient nitrogen and supplementation by fertilizer is rather uneconomic. By genetic manipulation of the plant's regulatory system nitrogen fixation may become more effective and tolerant to high soil nitrogen levels. Through a number of mutation breeding projects in different countries involving all important grain legume species it has been proven that mutation induction is a good tool for supplementing the genetic variation available from natural evolution and from selection by man. High-yielding cultivars have been developed from induced mutants, which eventually also possess a more efficient nitrogen fixation capacity.
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  • 195
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    Environmental biology of fishes 10 (1984), S. 3-14 
    ISSN: 1573-5133
    Keywords: Mormyriforms ; Gymnotiforms ; Communication ; Spawning cues ; Circannual cycles ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
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  • 196
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    Environmental biology of fishes 10 (1984), S. 111-116 
    ISSN: 1573-5133
    Keywords: Branchial canopy ; Evolution ; Interbranchial septum ; Isurus oxyrinchus ; Passive gill ventilation ; Prionace glauca ; Ram gill ventilation ; Secondary lamellae ; Sphyrna zygaena
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Gill filaments of one highly active and two less active shark species exhibit a conservative morphological scheme including such features as branchial canopies, marginal lamellar projections, and enlarged, discrete outer marginal lamellar channels and lateral lamellar sinuses. The specific spatial orientation of the secondary lamellae respective to one another, the gill filaments, and the interbranchial septa create what appears as one-way interfilament water channels, suggesting the presence of an efficient branchial countercurrent system. It is proposed that the fortified structure of shark gills allows many shark species to ventilate passively without having evolved gill filament modifications as apparently did some highly active teleosts. This in turn may have expedited the evolution of lamnid shark species through pre-adaptation to a swift oceanic lifestyle.
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  • 197
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    Journal of molecular evolution 19 (1983), S. 203-213 
    ISSN: 1432-1432
    Keywords: Evolution ; Phylogenetic distribution ; Repetitive-dispersed DNAs ; Speciation ; Transposons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have examined the phylogenetic distribution of a spectrum ofDrosophila repetitive-dispersed DNAs ranging from structurally complex transposable elements to scrambled middle repetitive sequences. Our data suggest that unlike typical “genes” these DNAs are unstable components of the drosophilid genome. The unusual behavior of these repetitive-dispersed DNAs raises the possibility that this type of sequence may have an important role in the evolution of the family Drosophilidae.
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  • 198
    ISSN: 1432-1432
    Keywords: Microbial phylogeny ; Evolution ; Aromatic biosynthesis ; Regulatory enzymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Pseudomonad bacterial are a phylogenetically diverse assemblage of species named within contemporary genera that includePseudomonas, Xanthomonas andAlcaligenes. Thus far, five distinct rRNA homology groups (Groups I through V) have been established by oligonucleotide cataloging and by rRNA/DNA hybridization. A pattern of enzymic features of aromatic amino acid biosynthesis (enzymological patterning) is conserved at the level of rRNA homology, five distinct and unambiguous patterns therefore existing in correspondence with the rRNA homology groups. We sorted 87 pseudomonad strains into Groups (and Subgroups) by aromatic pathway patterning. The reliability of this methodology was tested in a blind study using coded cultures of diverse pseudomonad organisms provided by American Type Culture Collection. Fourteen of 14 correct assignments were made at the Group level (the level of rRNA homology), and 12 of 14 correct assignments were made at the finer-tuned Subgroup levels. Many strains of unknown rRNA-homology affiliation had been placed into tentative rRNA groupings based upon enzymological patterning. Positive confirmation of such strains as members of the predicted rRNA homology groups was demonstrated by DNA/rRNA hybridization in nearly every case. It seems clear that the combination of these molecular approaches will make it feasible to deduce the evolution of biochemical-pathway construction and regulation in parallel with the emerging phylogenies of microbes housing these pathways.
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  • 199
    ISSN: 1432-1432
    Keywords: mtDNA ; Gene mapping ; Evolution ; Yeasts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Mapping of sequences specifying the large and small ribosomal RNAs and six polypeptides in the circular 23.7 kbp mitochondrial DNA ofSaccharomyces exiguus has shown that these genes have the same orientation and that a 5 gene cluster is common to this DNA and the 18.9 kbp mtDNA fromTorulopsis glabrata. Included in the preserved region are juxtaposed sequences specifying ATPase subunits 6 and 9 which have the same order and orientation as analogous genes in theEscherichia coli unc operon. The above data, together with knowledge that these two sequences are dispersed in larger yeast mtDNAs, leads us to suggest that larger forms are derived from a smaller ancestral molecule that would have had some resemblance to the mtDNAs ofS. exiguus andT. glabrata.
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  • 200
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    Journal of molecular evolution 19 (1983), S. 342-345 
    ISSN: 1432-1432
    Keywords: mtDNA ; Gene mapping ; Evolution ; Yeasts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Analysis of gene order and orientation in the circular 18.9 kbp mitochondrial DNA molecule ofTorulopsis glabrata has shown that the eight large genic sequences have the same orientation and that a five gene cluster which runs — cytochrome b, cytochrome oxidase subunit 1, ATPase subunits 6 and 9 and cytochrome oxidase subunit 2 — is common to this DNA andSaccharomyces exiguus mtDNA (see accompanying paper).
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