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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of mathematical biology 10 (1980), S. 155-166 
    ISSN: 1432-1416
    Keywords: Heterozygosity ; Number of alleles ; Mutation and selection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Summary One of the major goals of population genetics is to discover the nature and amount of genetic variation in natural populations. Various measures, including the population heterozygosity at any locus and the number of alleles extant at the locus, have been used for this purpose. An important task of theoretical population genetics is thus to provide expressions for the mean values of these two quantities (when calculated from a sample of genes) for various models of selection, mutation and random drift. This aim has been achieved for the selectively neutral case, where all alleles at the locus are assumed to be selectively equivalent. It is, however, generally agreed that classes of (evolutionarily unimportant) selectively deleterious alleles exist, so that the neutral theory calculations should be extended to cover this case. This has previously been done only for extremely weak selection. In this paper we obtain, via the confluent hypergeometric function and three allied functions, concise and simple exact and approximate formulae for the means of the above measures of population variation for arbitrary selective values. These all derive from the allelic “frequency spectrum”, which is of independent interest in assessing likely models of population variation.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular evolution 23 (1986), S. 61-75 
    ISSN: 1432-1432
    Keywords: Duplicate genes ; Accelerated evolution ; Processed pseudogenes ; Age of pseudogenes ; Phylogenetic relationships
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A statistical analysis of the nucleotide sequences of cytochrome c genes from four species of animals and two of yeast and of cytochrome c pseudogenes from rat, mouse, and human was conducted. It was estimated that animals and yeast diverged 1.2 billion years ago, that the two duplicated genes DC3 and DC4 inDrosophila diverged 520 million years ago, and that the two duplicated genes Iso-1 and Iso-2 in the yeastSaccharomyces cerevisiae diverged 200 million years ago. DC3 is expressed at a low level and has evolved 3 times faster than DC4. This observation supports the neutralist view that relaxation of functional constraints is a more likely cause of accelerated evolution following gene duplication than is advantageous mutation. All the rodent pseudogenes examined appear to be processed pseudogenes derived directly from the functional genes, and most of them apparently arose after the mosue-rat split. No event of gene conversion could be detected between any pair of the rodent pseudogenes. Our analysis suggests that the human cytochrome c gene has evolved at a rate comparable to the average rate for pseudogenes, whereas some human cytochrome c pseudogenes have evolved at an exceptionally low rate.
    Type of Medium: Electronic Resource
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