DNA polymorphism in lycopersicon and crossing-over per physical length - PubMed (original) (raw)

DNA polymorphism in lycopersicon and crossing-over per physical length

W Stephan et al. Genetics. 1998 Dec.

Abstract

Surveys in Drosophila have consistently found reduced levels of DNA sequence polymorphism in genomic regions experiencing low crossing-over per physical length, while these same regions exhibit normal amounts of interspecific divergence. Here we show that for 36 loci across the genomes of eight Lycopersicon species, naturally occurring DNA polymorphism (scaled by locus-specific divergence between species) is positively correlated with the density of crossing-over per physical length. Large between-species differences in the amount of DNA sequence polymorphism reflect breeding systems: selfing species show much less within-species polymorphism than outcrossing species. The strongest association of expected heterozygosity with crossing-over is found in species with intermediate levels of average nucleotide diversity. All of these observations appear to be in qualitative agreement with the hitchhiking effects caused by the fixation of advantageous mutations and/or "background selection" against deleterious mutations.

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References

    1. Biochem Genet. 1990 Oct;28(9-10):543-52 - PubMed
    1. Theor Popul Biol. 1975 Apr;7(2):256-76 - PubMed
    1. Genet Res. 1996 Oct;68(2):131-49 - PubMed
    1. Genet Res. 1974 Feb;23(1):23-35 - PubMed
    1. Genetics. 1991 Dec;129(4):1111-7 - PubMed

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