April 23, 2007

Recent adaptive evolution in the human genome

PLoS Genetics (online early)

Localizing recent adaptive evolution in the human genome

Scott Williamson et al.

Identifying genomic locations that have experienced selective sweeps is an important first step toward understanding the molecular basis of adaptive evolution. Using statistical methods that account for the confounding effects of population demography, recombination rate variation, and SNP ascertainment, while also providing fine-scale estimates of the position of the selected site, we analyze a genomic data set of 1.2 million human SNPs genotyped in African-American, European-American, and Chinese samples. We identify 101 regions of the human genome with very strong evidence (P<10-5) of a recent selective sweep and where our estimate of the position of the selective sweep falls within 100 kb of a known gene. Within these regions, genes of biological interest include genes in pigmentation pathways, components of the dystrophin protein complex, clusters of olfactory receptors, genes involved in nervous system development and function, immune system genes, and heat shock genes. We also observe consistent evidence of selective sweeps in centromeric regions. In general we find that recent adaptation is strikingly pervasive in the human genome, with as much as 10% of the genome affected by linkage to a selective sweep.


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