December 31, 2006

Convergent skin color evolution in Caucasoids and Mongoloids

MBE Advance Access published online on December 20, 2006

Genetic Evidence for the Convergent Evolution of Light Skin in Europeans and East Asians

Heather L. Norton et al.

Human skin pigmentation shows a strong positive correlation with ultraviolet radiation (UVR) intensity, suggesting that variation in skin color is, at least partially, due to adaptation via natural selection. We investigated the evolution of pigmentation variation by testing for the presence of positive directional selection in six pigmentation genes using an empirical FST approach, through an examination of global diversity patterns of these genes in the CEPH-Diversity Panel, and by exploring signatures of selection in data from the International HapMap project. Additionally, we demonstrated a role for MATP in determining normal skin pigmentation variation using admixture mapping methods. Taken together (with the results of previous admixture mapping studies), these results point to the importance of several genes in shaping the pigmentation phenotype and a complex evolutionary history involving strong selection. Polymorphisms in two genes, ASIP and OCA2, may play a shared role in shaping light and dark pigmentation across the globe while SLC24A5, MATP, and TYR have a predominant role in the evolution of light skin in Europeans but not in East Asians. These findings support a case for the recent convergent evolution of a lighter pigmentation phenotype in Europeans and East Asians.


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