比较基因组学（宿兵）知识库

Human skin color diversity is considered an adaptation to environmental conditions such as UV radiation. Investigationsinto the genetic bases of such adaptation have identified a group of pigmentation genes contributing to skin colordiversity in African and non-African populations. Here, we present a population analysis of the pigmentation gene KITLGwith previously reported signal of Darwinian positive selection in both European and East Asian populations. Wedemonstrated that there had been recurrent selective events in the upstream and the downstream regions of KITLGin Eurasian populations. More importantly, besides the expected selection on the KITLG variants favoring light skin incoping with the weak UV radiation at high latitude, we observed a KITLG variant showing adaptation to winter tem-perature. In particular, compared with UV radiation, winter temperature showed a much stronger correlation with theprevalence of the presumably adaptive KITLG allele in Asian populations. This observation was further supported by thein vitro functional test at low temperature. Consequently, the pleiotropic effects of KITLG, that is, pigmentation andthermogenesis were both targeted by natural selection that acted on different KITLG sequence variants, contributing tothe adaptation of Eurasians to both UV radiation and winter temperature at high latitude areas.