University of New York at Oneonta. Skin color is heavily correlated with latitude as well as race, but clearly does not follow the pattern of the neutral genes. Henry Harpending and Alan Rogers suggest that "other visible traits that most humans notice are more like skin color than they are like neutral traits"—in other words that most of the physical characteristics on which people judge a person's race are likely to be selected, just as would be expected if sexual selection has been the major force differentiating the human population.244 It is a few selected genes, not the many neutral ones, that may account for the differences between continental races. Substantial evidence for this idea has now emerged from a genomewide survey by Jonathan Pritchard of the University of Chicago. Devising a test to identify genes under recent selective pressure, he found roughly 200 such genes in Africans, in East Asians, and in Europeans. Each race's set of selected genes overlapped very little with those of other races, just as would be expected if the populations on each continent had adapted independently to evolutionary pressures._
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