Who We Are and How We Got Here

摘抄——p500

There was a problem, though, which is that the analysis did not account for the 3 to 6 percent of ancestry that Australians inherited from archaic Denisovans.19 Because Denisovans were so divergent from modern humans, mixture from them could cause Europeans to share more mutations with Chinese than with Australian Aborigines. Indeed, this explained the findings. My laboratory showed that after accounting for Denisovan mixture, Europeans do not share more mutations with Chinese than with Australians, and so Chinese and Australians derive almost all their ancestry from a homogeneous population whose ancestors separated earlier from the ancestors of Europeans.20 This revealed that a series of major population splits in the history of non-Africans occurred in an exceptionally short time span—beginning with the separation of the lineages leading to West Eurasians and East Eurasians, and ending with the split of the ancestors of Australian Aborigines from the ancestors of many mainland East Eurasians. These population splits all occurred after the time when Neanderthals interbred with the ancestors of non-Africans fifty-four to forty-nine thousand years ago, and before the time when Denisovans and the ancestors of Australians mixed, genetically estimated to be 12 percent more recent than the Neanderthal/modern human admixture, that is, forty-nine to forty-four thousand years ago.21

摘录——p519

Our analysis supported a model of population history in which the modern human ancestry of the great majority of mainland East Asians living today derives largely from mixtures—in different proportions—of two lineages that separated very anciently. Members of these two lineages spread in all directions, and their mixture with each other and with some of the populations they encountered transformed the human landscape of East Asia.