Genetic evidence for two founding populations of the Americas

Abstract

Genetic studies have been consistent with a single common origin of Native American groups from Central and South America1-4. However, some morphological studies have suggested a more complex picture, whereby the northeast Asian affinities of present-day Native Americans contrast with a distinctive morphology seen in some of the earliest American skeletons, which share traits with present-day Australasians (indigenous groups in Australia, Melanesia, and island southeast Asia)5-8. Here we analyze genome-wide data to show that some Amazonian Native Americans descend partly from a Native American founding population that carried ancestry more closely related to indigenous Australians, New Guineans and Andaman Islanders than to any present-day Eurasians or Native Americans. This signature is not present to the same extent or at all in present-day Northern and Central Americans or a ~12,600 year old Clovis genome, suggesting a more diverse set of founding populations of the Americas than previously accepted.

Detecting Polygenic Adaptation in Admixture Graphs

“…The signal seems only very weakly present in some Siberian populations -like the Even and Nganasan -and some Native American populations -like the Mixe and Pima, and not present at all in other Native American populations -like the Surui, Quechua and Karitiana. This is perhaps explained by the complex demographic make-up of Siberian and Native American populations, and their divergent history from East Asians (Pugach et al 2016;Skoglund et al 2015;Raghavan et al 2015).…”

Deep History of East Asian Populations Revealed Through Genetic Analysis of the Ainu

“…Second, for populations outside East Asia and Siberia, we arbitrarily chose Ju_hoan_North and Mandenka for Africans, Sardinian and Basque for Europeans, Papuan for Oceania, and Karitiana and Surui for Native Americans. These populations represent major branches of human continental diversity and have been used as such representatives in many population genetic studies (Li et al 2008;Reich et al 2011;Keller et al 2012;Skoglund et al 2015). Last, we removed the She from the analysis because of its unstable position in the population trees generated by TreeMix (Pickrell and Pritchard 2012).…”

Ancient DNA and human history

“…Skoglund et al (47) analyzed a large SNP dataset that included 63 individuals from 21 present-day Native American populations and reached a conclusion similar to that of Raghavan et al (46), but one that differs somewhat. Skoglund et al (47) found that some but not all Native American populations contained a strong signal of Australo-Melanesian ancestry, especially among certain South American populations.…”

“…Skoglund et al (47) found that some but not all Native American populations contained a strong signal of Australo-Melanesian ancestry, especially among certain South American populations. Furthermore, they could reject the hypothesis that Native American populations were descended from a single randomly mixing population.…”