Three Migrations into the Americas

An illuminating gene study has found that there were three distinct migrations from Siberia into the Americas, one early (from which most are descended) and two later, which produced three lineages corresponding to three language families:
(1) “First Americans” (i.e. all except:)
(2) Eskimo-Aleut speakers, and
(3) Na-Dene-speaking Chipewyan.
The latter two are more recent and more closely related to present-day East Asian populations. But there was mixture. 50% of Eskimo-Aleut DNA and 90% of Chipewyan comes from the “First Americans”. The southward expansion occurred along the coast while populations split off along the way. There was little gene flow among Native American groups, especially in South America. This suggests isolation and hostility. Finally, there was some back-migration to Siberia: two groups in NE Siberia (Naukan and coastal Chukchi) carry distinctive “First American” DNA from Eskimo-Aleut speakers.
DNA analysis is throwing considerable light on deep history.

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Filed under genetic history, human evolution

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