The Insight Show Notes — Season 2, Episode 7: the genetics of Native Americans
This week on The Insight (Apple Podcasts and Stitcher) Razib Khan and Spencer Wells discuss the genetics and history of Native Americans, from the icy shores of the Arctic and to the frigid windswept plains of Patagonia, and all places in between. A 15,000 years story of migration and settlement.
There was a lot of talk about Beringia. This is a region between Alaska and Siberia which is now under the ocean. But during the Last Glacial Maximum ~20,000 years ago when sea levels were lower it likely served as a refuge for Paleo-Siberians who retreated from other zones of northeast Asia. Once the climate warmed and the ice sheets opened up, about 15,000 years ago it seems that humans began to migrate southward.
A new preprint, The population history of northeastern Siberia since the Pleistocene, outlines the context of the emergence of the Beringian ancestors of modern Native Americans about 20,000 years ago. They were the fusion of two populations. One group was related to the people of modern East Asia, such as the Han Chinese. This group contributed about 60–70% of the ancestry to the Beringian population.
But the second population, sometimes termed “Ancient North Eurasians”, are very distantly related to the peoples of Europe. This group contributed to 30–40% of the ancestry to modern Native Americans, as well as 10–20% of the ancestry of Northern Europeans, and substantial fractions in parts of West and South Asia. See, 24,000-Year-Old Body Shows Kinship to Europeans and American Indians.
We alluded to the Beringian standstill hypothesis, that the Berengians were bottled up within their small corner of the world for many thousands of years. This is also connected to the small founding population of the New World.
Spencer discussed that haplogroup Q, the paternal lineage common in the New World, has a wide distribution in Eurasia. This could be the impact of the Ancient North Eurasians:
There was an extensive survey of the archaeology of the New World, and the Clovis First hypothesis. The Monte Verde site was mentioned as one of the primary ways in which Clovis First was refuted. Finally, we mentioned a paper in Nature that might push the occupation as far back as 130,000 years! (though most archaeologists dismiss it).
There was some reference to the Greenberg model of the classification of Amerind languages, as well as the Dené–Yeniseian family.
Much of the middle of the podcast focused on two papers that came out this week that filled in many details of the populating of the New World, one in Cell, and another in Science.
We talked about a 2015 result that indicated an Australasian population contributed some ancestry to people in the Amazon.
Interested in learning where your ancestors came from? Check out Regional Ancestry by Insitome to discover various regional migration stories and more!
