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Ancient DNA fine-tunes understanding of peopling of the Americas

A new study offers a fine-tuned chronology of the peopling of the New World and sheds light on the genetic lineage of Native Americans. The geographic isolation of the Americas delayed settlement there until the end of the Pleistocene, roughly ten to twenty thousand years ago, and despite much research, the specific time, place and route of entry of early people into the Americas remains uncertain.

A better understanding of the size, number, and speed of the first migratory waves could help resolve controversial issues such as the origins of people on the continent before the Clovis, the first widespread, archaeologically recognized culture in North America. Here, Bastien Llamas et al. used archaeological evidence to provide further insight. They sequenced 92 whole mitochondrial genomes from pre-Columbian South American skeletons, generating data that indic ate a small population – one previously isolated in eastern Beringia – entered the Americas via a costal route around 16,000 years ago.

This matrilineal look at the genetic diversity of early peoples, along with reconstructions of demographic history and population modeling, further narrows the window of arrival of people in the Americas. The results also hint that European contact may have played a role, among other factors, in reducing the overall genetic diversity in Native Americans to the low levels observed today.

Article: Ancient mitochondrial DNA provides high-resolution time scale of the peopling of the Americas, Bastien Llamas et al., Science Advances, doi: 10.1126/sciadv.1501385, published 1 April 2016.