Northeastern Siberia hosted migrations of three consecutive ancient populations that created a genetic framework for Siberians and Native Americans today, scientists say.
While each incoming population largely replaced people already living there, mating between newcomers and old-timers also occurred, conclude evolutionary geneticist Martin Sikora of the University of Copenhagen and colleagues. These findings provide a closer look at how complex interactions among different groups of people in Asia led to the colonization of North America.
Sikora’s group analyzed DNA extracted from the remains of 34 people buried in northeastern Siberia, northern East Asia and southwestern Finland between about 31,600 and 600 years ago. Comparisons were made with DNA previously obtained from ancient and modern individuals across Eurasia and North America.
Teeth from two children unearthed at Russia’s 31,600-year-old Yana Rhinoceros Horn site yielded DNA representing a previously unknown population that the team calls Ancient North Siberians. Those people migrated from western Eurasia to Siberia around 38,000 years ago, quickly adapting to the region’s especially frigid Ice Age conditions, the team reports online June 5 in Nature.
Some Ancient North Siberians journeyed onto the Bering land bridge that connected Asia to North America around 30,000 years ago. Mating with East Asians who had also moved to the land bridge produced a genetically distinct population, dubbed Ancient Palaeo-Siberians by the researchers. As the climate became milder after 20,000 years ago, some of the Ancient Palaeo-Siberian population returned to northeastern Siberia, replacing the Yana crowd.
Other Ancient Palaeo-Siberians trekked from the land bridge into North America, the researchers say. Some of this group’s descendants returned to Siberia by sea between 11,000 and 4,000 years ago, after rising waters had submerged the bridge. Many Siberians today have descended from that population, referred to as Neo-Siberians by the scientists.
A nearly 10,000-year-old Siberian man’s DNA enabled the researchers to identify genetic links between Ancient Palaeo-Siberians and present-day native communities in both modern Siberia and North America.