A sexually prolific group of Northern Eurasians roamed the ancient world, mating with everyone from the ancestors of Native Americans to Eastern Europeans, say Harvard researchers who suggest the findings should expand existing views of how modern man came to be.
The research, released today by the journal Nature, upends existing scientific wisdom that modern Europeans are the result of hunter-gatherers and indigenous farmers who bred exclusively among themselves, according to researchers at Harvard Medical School in Boston and Germany’s University of Tubingen.
The report suggests a third group, Eurasians who swept in from an area now part of northern Russia, spurred demographic changes across two continents, the scientists said. The study compared DNA in two Eurasian skeletons from that ancient period with DNA gathered from past archaeological finds in a range of countries, as well as DNA from 2,300 present-day people.
“A lot of archaeologists were skeptical there might have been major population movements” from the east, said David Reich, a Harvard genetics professor and co-author of the study. “That’s not true obviously.”
The finding comes after archaeologists searching in Siberia found the bones of two North Eurasians, according to the journal report. The genetic comparisons tied the Eurasians to almost every European group of people, as well as populations between Western Europe and Asia.
They also demystified the link between Europeans and Native Americans on the American continent by finding that the Eurasians contributed to the DNA of those who crossed the Bering Strait some 15,000 years ago.
Still, the study raises some questions. The scientists said they don’t know when the North Eurasians moved into the rest of Europe, or understand why they mated with the people they encountered as frequently as they did.
According to Reich, the Eurasians’ romantic pursuits were unusual. Historically, when a more technologically advanced group moved into a new area, they tended to displace the existing population instead of mixing with it.
“The obvious thing we want to work on next is to try to understand when this third ancestry group came into Europe and we’ll do more DNA sequencing from later in Europe,” Reich said. “It’s important for understanding the historical trends of human origins.”