Photo credit: Eric S. Carlson in collaboration with Ben A. Potter

The genome of a baby girl buried 11,500 years ago in Alaska has revealed a new discovered group of ancient people. 

The group has been named, “ancient Beringias,” and appears to have split off from the founding population of Native Americans about 20,000 years ago. 

Researchers from the University of Alaska Fairbanks and the University of Copenhagen have helped fill in more details about the genetic origins of Native Americans. The study has been published in the journal Nature

Joshua Schraiber, a population geneticist at Temple University, commented, “If you could ask for ancient DNA for Christmas, this is what you would ask for. It gives you a much better window into population structure back then.”

Using evolutionary models, the researchers were able to show that the ancestors of the first Native Americans started to emerge as a distinct population about 35,000 years ago, most probably in north-eat Asia. 

Connie Mulligan, an anthropologist at the University of Florida, believes the findings point to a single migration of people from Asia to the New World, but said other questions remained. 

“How did people move so quickly to the southernmost point of South America and settle two continents that span a huge climatic and geographic range?” she said. 

The study involves the DNA extracted from one of the babies that archaelogists led by Ben Potter unexpectedly discovered at a site in Central Alaska, called Upward Sun River. 

From their bones, the researchers estimated that one of the infants in the burial pit had been about six weeks old when it passed away, and the other was likely stillborn. “We’re very lucky to have these preserved,” Potter explained. “We’re treating them very respectfully and letting them provide a window into their prehistory, and past, and lifeways in ways that are unparalleled.”

Eske Willerslev, an evolutionary geneticist at the University of Copenhagen and her team recovered the girl’s DNA from a dense part of her skull known as the petrous bone. 

She compared the genetic makeup of the baby, named Xach’itee’aanenh t’eede gaay or “sunrise child-girl” by the local community, with genomes from other ancient and modern people. 

They discovered that nearly half of the girl’s DNA came from the ancient north Eurasians who lived in what is now Siberia. The rest of her genetic makeup was a roughly even mix of DNA now carried by the northern and southern Native Americans. 

Geneticist at Harvard University, David Reich, said that the work boosted the case for a single migration into Alaska, but hasn’t ruled out alternatives involving multiple waves of migration. 

He went on to add that he was unconvinced that the ancient Beringian group split from the ancestors of other Native Americans 20,000 years ago, because even small errors in scientists’ data can lead to radically different split times for evolutionary lineages. 

“While the 19,000-21,000 year date would have important implications if true and may very well be right, I am not convinced that there is compelling evidence that the initial split date is that old,” he concluded. 

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