Genetic analysis of two infants buried at an Alaskan campsite 11,500 years ago revealed that the DNA of the babies were the northernmost members of two separate Native American lineages, a new Proceedings of the National Academy of Sciences study published Monday reported.
The discovery of the infants, who had separate mothers, helps support the so-called “Beringian standstill model” which suggests that Native Americans originally descended from a people that migrated from Asia to Beringia (the land bridge that once linked Siberia and Alaska), where they spent up 10,000 years before continuing on into the Americas starting 15,000 years ago.
“These infants are the earliest human remains in northern North America,” University of Utah anthropology professor Dennis O’Rourke, senior author of the paper, said in a statement, “and they carry distinctly Native American lineages. We see diversity that is not present in modern Native American populations of the north and we see it at a fairly early date.”
He added that the discovery provided “evidence there was substantial genetic variation in the Beringian population before any of them moved south,” and “supports the Beringian standstill theory in that if [the infants] represent a population that descended from the earlier Beringian population, it helps confirm the extent of genetic diversity in that source population.”
All five major Native American lineages now traced to Beringia
The fact that these distinctly Native American lineages have never been found anywhere in Asia, (not even in Siberia) indicates that there must have been a prolonged period where the group was isolated from their Asian ancestors, O’Rourke said. He believes this took place in Beringia.
One of the babies was between six and 12 weeks old, while the other was either a 30-week fetus or a stillborn infant. They were part of human remains found at eight North American sites older than 8,000 years from which scientists were able to obtain mitochondrial DNA—genes passed on exclusively by mothers. These rare buried infants were the northernmost of them all.
In their work at these eight sites, the researchers were able to find “all five of the major lineages of Native Americans,” said Justin Tackney, first author of the study and a anthropology doctoral student at the University of Utah. “That indicates that all were present in the early population in Beringia that gave rise to all modern Native Americans.”
“Studying the DNA of ancient individuals is important in researching how the Western Hemisphere was populated,” he added. “Studying the genetics of these infants who died 11,500 years ago in what is now central Alaska helps answer questions of who these people were and how they are related to modern native populations.”
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Feature Image: Ben Potter, University of Alaska Fairbanks
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