A little girl who lived 11,500 years ago has helped scientists to understand the story of human migration to North America, and revealed a previously unknown Native American population.
In 2013 the remains of two infants were found at the Upward Sun River archaeological site in the Tanana River Basin in eastern Alaska. One appeared stillborn, while the other was six-to-12 weeks old when she died.
A team of researchers led by Eske Willerslev, who holds positions at the University of Cambridge, UK, and the University of Copenhagen in Denmark, has now conducted genetic analysis of the DNA of the older child, named Xach’itee’aanenh t’eede gay, or Sunrise Child-girl, by the local Native community. The results, published in Nature, are surprising.
It is generally accepted that the first humans came to North America via a land bridge across the Bering Strait exposed during the last Ice Age. That’s where the consensus ends. What is known is that this founding population gave rise to the two acknowledged branches of early Native Americans: the imaginatively named Northern and Southern groups.
Willerslev and his team have now shown that the genetic differences and similarities between Sunrise Child-girl and the populations of the Northern and Southern groups, as well as ancestral populations in East Asia and north-eastern Eurasia, indicate that people migrated to North America in a single wave.
“We were able to show that people probably entered Alaska before 20,000 years ago,” says Eske, “It’s the first time that we have had direct genomic evidence that all Native Americans can be traced back to one source population, via a single, founding migration event.”
Their findings also show that a third group, named “Ancient Beringians”, to which Sunrise Child-girl belonged, formed after the arrival of the founding population, but before the Northern and Southern groups split about 17,000 to 14,000 years ago. One of the researchers, José Victor Moreno-Mayar, says, “It looks as though this Ancient Beringian population was up there, in Alaska, from 20,000 years ago until 11,500 years ago, but they were already distinct from the wider Native American group.”
So, what happened to the Ancient Beringians? The researchers speculate that they eventually died out or were absorbed into the Northern group of Native Americans as they back-migrated north after the end of the last Ice Age. Nonetheless, Sunrise Child-girl and her people have shed welcome light on the story of the spread of humanity across the globe.
