Origin: A Genetic History of the Americas

Hypothesized population migrations. Inset shows a phylogenetic tree and
time scale, with dotted arrow denoting gene flow.
We have recovered the genomes of the Ancient Beringians from an
archaeological site that tells us a story of another heartbreaking loss of
children. A little over 11,000 years ago, three children—a prenatal girl, a
three-month-old girl, and a three-year-old boy—were laid to rest under a
hearth inside their home in the Tanana River Valley in Alaska. Like the
Mal’ta boy, they were buried with care and provisions: hunting equipment
(including stone points and bifaces) and carved rods made out of antler. The
boy was cremated. Like the Mal’ta children, they were sprinkled with red
ochre.
We don’t know their names, but the peoples who live in the region today
—the Tanana Athabaskans of the Healy Lake tribe—call one of the girls
Xach’itee’aanenh T’eede Gaay (Sunrise Child-Girl), the other Yełkaanenh
T’eede Gaay (Dawn Twilight Child-Girl), and the boy Xaasaa Cheege
Ts’eniin (Upward Sun River Mouth Child). Their remains were discovered
by archaeologist Ben Potter in 2013, at a site known today as the Upward
Sun River, in the Tanana River Valley (15). The Healy Lake Traditional
Council and the Tanana Chiefs Conference (the broader regional
consortium of tribal leaders) were interested in knowing more about them
and so gave permission for archaeological and genetic research. “I would
like to learn everything we can about this individual (Xaasaa Cheege
Ts’eniin),” the Healy Lake Traditional Council’s First Chief Joann Polston
said in 2011. The Tanana Chiefs Conference President Jerry Isaac agreed:
“This find is especially important to us since it is in our area, but the
discovery is so rare that it is of interest for all humanity.” (16)
The mitochondrial genomes from both the girls and the complete
nuclear genome from Xach’itee’aanenh T’eede Gaay showed that they
belonged to a population that didn’t have any direct contemporary
descendants. Their ancestors had split off from the other Beringians
sometime between 22,000 and 18,000 years ago and remained in eastern
Beringia (Alaska) after the ice wall melted and the other groups moved
southward. We can tell from another genome recovered from the tooth of an
18-month-old child found at the Trail Creek Cave site on the Seward
Peninsula in Alaska (450 miles away) that this population wasn’t small, but