Short answers, pulled from the story.
Ancient Beringian is a human genetic lineage identified from the genome of an infant, known as USR1, found at the Upward Sun River site and dated to 11,500 years ago. It diverged from the Ancestral Native American lineage about 20,000 years ago.
The remains that revealed the Ancient Beringian lineage, two female infants, were excavated in 2013 at the Upward Sun River site. The genomic findings were published in January 2018 in the journal Nature.
No. The Ancient Beringian lineage is extinct and is not found among modern indigenous populations in Alaska. A 2018 study suggests it was replaced or absorbed by a back-migration of the North Native American lineage.
The nuclear DNA of the USR1 infant was analyzed at the Centre for Geogenetics, part of the University of Copenhagen's Natural History Museum of Denmark.
The Ancestral Native American lineage formed between 20,000 and 25,000 years ago from a mixture of roughly 65 percent East Asian ancestry and 35 percent Ancient North Eurasian ancestry. This is consistent with a model of peopling the Americas via Beringia during the Last Glacial Maximum.
Modern Athabaskan populations descend from an admixture of the North Native American back-migration into Alaska and a separate Paleo-Siberian lineage, a blend the research dates to before about 2,500 years ago.