I take it these are the people that "native American" Indians exterminated when when they came here.
Their ancestors. The genetics timeline matches up. Up till now the explanation for the different genetics of Native Americans was explained by the Berengia Standstill hypothesis. This find blows that up.
“In this scenario, the Asian emigrants probably reached Beringia before the full brunt of the Last Glacial Maximum, a period of glaciers and fierce cold that lasted from roughly 27,000–19,000 years ago. Once in Beringia, the emigrants could go no further, thanks to the ice sheets blocking the door to the rest of the Americas. Tamm’s group hypothesized that people were isolated in Beringia for up to 15,000 years until they could venture into the unknown lands to the east.” https://www.pnas.org/content/114/22/5554