We document at least three major population turnovers in the region, with the earlier peoples showing very different ancestry than the later populations.”

Three major population turnovers.

This means that the people who lived in northeastern Siberia at one period were, to a significant degree, genetically different from the people who lived there in a subsequent period — not just because they were descended from different branches of the same ancestral population, but because different populations, with different origins and different demographic histories, had moved through the region, mixing with or replacing their predecessors.

This dynamism is surprising.