But what is available provides important context for the Population Y debate.

Ancient genomes from Siberia dating to the period relevant to American settlement — roughly 20,000 to 40,000 years before present — show a complex genetic landscape.

Different ancient Siberian individuals show different combinations of ancestral components, including components related to East Asian populations, components related to western Eurasian populations (sometimes called “Ancient North Eurasian” ancestry), and in some cases components that are more distantly related to the populations that eventually moved south toward Australia and Melanesia.

This ancient Siberian diversity is relevant to Population Y because the ancestral Native American population is thought to have formed in the Beringian region from a mixture of different Asian source populations — and if those source populations included groups with more “Australasian-related” ancestry from the deep past, then the founding Native American population would have contained some proportion of that ancestry.