The results were consistently surprising.

Population histories that had seemed straightforward — the arrival of farming in Europe from the Near East, the origins of the steppe pastoralists who spread across Eurasia in the Bronze Age, the founding of the Americas — turned out, on examination by ancient genomics, to be far more complex, involving more population movements and more admixture events than had been recognized by archaeology and linguistics alone.

The Mal’ta case was one of the most dramatic of these surprises, because it revealed a previously uncharacterized ancestral component of a major contemporary population group.

The Ancient North Eurasian ancestry in Native American genomes had been a statistical residue in population genetic analyses — something that didn’t fit neatly into existing models — without a clear source population to point to.