Lineage separation· Where Sapiens lives
The founding population of the Americas separates
37.5 ka
A single founding population parts from East Asians, many thousands of years before anyone crosses into the Americas. Every Indigenous American lineage sequenced so far descends from it.
What the evidence shows
The estimate comes from a genome sequenced to seventeenfold coverage: an infant buried at Upward Sun River, in Alaska, some 11,500 years ago, who turns out to belong to no known branch of Native American ancestry but to sit below them all. Modelling that genome against the others gives a split from East Asians at 36,000 years, plus or minus 1,500, with gene flow continuing until about 25,000. The lineage then spent millennia apart without moving on, which is what the Beringian standstill describes. Ancient Beringians branched off between 22,000 and 18,100 years ago, and the northern and southern branches from which all later Native Americans descend parted between 17,500 and 14,600.
Dating & uncertainty
Moreno-Mayar and colleagues date this split to 36,000 years ago give or take 1,500, with gene flow continuing until about 25,000. Y-chromosome and mitochondrial work dates the effective separation to 25,000 years ago or later. The two need not conflict: one dates when the lineages began to part, the other when they stopped exchanging.