The two branches appear to have diverged relatively early in the history of the post-Beringian expansion — possibly before the spread of Clovis technology, and possibly before the main southward expansion had reached its greatest geographic extent.

The northern branch is represented, in the ancient genomic record, by populations ancestral to many of the Indigenous peoples of the Arctic, Subarctic, and northern portions of the continent.

The southern branch is represented by the Anzick-1 genome from Montana — the Clovis-period child whose genome showed a stronger affinity with populations from Central and South America than with those from northern North America.

The USR1 genome — the Ancient Beringian lineage — sits outside this north-south split, representing a divergence that preceded the split between northern and southern branches.