DNA, unlike skull shape, is a more direct record of ancestry.

If Naia’s DNA was closely related to that of historical and modern Native American populations, it would argue strongly for continuity — for reading two.

If her DNA was closely related to some non-American population, or if it showed the signature of a completely separate founding lineage with no relationship to later Native Americans, it would argue for some version of reading one.

The challenge was extracting ancient DNA from bones that had spent twelve thousand years in a flooded cave.