The two children whose teeth yielded DNA were not closely related.

They were not brothers, or cousins.

Their genomes did not show the signatures of close inbreeding that would be expected if the Yana community were a small, isolated group marrying primarily within itself.

This is significant.

Small, isolated populations accumulate distinctive genetic signatures of inbreeding over time: increased homozygosity, runs of identical sequence inherited from common ancestors, patterns that are statistically distinguishable from the genomes of populations with more diverse ancestry.

The Yana children’s genomes did not show these signatures at levels that would suggest the community was dangerously small or isolated.