Ancient DNA preservation in underwater environments is not the same as preservation in dry cave environments.

Water facilitates the bacterial degradation of DNA and the chemical processes that break DNA strands into fragments.

Most underwater archaeological sites do not yield useful ancient DNA from human remains.

The expectation, when researchers first began planning the genetic analysis of Naia’s remains, was that the DNA might be too degraded to sequence or might yield such limited data that the results would be inconclusive.

But the specific chemistry of the Hoyo Negro cave water had been unusually kind to the organic material in Naia’s bones.