The Neanderthals Zlatý kůň’s ancestors interbred with were likely among the last populations of their kind, living in the face of an expanding modern human presence.

The presence of relatively long Neanderthal segments in Zlatý kůň’s genome, compared to other ancient individuals, is what allows researchers to use her genome to date the admixture event and, in turn, to estimate her own age.

It is a remarkable thing: the traces of ancient sex that resulted in viable offspring, encoded in the chemical structure of a woman’s DNA and preserved in a cave for 45,000 years, can tell us when she lived.

The Neanderthal component of her genome is small — as in all modern humans, a few percent at most, likely less.