The Ancient Girl Whose DNA Revealed Her Parents Were Two Different Human Species

Denny is extraordinary partly because she is the only first-generation hybrid between two ancient human species ever found.

But she is almost certainly not the only one that ever existed.

The genetic evidence for Neanderthal-Denisovan interbreeding — the small signals in both Neanderthal and Denisovan genomes that suggest gene flow in both directions between the groups — implies that such interbreeding happened more than once.

Denny is the only case we have found.

But the sample of ancient individuals from which we have genomic data is tiny compared to the populations that actually lived in the ancient world.

Consider the numbers.