The interbreeding with the second Denisovan population apparently happened in mainland Asia, perhaps in the high-altitude environments where Denisovans with high-altitude adaptations are most likely to have lived.

The Xiahe mandible from Tibet — possibly Denisovan, though identified through protein rather than DNA analysis — and the Denisovan-derived EPAS1 high-altitude adaptation in Tibetan populations may represent the physical and functional legacy of the second Denisovan population.

If so, these Denisovans were high-altitude specialists whose genetic adaptations to thin air were so effective that they were incorporated into the modern human population that inherited them.

For Denny, this distinction is relevant because it places her — and the Denisovans of Denisova Cave — in a specific geographic and population context that is distinct from the full range of Denisovan diversity.