The encounter that produced Denisova 11 was not the meeting of modernity with archaism. It was archaic meeting archaic: two deeply diverged but closely related human populations whose lineages had separated approximately 400,000 years earlier, coming together in the Siberian mountains in the last interglacial period.
The last interglacial, roughly 130,000 to 115,000 years ago, was a warm period when much of Eurasia was forested and populated with large mammals. The period around 90,000 years ago falls in the early part of the subsequent glacial buildup—a time of environmental change and shifting habitats. Whether the environmental context was relevant to the Neanderthal-Denisovan encounter that produced Denisova 11 is unknown; it is possible that shifting habitats brought populations into contact that might otherwise have been more separated. It is equally possible that the contact was simply an aspect of the normal range overlap between two populations that shared the same broad region.
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## The Modern Human Comparison
The discovery of Denisova 11 sits within a broader context of findings about archaic-modern human interbreeding that has developed over the past fifteen years and continues to develop. Understanding Denisova 11’s significance requires some appreciation of how the Neanderthal and Denisovan admixture findings fit into the larger story of human evolution.
Modern humans evolved in Africa, with the anatomically modern human form emerging from earlier Homo populations approximately 300,000 years ago, based on recent evidence from the Jebel Irhoud site in Morocco. Over the subsequent hundreds of thousands of years, modern human populations spread, contracted, diversified, and began the dispersals that eventually populated the entire planet.