The picture that emerges—from Denisova 11 and from the population genetics research on both groups—is of populations that were distinct but not isolated. They overlapped in range, at least in some regions and at some time periods. They occasionally interbred. The resulting offspring sometimes survived and sometimes reproduced. The genetic flow was real but limited.
This pattern is, actually, familiar from the modern world. Many mammal species that are closely related but ecologically distinct occasionally interbreed where their ranges overlap, producing rare hybrids that sometimes survive but rarely disrupt the genetic distinctiveness of the parental populations. The Neanderthal-Denisovan relationship may have been something like this: two groups distinct enough to have maintained separate evolutionary trajectories across hundreds of thousands of years, closely enough related that reproduction was possible and occasionally occurred, with the resulting individuals sometimes contributing to later populations and sometimes not.
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## The Timing and Context of the Encounter
The dating evidence places Denisova 11 at approximately 90,000 years ago. This is a significant temporal context.
Ninety thousand years ago, modern humans were present in Africa and may have been present in parts of the Middle East—there is evidence from Israeli sites like Qafzeh and Skhul of anatomically modern humans dating to approximately 100,000 to 130,000 years ago—but the major dispersal of modern humans out of Africa and across Eurasia had not yet begun in the form that eventually replaced all archaic human populations. The Altai Mountains at 90,000 years ago were inhabited by archaic human populations. The archaic populations that lived there—Neanderthals, Denisovans, and now Denisova 11—are the primary story.