Together with their sister group the Neanderthals, Denisovans are the closest extinct relatives of currently living humans. “We knew from previous studies that Neanderthals and Denisovans must have occasionally had children together,” says Viviane Slon, researcher at the MPI-EVA and one of three first authors of the study. “But I never thought we would be so lucky as to find an actual offspring of the two groups.”
Well, it’s lucky for sure, but it’s the sort of thing we might expect to exist. We just want our team, institution, or country to get the credit.
Analyses of the genome also revealed that the Denisovan father had at least one Neanderthal ancestor further back in his family tree. “So from this single genome, we are able to detect multiple instances of interactions between Neanderthals and Denisovans,” says Benjamin Vernot from the MPI-EVA, the third co-author of the study.
“It is striking that we find this Neanderthal/Denisovan child among the handful of ancient individuals whose genomes have been sequenced,” adds Svante Pääbo, Director of the Department of Evolutionary Genetics at the MPI-EVA and lead author of the study. “Neanderthals and Denisovans may not have had many opportunities to meet. But when they did, they must have mated frequently — much more so than we previously thought.” Paper. (paywall) – Viviane Slon, Fabrizio Mafessoni, Benjamin Vernot, Cesare de Filippo, Steffi Grote, Bence Viola, Mateja Hajdinjak, Stéphane Peyrégne, Sarah Nagel, Samantha Brown, Katerina Douka, Tom Higham, Maxim B. Kozlikin, Michael V. Shunkov, Anatoly P. Derevianko, Janet Kelso, Matthias Meyer, Kay Prüfer, Svante Pääbo. The genome of the offspring of a Neanderthal mother and a Denisovan father. Nature, 2018; DOI: 10.1038/s41586-018-0455-x More.
But why did we “previously” think they wouldn’t get together?
Also: from ArsTechnica:
The authors argue that, despite the indications left in modern genomes, Denisova 11 strongly suggests that interbreeding was common whenever two different groups overlapped. After all, we don’t have a lot of genomes from archaic humans, and we’ve already found one that’s the direct product of interbreeding between two groups.
By contrast, modern humans seem to have displaced archaic ones fairly rapidly, suggesting there was a limited time window in which interbreeding could have taken place. Still, the clear signs of interbreeding and apparent past willingness to live together may indicate that the modern humans absorbed earlier populations rather than completely displacing them. John Timmer, “DNA shows girl had one Neanderthal, one Denisovan parent” at Ars Technica
Two longstanding Darwinian myths are threatened by these types of finds: One is the “missing link,” the not-quite-human, that we hardly expected to interbreed. In any Darwinian scheme, someone must be the subhuman. But the position seems currently vacant…
The second myth is the notion that life is a war of all against all for the survival of the fittest. Thus according to the myth, current humans got where we are by exterminating other lineages. The historical reality of which we have evidence is closer to what these researchers see when studying archaic populations: “modern humans absorbed earlier populations rather than completely displacing them.” Put simply, members of smaller or dwindling groups must often have children with members of more numerous groups if they are to have any at all, thus accelerating the assimilation process. If the larger group are migrants into the territory, the advance guard is usually young, unattached men, who speed up the assimilation process even further. No one doubts that there was a lot of violence back then but violence isn’t the main driver in such a story.
Note: Yes, that title is a pop culture reference.
See also: In any Darwinian scheme, someone must be the subhuman. Otherwise, there is no beginning to human history.
Do racial assumptions prevent recognizing Homo erectus as fully human?