Humans are the only living species of the Homo lineage, but tens of thousands of years ago, our ancestors shared turf—and occasionally even offspring—with close hominin relatives.
Denisova Cave, in the Altai Mountains of Siberia, was a popular hangout spot for all these human(ish) creatures. Bones indicate that this location was inhabited by early humans, Neanderthals, and Denisovans, a third ancient hominin species named after the cave.
Now, for the first time, scientists have identified an individual with a Neanderthal mother and a Denisovan father, from a cave bone called “Denisova 11.” According to research published on Wednesday in Nature, genome sequencing of Denisova 11 revealed that this individual was an adolescent female who lived 50,000 years ago, and who was at least 13-years-old when she died.
“In conjunction with the presence of Neanderthal and Denisovan DNA in ancient and present-day people, this suggests that mixing among archaic and modern hominin groups may have been frequent when they met,” the researchers wrote.
Led by Viviane Slon, an ancient DNA expert at the Max Planck Institute for Evolutionary Anthropology, the team used a technique called peptide mass fingerprinting to probe the intricacies of this young girl’s ancestry. The results showed that “38.6% of fragments from Denisova 11 carried alleles matching the Neanderthal genome and 42.3% carried alleles matching the Denisovan genome,” according to the paper.
The researchers considered the possibility that Denisova 11 was not the direct offspring of a Denisovan and a Neanderthal, but one member of a mixed Neanderthal-Denisovan population at the cave. However, genetic models showed that the near-equal contributions of Neanderthal and Denisovan DNA was a far better match for the scenario in which the individual’s parents descended from distinct hominin lineages.
Denisova 11’s genome also contained interesting insights about her parents’ background. By cross-referencing the maternal DNA against other Neanderthal genomes, Slon and her colleagues found that the mother was more closely related to a group of Neanderthals known to have inhabited Western Europe than she was to other Neanderthals found at Denisova Cave. The Denisovan father was revealed to have some Neanderthal ancestry, further corroborating a history of genetic exchange between hominin species across Eurasia.
Humans, Neanderthals, and Denisovans all remained distinct lineages, separated by genetics, geography, and perhaps even culture until the latter two died out around 40,000 years ago. But as more remains are discovered and more genomes are sequenced, it’s clear that these groups also left a tangled web of mixed heritage for modern scientists to document.
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This article originally appeared on VICE US.