by Tomás Pizarro-Escuti
More than 50,000 years ago, a Neanderthal woman and a Denisovan man interbred and a few months later they gave birth to a girl. Many centuries later, in a Siberian cave near the Altai mountains, the bones left by that hybrid woman, who was about 13 years old when she died, were found. For almost a decade it has been known that Neanderthals, Denisovans and modern humans had offspring in some circumstances, but never had a child of a mixed couple been found until now.
Nature magazine has published the genome of the first of these humans. A team led by Viviane Slon and Svante Pääbo, from the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, analysed the DNA extracted from a bone fragment of the young woman and concluded that the mother was Neanderthal, and the father was Denisovan. This links the adolescent with the lineage of a well-known species, the makers of the first known artistic expressions of history, whose bones and tools are spread throughout Europe. But also, her father makes her the descendant of a much more mysterious group, known only from the genetic analysis of small fragments of bone found only in the Russian cave of Denisova.
Previous genetic studies have shown that there was hybridization between the two groups and with our species, as traces have been found in the DNA of the modern human. However, this study is the first to identify a first-generation descendant of Neanderthal and Denisovan parents. "It's fascinating to find direct proof of this hybridization," said Svante Paabo, one of the authors of the study. The genomes of the two species, also sequenced by Pääbo and his collaborators, indicate that they separated more than 390,000 years ago. However, they continued to procreate in a timely manner in the territories where both species shared a border. "Although we still do not know the anatomy of Denisovans [only fragments of bones and teeth have been found], I believe that, although they would not be the same, anatomically they would not be very different," explains Juan Luis Arsuaga, co-director of Atapuerca. "The Denisovans would be something like the Asian version of the Neanderthals," he adds.
This great discovery helps to confirm the theory that extinct ancient lineages could have been absorbed through hybridization with modern human beings, rather than having been eliminated by warfare- as it is commonly thought.