Denisovan father, Neanderthal mother. This is what a team of scientists from the Max Planck Institute for Evolutionary Anthropology (Germany) has discovered after sequencing the genome of an ancient hominin (the tribe that makes up the human being) from Siberia: the first human directly descended from two species.
The discovery of the remains took place in a cave in the remote Siberian mountains; The bone is barely two centimeters long, but analyzes have revealed that it belonged to an adolescent who lived more than 50,000 years ago and that her mother was a Neanderthal and her father a Denisovan, the two groups of extinct hominids that inhabited Eurasia as the modern humans.
“We knew from previous studies that Neanderthals and Denisovans must have had children at some point, but I never thought that we would be so lucky to find real offspring from the two groups,” explains Viviane Slon, MPI-EVA researcher and study co-author. published in the journal Nature . Specifically, the girl inherited 38.6% of her DNA and her mitochondrial DNA from a Neanderthal (the mother), and her Denisovan father contributed 42.3% of the girl’s DNA.
The result of the union of both species is only represented by a single, rather small bone fragment. “ The fragment is part of a long bone, and we can estimate that this individual was at least 13 years old, ” says Bence Viola of the University of Toronto, a co-author of the work.
Thanks to a stroke of luck
The bone fragment was found in 2012 in the Denisova Cave (Russia) by Russian archaeologists. It was brought to Leipzig for genetic analysis after it was identified as a hominid bone based on its protein composition.
“An interesting aspect of this genome is that it allows us to learn things about two populations: Neanderthals from the mother and Denisovans from the father,” explains Fabrizio Mafessoni from MPI-EVA, co-author of the study. The researchers determined that the mother was genetically closer to the Neanderthals living in Western Europe than to a Neanderthal individual who previously lived in Denisova Cave. This shows that Neanderthals migrated between western and eastern Eurasia tens of thousands of years before their disappearance.
Genome analyzes also revealed that the Denisovan father had at least one older Neanderthal ancestor in his family tree. “So, from this single genome, we can detect multiple instances of interactions between Neanderthals and Denisovans, ” says Benjamin Vernot, also a co-author of the study.
In fact, it is believed that approximately 2% of the genome of modern non-African humans is derived from the Neanderthal, and that some peoples of Oceania now have approximately 5% Denisovan DNA.
“ Neanderthals and Denisovans may not have had many opportunities to meet, but when they did, they must have mated frequently, much more than we thought, ” says Svante Pääbo, Director of the Department of Evolutionary Genetics at MPI-EVA and author principal of the study.
Neanderthals and Denisovans could have been further intermixed by the fact that the former settled mainly in Europe, and the latter settled in central and eastern Asia, the researchers speculated.
Reference: Viviane Slon et al, The genome of the offspring of a Neanderthal mother and a Denisovan father, Nature (2018). DOI: 10.1038 / s41586-018-0455-x
