Genetic study discovers first family of Neanderthals in Siberian cave

A genetic study, published on Wednesday (19), outlines the contours of a “social organization” of the same family of Neanderthals who lived more than 50,000 years ago in a cave in Siberia.

The sequencing, in 2010, of the genome of Neanderthal man by Svante Paabo from Sweden, recently awarded the Nobel Prize in Medicine, allowed us to trace the history of this extinct lineage, which populated western Eurasia between 430,000 and 40,000 years ago.

Thanks to archaeological excavations, it is known that some Neanderthals buried their dead, made tools and even adornments, far from the image of primitive brutes that accompanied them for a long time.

But little is known about its social structure. The genetic sequencing of an entire group of individuals, the largest ever performed on these hominids, brings some elements.

The story takes place in southern Siberia, Russia, a region particularly fruitful for the search for ancient DNA, as the cold helps conserve this fragile and precious indicator of the past.

There, the genome of the Denisovan man – another extinct human race – was discovered in the cave of the same name, recalls a statement from the Max Planck Institute for Evolutionary Anthropology in Leipzig (Germany), where work published in the journal Nature was carried out.

About 100 kilometers away are the Chagyrskaya and Okladnikov caves, which were occupied by Neanderthals about 54,000 years ago.

There, several remains had already been recovered in a single layer of deposits, which indicated that the occupants had lived in approximately the same period.

To prove it, it was necessary to make the DNA talk, a more complicated task because they were not complete skeletons, but scattered teeth and bone fragments.

“First, we had to identify how many individuals we had”, explains paleontologist Stéphane Peyrégne, one of the main authors of the study, to AFP.

His team used new techniques to isolate ancient human DNA – often steeped in microbial contamination – and capture it.

It was confirmed that the remains came from 13 Neanderthals (7 men and 6 women, including five children or adolescents), 11 of them were in the Chagyrskaya cave.

important inbreeding

In their mitochondrial DNA – transmitted by the mother – the researchers found the same genetic variant, heteroplasmy, which persists only in a few generations.

The genes also revealed close kinship ties: a father and his teenage daughter, a boy and an adult woman who would have been his cousin, aunt, or grandmother.

They are direct evidence that these people belonged to the same family and lived at the same time.

Thanks to genetics, “we’ve produced a concrete picture of what a Neanderthal community might have looked like,” says Benjamin Peter, who supervised the research with Svante Paabo.

The group in question, genetically close to the Neanderthals of western Europe, did not mix with other species – sapiens and denisova – as other Neanderthals did at other times.

Its genetic diversity is, on the other hand, very fragile, a sign of an important consanguinity and a life in a small group, composed of 10 to 20 individuals, many smaller than the ancient communities of Homo sapiens.

“It’s probably a very subdivided population”, but it didn’t live completely isolated, explains Stéphane Peyrégne.

Women would have tended to emigrate from community to community to procreate, with men remaining in their clan of origin.

This “patrilocal” functioning, which also prevailed in Sapiens, is suggested due to a genetic diversity of the Y chromosomes (transmitted by the male lineage), much more fragile than the mitochondrial DNA, transmitted only by the mother.

This organization had already been anticipated after the discovery of fossils in the El Sidrón cave in Spain, but based on less complete genetic material, notes paleontologist Antoine Balzeau, who was not involved in the study.

“It’s a very interesting technical feat for our research, although we have to compare it with other groups,” replied this researcher at the National Museum of Natural History.