Ancient DNA reveals first Neanderthal family portrait

The riverside hunting camp at the foot of the Altai Mountains in Siberia was home to a restricted community of about 20 inhabitants some 54,000 years ago, including a father and his teenage daughter, a young man who could have been a nephew. or cousin, and an adult female second-degree relative – perhaps an aunt or grandmother.

The girl would likely have drifted away from her father and family group when she found a mate. If she were a boy, like her younger cousin, she probably would have stayed. However, the communities she migrated to likely contained familiar faces.

These are some of the intimate details of the Neanderthal family and social life revealed by an ancient DNA study that belonged to 11 former Chagyrskaya Cave dwellers, as well as the remains of two others from the nearby Okladnikov Cave.

It’s the oldest known family group and the first time scientists have been able to directly document the tissue of a Neanderthal family and community, making our ancient cousins ​​look much more human.

“The fact that they are living at the same time is very exciting. That means they likely came from the same social community. So, for the first time, we can use genetics to study the social organization of a Neanderthal community,” said study co-author Laurits Skov, a researcher at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, in a press release.

The researchers extracted DNA from 17 bones and teeth that belonged to seven Neanderthal men and six women, eight of whom were adults and five were children.

genetic threads

They were able to unravel multiple strands of genetic ancestry: mitochondrial DNA, which follows the maternal line; DNA from the Y chromosome, which is inherited through the male line; and nuclear DNA.

In mitochondrial DNA, the researchers found several heteroplasmies — distinct genetic signatures that only persist for a small number of generations — that were shared among individual Neanderthals. This phenomenon, the researchers said, suggests that the Neanderthals they studied at Chagyrskaya Cave must have lived and died at the same time.

They also found that the genetic diversity of Y-chromosome DNA was much lower than that of mitochondrial DNA, which is passed on from mothers. The study calculated that, in this group, two males could expect to share an ancestor about 450 years before they lived. On the other hand, the equivalent estimate for females was around 4,350 years old.

The researchers said the best explanation for this is that more than 60% of Neanderthal women in the small Chagyrskaya group migrated from another community. This social structure is common among hunter-gatherer societies today and is known as patrilocality.

More broadly, the community had extremely low genetic diversity — far lower than any recorded for any ancient or current human community, the study said. The level of diversity was more similar to the size of groups of endangered species on the brink of extinction, such as mountain gorillas, which have a population of around 1,000 individuals.

However, Chris Stringer, research leader in human evolution at the Natural History Museum in London, who was not involved in the research, said the lack of genetic diversity was not necessarily a significant factor in the extinction of the Neanderthals, who disappeared around 12:00. 40 thousand years ago. He said other Neanderthal sites that were active around the same time as the group studied, such as Vindija in Croatia, indicate larger and more diverse populations.

The study authors said the family group they found may not be representative of the social life of the entire Neanderthal population. They recommended future research that includes genetic sequencing of more Neanderthal individuals and communities.

first family photo

The inhabitants of the two caves likely interacted – walking to the same rock sources to make their stone tools – supporting the genetic link between them. Neanderthals hunted ibex (goat bovid mammal), horses, bison and other animals that traveled through cave river valleys.

Chagyrskaya and Okladnikov are within 100 kilometers of Denisova Cave – one of the most important sites in the study of human evolution. This site was occupied by Neanderthals, early modern humans and Denisovans, a more recently identified type of extinct human that was discovered from DNA recovered from a single pinky finger.

Svante Pääbo, another co-author of the Chagyrskaya study, sequenced the first Neanderthal genome in 2010, work for which he received a Nobel Prize earlier this month. Since that initial sequencing, genome-wide data has been recovered from a total of 18 Neanderthals. The new study adds another 13 — a major technical achievement, said Lara Cassidy, an assistant professor in the Department of Genetics at Trinity College Dublin, who was not involved in the research.

“What makes this work particularly remarkable is that the sequenced individuals are not widely spread across the vast expanse of Neanderthal existence, but are concentrated at a specific point in time and space, thus providing the first snapshot of a family group,” she said. in a commentary posted alongside the study.