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Ancient DNA reveals first Neanderthal family portrait

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Meet the Neanderthals in Chagyrskaya Cave.

About 54,000 years ago, the riverbank hunting camp at the foot of the Altai mountains in Siberia was home to a tight-knit community of about 20 people, including a father and young daughter, and a young man who could be their nephew or cousin. and an adult female second-degree relative—perhaps an aunt or grandmother.

Once the girl found a mate, she would likely move away from her father and family group. Had it been a man like her younger cousin, she would probably have stayed where she was. However, the communities to which he migrated likely contained familiar faces.

These are some of the intimate details of the Neanderthal family and social life, uncovered by examining the remains of two individuals from nearby Okladnikov Cave, as well as ancient DNA from 11 former residents of Chagyrskaya Cave.

It is the oldest known family group, and for the first time scientists have been able to directly document the fabric of a Neanderthal family and community, making our ancient cousins ​​appear much more human-like.

“It’s also very exciting that they’re alive. This means that they probably come from the same social community. “Therefore, for the first time, we can use genetics to study the social organization of a Neanderthal community,” study co-author Laurits Skov, a researcher at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, said in a news release. (“Neanderthal” is an alternative German spelling.)

The researchers extracted DNA from 17 bones and teeth that once belonged to seven male and six female Neanderthals, eight adults and five children.

They were able to unravel many of the genetic ancestral strands: mitochondrial DNA following the maternal line; Y chromosome DNA inherited from the male lineage; and nuclear DNA.

The researchers found several heteroplasmies in mitochondrial DNA, distinctive genetic signatures shared among individual Neanderthals that persisted for only a small number of generations. The researchers said this phenomenon suggests that the Neanderthals they studied at Chagyrskaya Cave lived and died at the same time.

They also found that the genetic diversity of Y chromosome DNA is much lower than that of mitochondrial DNA passed down from mothers. The study calculated that two male individuals in this group could expect to share an ancestor about 450 years before they lived. In contrast, the equivalent estimate for female individuals was about 4,350 years.

The researchers suggest that the best explanation for this is that more than 60% of female Neanderthals, had emigrated from another community in the small Chagyrskaya group. This social structure is common in today’s hunter-gatherer societies and is known as patrilocality.

More broadly, the community had extremely low genetic diversity—far lower than what has been recorded for any ancient or present-day human population, the study said. The level of diversity was more similar to group sizes of endangered species such as mountain gorillas with a population of about 1000.

But the lack of genetic diversity wasn’t necessarily a major factor in the extinction of the Neanderthals that disappeared around, said Chris Stringer, human evolution research leader at the Natural History Museum in London, who was not involved in the research. 40,000 years ago. Said other Neanderthal sites that were active. It shows larger and more diverse populations around the same time as the group studied, such as Vindija in Croatia.

The study authors said the family group they uncovered may not be representative of the social life of the entire Neanderthal population. They suggested future research involving genetic sequencing. more Neanderthal individuals and populations.

The inhabitants of the two caves likely interacted—hiking to the same rock springs to make their stone tools—supporting the genetic link between them. Neanderthals hunted mountain goats, horses, bison, and other animals that crossed river valleys overlooked by caves.

Chagyrskaya and Okladnikov are 100 kilometers (62 miles) from Denisova Cave, one of the most important sites in the study of human evolution. This region was occupied by Neanderthals, early modern humans, and Denisovans, a more recently identified extinct human species discovered from DNA taken from a single pinky finger.

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

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

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