By Will Dunham
WASHINGTON – Remains of bones and teeth from two Siberian caves are helping scientists decipher the social organization of our cousins the Neanderthals for the first time through genetic research, including the remains of a father and his daughter teenage girl.
Researchers on Wednesday described genomic findings from the remains of 13 Neanderthals – 11 from Chagyrskaya Cave and two from Okladnikov Cave in Russia’s Altai Mountains – in one of the largest genetic studies of a Neanderthal population to date. Paleolithic remains date back approximately 54,000 years.
Piecing together the relationships between some of these individuals based on the genetic findings has allowed researchers to conclude that these Neanderthal communities were made up of a small group of close relatives, perhaps consisting of 10 to 20 members, and that these were the women who migrated between communities, the men remaining in place.
The caves are located at the easternmost point of the known geographic range of Neanderthals, who inhabited parts of western Eurasia, while another now-extinct human lineage called the Denisovans occupied parts from eastern Eurasia.
The caves are located less than 100 km from the site where the earliest Denisovan remains were found, but the study detected no evidence of interbreeding between these 13 Neanderthals and Denisovans. Our species had not yet reached this region at the time.
While genomic analyzes of Neanderthals have already provided information about their population history and their close relationship to our species, their social organization has been more difficult to reconstruct.
“I think our ideas make Neanderthals easier to understand and, in a way, more human. They were people who lived and died in small family groups, probably in a hostile environment. Yet they managed to persevere for hundreds of thousands of years,” said population geneticist Benjamin Peter of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, co-author of the research published in the Nature magazine.
Neanderthals, more robust than Homo sapiens and with larger eyebrows, lived from around 430,000 to around 40,000 years ago.
The 13 Neanderthal individuals included five children and teenagers. There were seven men and six women.
The Chagyrskaya Cave site yielded the remains of an adult male father and his teenage daughter, thought to have been in her late teens. There was also a boy between 8 and 12 years old, based on dental evidence, as well as an adult female relative whose genetic findings suggested he was an aunt, cousin or grandfather. -mother.
Scientists have found numerous stone tools and animal bones in both caves, suggesting small hunter-gatherer communities whose members hunted bison, ibex, horses and other animals that migrated through the caves. river valleys below these caves.
Far from the outdated stereotype of stupid brutes, studies have shown that Neanderthals were intelligent, creating art, using complex methods of hunting in groups, pigments probably for body paint, symbolic objects and possibly language speak.
The low genetic diversity – similar to that of endangered species on the brink of extinction – found among the 13 Neanderthals in the research provided evidence for the small group sizes of these communities.
The researchers compared the genetic diversity on the Y chromosome – the one inherited from father to son – to that of the mitochondria DNA diversity – inherited from mothers. The greater mitochondrial genetic diversity indicated that these communities were primarily linked by the movement of females from one to another.
The nature of the interaction between our species and Neanderthals – formally called Homo neanderthalensis – remains unclear. There has been interbreeding, as shown by the fact that non-African modern human populations carry residual Neanderthals DNA. But our role in their extinction remains unclear. The Neanderthals disappeared relatively soon after our species settled in their territory, as did the Denisovans as well.
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