GERMANY: A family of Neanderthals camped up in a cave high in the Altai Mountains of Siberia more than 49,000 years ago, looking out over a river valley where bison, red deer, and wild horses grazed. A teenage girl who was chewing on bison that her father or one of his relatives had likely hunted in the expansive plains lost a tooth in the cave’s main gallery.
Now, scientists have examined the genomes of this father and daughter as well as 12 of their ancestors, many of whom spent fewer than 100 years hiding in the same cave. Ancient genomes provide a unique look at Neanderthal family groups.
The new genomes nearly treble the number of Neanderthal genomes that are currently known and provide a glimpse into the population of Neanderthals at the eastern end of their range when they were on the verge of extinction.
The genomes also provide the first concrete hints about a group of Neanderthals’ social organization. According to geneticist Laurits Skov of the Max Planck Institute for Evolutionary Anthropology, the genetic evidence not only helped to identify the first father-daughter pair but also implies that these boys remained in their family groupings as adults, like men in many contemporary human communities. He gave a virtual session about the research earlier this month at the Seventh International Symposium on Biomolecular Archaeology.
The fact that they could obtain seven males’ genomes at one location is quite amazing, according to Tübingen University paleogeneticist Cosimo Posth. “It is in fact indicating that they lived in tiny groups of closely related guys for this group in this cave.”
Geneticists have sequenced the genomes of 19 Neanderthals in the last ten years. But between 400,000 and 50,000 years ago, that DNA primarily originated from females who were distantly related and lived at various sites throughout Europe and Asia.
The new work was headed by Max Planck researchers Benjamin Peter, a computational biologist, and Svante Pääbo, a paleogeneticist, along with postdoc Skov. They retrieved Neanderthal DNA from teeth, bone fragments, and a jawbone discovered by archaeologists from the Russian Academy of Sciences in Novosibirsk during continuing digs at Chagyrskaya and Okladnikov caves.
Along with postdoc Skov, the new research was led by computational biologists Benjamin Peter and Svante Pääbo of Max Planck. From teeth, bone fragments, and a jawbone found by archaeologists from the Russian Academy of Sciences in Novosibirsk during ongoing excavations at Chagyrskaya and Okladnikov caves, they were able to recover Neanderthal DNA.
The researchers examined DNA from more than 700,000 places throughout the genomes of a male and a female from Okladnikov and seven males and five females from Chagyrskaya. They discovered relatives: One piece of the Chagyrskaya bone contained nuclear DNA connecting the father to the tooth his adolescent daughter had lost.
Some people had two distinct maternally inherited mitochondrial DNA types (mtDNA). The folks must have lived in the same century because their genomes hadn’t yet differentiated from one another, which takes a few generations to occur.
The DNA revealed more details about Neanderthal culture. Long stretches of identical nuclear DNA from the same recent progenitor were seen in several Chagyrskaya males. Their Y chromosomes had characteristics similar to those of the only three male Neanderthal genomes that originated from a modern human ancestor. Their nuclear DNA also revealed a stronger genetic connection to later Neanderthals in Spain than to early ones at the nearby Denisova, suggesting migration.
The similarities between the males imply that they belonged to a population of just a few hundred breeding males, or around the same number that is currently observed among critically endangered mountain gorillas.
Skov claims that the Neanderthal population would be in danger “If you were to think of this group as [populations today].”
The mtDNA of both males and females was relatively diverse, in contrast to the Y chromosome and nuclear DNA, suggesting that more female ancestors than males contributed to the population. That might be a founder effect, where there were less fertile males in the beginning group than there were fertile females.
Paleogeneticist Qiaomei Fu of the Chinese Academy of Sciences, who attended the discussion, speculates that it may also reflect the characteristics of Neanderthal civilization. She claims that either “Women travelled more often across groups, or fewer men contributed to the following generation.”
According to Skov, the proof points to the latter. According to him, modelling studies demonstrate it’s implausible that a tiny migrant group moving into Siberia from Europe would contain mainly females and few males.
He believes that these Neanderthals actually lived in tiny groups of between 30 to 110 breeding adults, and those young females abandoned their own families to live with their partners’ families. The patrilocal nature of most modern human societies highlights yet another similarity between Neanderthals and contemporary people.
Posth warns that only 14 genomes can provide information about all Neanderthals’ social interactions. The lack of diversity among the guys, though, worries him. Our closest relatives’ time on Earth was quickly coming to an end; they would vanish in just 5000 to 10,000 years.