Chagyrskaya cave – BENZ VIOLA
Oct. 19 () –
For the first time, it has been possible to sequence 13 individuals from a Neanderthal community remote in Siberia, among which there are people relatedincluding a father and his teenage daughter.
An international team led by researchers from the Max Planck Institute for Evolutionary Anthropology have also been able to use the thirteen genomes to give insight into the social organization of a Neanderthal community, which appear to have been a small group of close relatives, consisting of ten to twenty membersand the communities were connected primarily through female migration, as published in the magazine ‘Nature’.
The first draft of the Neanderthal genome was published in 2010, and since then researchers at the Max Planck Institute for Evolutionary Anthropology in Germany have sequenced a further 18 genomes from 14 different archaeological sites across Eurasia. While these genomes have provided insight into the broad outlines of Neanderthal history, little is yet known of individual Neanderthal communities.
To explore the social structure of Neanderthals, the researchers turned their attention to southern Siberia, a region that has been very fruitful for ancient DNA research, including the discovery of Denisovan hominin remains in the famous Denisova cave. Thanks to the work carried out there, we know that Neanderthals and Denisovans were present in this region for hundreds of thousands of years, and that Neanderthals and Denisovans have interacted with each other, as the discovery of a child of a Denisovan father and a Neanderthal mother has shown.
In their new study, the researchers focused on Neanderthal remains from the Chagyrskaya and Okladnikov caves, which are less than 100 kilometers from the Denisova cave. Neanderthals briefly occupied these sites around 54,000 years ago, and multiple potentially contemporary Neanderthal remains have been recovered from their sites. The researchers managed to recover DNA from 17 Neanderthal remains, the largest number of Neanderthal remains ever sequenced in a single study.
The Chagyrskaya cave has been excavated for the past 14 years by researchers from the Institute of Archeology and Ethnography of the Russian Academy of Sciences. In addition to several hundred thousand stone tools and animal bones, they also recovered more than 80 Neanderthal bone and tooth fragments, one of the largest sets of these fossil humans not only in the region but in the world.
The Chagyrskaya and Okladnikov Neanderthals hunted ibex, horses, bison, and other animals that migrated through the river valleys that the caves overlook. They collected raw materials for their stone tools from tens of kilometers away, and the appearance of the same raw material in both the Chagyrskaya and Okladnikov caves also supports the genetic data that the groups that inhabited these localities were closely linked.
Previous studies of a fossil finger from Denisova Cave have shown that Neanderthals also inhabited the Altai Mountains much earlier, about 120,000 years ago. However, genetic data shows that Neanderthals from Chagyrskaya and Okladnikov caves are not descendants of these earlier groups, but are more closely related to European Neanderthals. Archaeological material also corroborates this claim, that the Chagyrskaya cave stone tools are the most similar to the so-called Micoquian culture known in Germany and Eastern Europe.
The 17 remains come from 13 Neanderthal individuals: 7 men and 6 women, of whom 8 were adults and 5 children and adolescents. In their mitochondrial DNA, the researchers found several so-called heteroplasmies that the individuals shared. Heteroplasmias are a special type of genetic variant that only persist for a small number of generations.
Among these remains were those of a Neanderthal father and his teenage daughter. The researchers also found a pair of second-degree relatives: a young man and an adult woman, perhaps a cousin, aunt or grandmother.. The combination of heteroplasmies and related individuals strongly suggests that the Chagyrskaya Cave Neanderthals must have lived – and died – at about the same time.
“The fact that they lived at the same time is very exciting. This means that they probably came from the same social community. So, for the first time, we can use genetics to study the social organization of a Neanderthal community.” it states it’s a statement Laurits Skov, first author of this study.
Another surprising finding for the researchers is the very low genetic diversity within this Neanderthal community, consistent with a group size of 10 to 20 individuals. This figure is much lower than those recorded in any ancient or current human community, and more closely resembles the size of groups of endangered species.
However, Neanderthals did not live in completely isolated communities. By comparing the genetic diversity of the Y chromosome, which is inherited from father to son, with the diversity of mitochondrial DNA, which is inherited from mothers, the researchers they were able to answer the question of whether it was men or women who moved between communities.
They found that mitochondrial genetic diversity was much greater than that of the Y chromosome, suggesting that these Neanderthal communities were primarily linked by female migration. Despite the proximity to Denisova Cave, these migrations do not appear to have involved Denisovans: the researchers found no evidence of flow Denisovan genetics in the Chagyrskaya Neanderthals in the last 20,000 years before these individuals lived.
“Our study offers a concrete picture of what a Neanderthal community could have been like,” said Benjamin Peter, last author of the study. It makes Neanderthals seem so much more human to me.”
