Meet the first Neanderthal family

The first draft Neanderthal genome was published in 2010. Since then, researchers at the Max Planck Institute for Evolutionary Anthropology have sequenced another 18 genomes from 14 different archaeological sites across Eurasia. While these genomes have provided glimpses into the broader traits of Neanderthal history, we still know little about individual Neanderthal communities.

To explore the social structure of Neanderthals, the researchers turned their attention to southern Siberia, a region that had previously been very fertile for studying ancient DNA – including the discovery of Denisova people in the famous Denisova Cave. From work at this site, we know that Neanderthals and Denisovans were present in this region for hundreds of thousands of years, and that Neanderthals and Denisovans interacted with one another – like discovering a child with a Denisovan father and a Neanderthal mother has shown.

First Neanderthal community

In their new study published in Naturethe researchers focused on the Neanderthal remains in the Chagyrskaya and Okladnikov Caves, located within 100 kilometers of Denisova Cave. Neanderthals briefly occupied these sites around 54,000 years ago, and several potentially contemporaneous Neanderthal remains have been recovered from their deposits. The researchers successfully extracted DNA from 17 Neanderthal remains – the largest number of Neanderthal remains ever sequenced in a single study.

Chagyrskaya Cave has been excavated over 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 have also recovered more than 80 Neanderthal bone and tooth fragments, one of the largest collections of these fossil humans not only in the region, but also worldwide.

The Neanderthals at Chagyrskaya and Okladnikov hunted ibex, horses, bison and other animals that migrated through the river valleys overlooking the caves. They gathered raw materials for their stone tools dozens of kilometers away, and the occurrence of the same raw material in both the Chagyrskaya and Okladnikov Caves also supports the genetic data that the groups inhabiting these sites were closely related.

Previous studies of a fossil toe from Denisova Cave showed that Neanderthals also inhabited the Altai Mountains much earlier, around 120,000 years ago. However, genetic data show that the Neanderthals from the Chagyrskaya and Okladnikov Caves are not descendants of these earlier groups, but are more closely related to the European Neanderthals. This is also supported by the archaeological material: The stone tools from the Chagyrskaya Cave are most similar to the so-called Mikoquien culture known from Germany and Eastern Europe.

The 17 remains belonged to 13 Neanderthals – 7 males and 6 females, including 8 adults and 5 children and adolescents. In their mitochondrial DNA, the researchers found several so-called heteroplasma that were shared by individuals. Heteroplasmias are a special type of genetic variant that lasts only a few generations.

The easternmost Neanderthal

Among these remains were those of a Neanderthal father and his teenage daughter. The researchers also found two second-degree relatives: a young boy and an adult woman, perhaps a cousin, aunt, or grandmother. The combination of heteroplasmies and related individuals strongly suggests that the Neanderthals in Chagyrskaya Cave must have lived—and died—around the same time.

“The fact that they lived at the same time is very exciting. That means they likely came from the same social community. Therefore, for the first time, we can use genetics to study the social organization of a Neanderthal community,” says Laurits Skov, the first author of this study.

Another notable finding is the extremely low genetic diversity within this Neanderthal community, which corresponds to a group size of 10 to 20 individuals. This is much lower than those recorded for any ancient or contemporary human community, and more closely resembles the group size of endangered species on the brink of extinction.

However, Neanderthals did not live in completely isolated communities. By comparing the genetic diversity on the Y chromosome, which is inherited from father to son, with the mitochondrial DNA diversity, which is inherited from mothers, the researchers were able to answer the question: was it the men or the women between changed communities? ?

They found that mitochondrial genetic diversity was much higher than Y chromosome diversity, suggesting that these Neanderthal communities were primarily linked through female migration. Despite the close proximity to the Denisovan Cave, these migrations do not appear to have involved Denisovan people – the researchers found no evidence of Denisovan gene flow in the Chagyrskaya Neanderthals for the last 20,000 years before these individuals lived.

“Our study provides a concrete picture of what a Neanderthal community might have looked like,” says Benjamin Peter, the senior author of the study. “It makes Neanderthals seem a lot more human to me.”