Fifty thousand year old DNA has provided the first-ever glimpse of a Neanderthal family. The remains located in a Siberian cave also revealed the fact that they traveled in small, family-oriented groups.
Researchers were able to take new genetic analysis from the fragmented bones and teeth of a father and his adolescent daughter alongside other Neanderthal bones in a cave in Siberia. They discovered this first-ever glimpse of a Neanderthal family in Chagyrskaya Cave in the snowy Altai Mountains. The cave is only about 60 miles (100 kilometers) west of Denisova Cave, which produced evidence of an extinct species of hominin called the Denisovans just over a decade ago.
Apparently, a group of adults and children died while sheltering at their hunting camp more than 50,000 years ago. What this latest find provides archaeologists and geneticists with is the most complete set of Neanderthal genomes to date.
Discovery of fossils and other remains
In 2019, excavators found stone artifacts, bone tools, animal and plant remains, and 74 Neanderthal fossils. At that time, they presumed the organic remains to be a short-term bison hunting camp as they were radiocarbon-dated sometime between 51,000 and 59,000 years old.
Pollen and animal remains show that the climate was quite cold in the short time Neanderthals occupied the Chagyrskaya Cave.
The journal Nature published a new analysis on October 19th. It delved even further into the gthe Chagyrskaya Neanderthals’ DNA and the neighboring Okladnikov Cave. The study yielded an astounding 13 genomes, nearly double the number of complete Neanderthal genome sequences in existence.
DNA analysis reveals Neanderthals lived in biologically related groups
While previous work estimated the size of Neanderthal communities based on footprints and site-use patterns, the new genomic analysis directly tested the hypothesis that Neanderthals lived in biologically related groups of 20 or fewer individuals.
The DNA from two individuals — an adult male and an adolescent female — suggested a “first-degree relationship,” meaning it was possible for them to be mother and son, brother and sister, or father and daughter. Yet their nonmatching mitochondrial DNA (mtDNA), which is generally passed on from mother to child, ruled out the first two pairings, leaving researchers face-to-face with a father and his teenage daughter.
The father also shared Neanderthal DNA with two other males, who were likely close maternal relatives. “For example, they could have shared a grandmother,” the authors suggested.
There is no evidence that these itinerant Neanderthals mingled with the nearby Denisovans. This, even though they were likely in the same place at the same time. The researchers estimated that the Denisovans shared a common ancestor perhaps 30,000 years before the Chagyrskaya Neanderthals. Furthermore, they discovered that the Chagyrskaya and Okladnikov individuals “all appear equally related to European Neanderthals and were part of the same Neanderthal population.”
Female migration of the Chagyrskaya Neanderthal community
High similarity in the genome segments of these Neanderthals also led the researchers to “conclude that the local community size of the Chagyrskaya Neanderthals was small.”
Fitting models to the mtDNA and Y-DNA, the latter of which is passed from fathers to their sons, the best scenario “assumed a community size of 20 individuals.” Female migration was “a major factor in the social organization of the Chagyrskaya Neanderthal community,” the study authors also wrote.
In essence, some females remained with the group they were born into. Yet there were many others who left their communities to join new ones. Researchers are not sure however if this group size could be applied outside the Altai region. That is because the Chagyrskaya group may have been a unique, isolated example. In fact, isolation might have been these Neanderthals’ undoing.
While speculating about the cause of death, paleo-geneticist and lead author Laurits Skov told The New York Times that they may have died from starvation after a poor bison hunt. Geochronologist and co-author Richard Roberts however told The Washington Post that “maybe it was just a horrendous storm. They are in Siberia, after all.”