Anthropology: A genetic snapshot of Neanderthal families

The first known description of relationships and social organization of a small community of Neanderthals is revealed in a paper published in Nature this week. The findings — based on an analysis of the ancient DNA of 13 Neanderthal individuals from two caves in Asia — provide new insights into the social organization of Neanderthals. It is the largest known genetic study of Neanderthals reported to date.

Neanderthals occupied western Eurasia from around 430,000 to 40,000 years ago and are closely related to modern humans. Genetic data in the form of nuclear DNA retrieved from the remains of a total 18 Neanderthal individuals (reported in a number of individual studies) so far have provided a broad review of the population. However, little is known about their social organization.

Laurits Skov and colleagues obtained and analysed genetic data from the remains of 11 Neanderthal individuals from Chagyrskaya Cave and 2 from Okladnikov Cave in the Altai Mountains of southern Siberia, Russia. The authors found that some Chagyrskaya individuals were closely related, including a father and his teenage daughter, along with a pair of second-degree relatives. The results indicate that at least some of them lived around the same time. The authors also found that the genetic diversity of Y chromosomes (passed down the male line) is a lot lower than that of the mitochondrial DNA (passed from mothers) in these individuals, which suggests that females were more likely to migrate than males. The authors propose that the findings can be best explained by a small community size (around 20 individuals) where 60% or more of females migrated from another community to join their mates’ families while the males stayed put.

The authors cautioned that the sample size is small and may not be representative of the social lives of the whole Neanderthal population. Therefore, future studies should aim to include more individuals from other communities to shed more light on the social organizations of our close cousins.