Genetic insights into the social organization of Neanderthals

Abstract Genomic analyses of Neanderthals have previously provided insights into their population history and relationship to modern humans¹–⁸, but the social organization of Neanderthal communities remains poorly understood. Here, we present genetic data for 13 Neanderthals from two Middle Palaeolithic sites in the Altai Mountains of southern Siberia: 11 from Chagyrskaya Cave⁹,¹⁰ and two from Okladnikov Cave¹¹ - making this the largest genetic study of a Neanderthal population to date. We used hybridization capture to obtain genome-wide nuclear data, as well as mitochondrial and Y-chromosome sequences. Some Chagyrskaya individuals were closely related, including a father-daughter pair and a pair of second degree relatives, indicating that at least some of the individuals lived at the same time. Up to a third of these individuals’ genomes occur in long segments of homozygosity, suggesting that the Chagyrskaya Neanderthals were part of a small community. In addition, the Y-chromosome diversity is an order of magnitude lower than the mitochondrial diversity, a pattern that we found is best explained by female migration between communities. Thus, the genetic data presented here provide a detailed documentation of the social organization of an isolated Neanderthal community at the easternmost extent of their known range.