Kinship and social organization in Copper Age Europe. A cross-disciplinary analysis of archaeology, DNA, isotopes, and anthropology from two Bell Beaker cemeteries.

We present a high-resolution cross-disciplinary analysis of kinship structure and social institutions in two Late Copper Age Bell Beaker culture cemeteries of South Germany containing 24 and 18 burials, of which 34 provided genetic information. By combining archaeological, anthropological, genetic and isotopic evidence we are able to document the internal kinship and residency structure of the cemeteries and the socially organizing principles of these local communities. The buried individuals represent four to six generations of two family groups, one nuclear family at the Alburg cemetery, and one seemingly more extended at Irlbach. While likely monogamous, they practiced exogamy, as six out of eight non-locals are women. Maternal genetic diversity is high with 23 different mitochondrial haplotypes from 34 individuals, whereas all males belong to one single Y-chromosome haplogroup without any detectable contribution from Y-chromosomes typical of the farmers who had been the sole inhabitants of the region hundreds of years before. This provides evidence for the society being patrilocal, perhaps as a way of protecting property among the male line, while in-marriage from many different places secured social and political networks and prevented inbreeding. We also find evidence that the communities practiced selection for which of their children (aged 0-14 years) received a proper burial, as buried juveniles were in all but one case boys, suggesting the priority of young males in the cemeteries. This is plausibly linked to the exchange of foster children as part of an expansionist kinship system which is well attested from later Indo-European-speaking cultural groups.

Sex identification of ancient DNA samples using a microfluidic device.

Ancient DNA is the name given to the degraded, fragmented, and chemically damaged biomolecules that can be recovered from archaeological remains of plants, animals, and humans. Where ancient human DNA has survived at archaeological sites, it can give valuable information and is especially useful for its potential to identify kinship, population affinities, pathogens, and biological sex. Here, we describe the operation of a microfluidic device for the sex identification of ancient DNA samples using an efficient sample handling process. DNA is extracted from powdered bone samples and abasic sites labeled with biotin. Streptavidin-coated superparamagnetic particles are used to isolate the labeled DNA prior to amplification of the Amelogenin sex marker.

Brief communication: identification of the authentic ancient DNA sequence in a human bone contaminated with modern DNA.

We present a method to distinguish authentic ancient DNA from contaminating DNA in a human bone. This is achieved by taking account of the spatial distribution of the various sequence families within the bone and the extent of degradation of the template DNAs, as revealed by the error content of the sequences. To demonstrate the veracity of the method, we handled two ancient human tibiae in order to contaminate them with modern DNA, and then subjected segments of the bones to various decontaminating treatments, including removal of the outer 1-2 mm, before extracting DNA, cloning, and obtaining a total of 107 mitochondrial DNA sequences. Sequences resulting from the deliberate contamination were located exclusively in the outer 1-2 mm of the bones, and only one of these 27 sequences contained an error that could be ascribed to DNA degradation. A second, much smaller set of relatively error-free sequences, which we ascribe to contamination during excavation or curation, was also located exclusively in the outer 1-2 mm. In contrast, a family of 72 sequences, displaying extensive degradation products but identifiable as haplogroup U5a1a, was distributed throughout one of the bones and represents the authentic ancient DNA content of this specimen.