Dairying, diseases and the evolution of lactase persistence in Europe

In European and many African, Middle Eastern and southern Asian populations, lactase persistence (LP) is the most strongly selected monogenic trait to have evolved over the past 10,000 years1. Although the selection of LP and the consumption of prehistoric milk must be linked, considerable uncertainty remains concerning their spatiotemporal configuration and specific interactions2,3. Here we provide detailed distributions of milk exploitation across Europe over the past 9,000 years using around 7,000 pottery fat residues from more than 550 archaeological sites. European milk use was widespread from the Neolithic period onwards but varied spatially and temporally in intensity. Notably, LP selection varying with levels of prehistoric milk exploitation is no better at explaining LP allele frequency trajectories than uniform selection since the Neolithic period. In the UK Biobank4,5 cohort of 500,000 contemporary Europeans, LP genotype was only weakly associated with milk consumption and did not show consistent associations with improved fitness or health indicators. This suggests that other reasons for the beneficial effects of LP should be considered for its rapid frequency increase. We propose that lactase non-persistent individuals consumed milk when it became available but, under conditions of famine and/or increased pathogen exposure, this was disadvantageous, driving LP selection in prehistoric Europe. Comparison of model likelihoods indicates that population fluctuations, settlement density and wild animal exploitation-proxies for these drivers-provide better explanations of LP selection than the extent of milk exploitation. These findings offer new perspectives on prehistoric milk exploitation and LP evolution.

Subdivisions of haplogroups U and C encompass mitochondrial DNA lineages of Eneolithic-Early Bronze Age Kurgan populations of western North Pontic steppe

Prehistoric Europe experienced a marked cultural and economic shift around 4000 years ago, when the established Neolithic agriculture-based economy was replaced by herding-pastoralist industry. In recent years new data about the genetic structure of human communities living during this transition period began to emerge. At the same time, the genetic identities of the Eneolithic and Early Bronze Age (EBA) inhabitants from a prehistoric cultural crossroad in western North Pontic steppe region remain understudied. This report presents results of the investigation of maternal genetic lineages of individuals buried in kurgans constructed during the Eneolithic-EBA transition in the western part of the North Pontic Region (NPR). Mitochondrial DNA (mtDNA) lineages from the interments belonging to the Eneolithic as well as the EBA cultures such as Yamna (Pit Grave), Catacomb and Babino (Mnogovalikovaya or KMK) were examined. In the 12 successfully haplotyped specimens, 75% of mtDNA lineages consisted of west Eurasian haplogroup U and its U4 and U5 sublineages. Furthermore, we identified a subgroup of east Eurasian haplogroup C in two representatives of the Yamna culture in one of the studied kurgans. Our results indicate the persistence of Mesolithic hunter-gatherer mtDNA lineages in western NPR through the EBA, as well as suggesting a mtDNA lineage continuum connecting the western NPR inhabitants of the Early Metal Ages to the North Pontic Neolithic population groups.