María Dolores Garralda

Paleogenomic Evidence for Multi-generational Mixing between Neolithic Farmers and Mesolithic Hunter-Gatherers in the Lower Danube Basin

Summary The transition from hunting and gathering to farming involved profound cultural and technological changes. In Western and Central Europe, these changes occurred rapidly and synchronously after the arrival of early farmers of Anatolian origin [1, 2, 3], who largely replaced the local Mesolithic hunter-gatherers [1, 4, 5, 6]. Further east, in the Baltic region, the transition was gradual, with little or no genetic input from incoming farmers [7]. Here we use ancient DNA to investigate the relationship between hunter-gatherers and farmers in the Lower Danube basin, a geographically intermediate area that is characterized by a rapid Neolithic transition but also by the presence of archaeological evidence that points to cultural exchange, and thus possible admixture, between hunter-gatherers and farmers. We recovered four human paleogenomes (1.1× to 4.1× coverage) from Romania spanning a time transect between 8.8 thousand years ago (kya) and 5.4 kya and supplemented them with two Mesolithic genomes (1.7× and 5.3×) from Spain to provide further context on the genetic background of Mesolithic Europe. Our results show major Western hunter-gatherer (WHG) ancestry in a Romanian Eneolithic sample with a minor, but sizeable, contribution from Anatolian farmers, suggesting multiple admixture events between hunter-gatherers and farmers. Dietary stable-isotope analysis of this sample suggests a mixed terrestrial/aquatic diet. Our results provide support for complex interactions among hunter-gatherers and farmers in the Danube basin, demonstrating that in some regions, demic and cultural diffusion were not mutually exclusive, but merely the ends of a continuum for the process of Neolithization.

Neanderthal Geographical and Chronological Variation

There is now a reasonable sample of human fossils from the European Middle and beginning Upper Pleistocene. However, our ability to fully understand their evolutionary relationships and the part they played in the ancestry of the Neanderthals remains uncertain. Part of the reason for this is the fragmentary nature of many of the finds, with fossils preserving different anatomical features, making detailed anatomical comparisons difficult or impossible. An equally important obstacle to our knowledge of this part of human biological history are the often difficult to interpret and conflicting dates that have been obtained for many of these finds. Nevertheless, a number of fossils, including the sizable sample from the Sima de los Huesos, testify to the European ancestry of the Neanderthals, although the possible presence and gen-flow from groups of Asian or maybe African origins cannot be excluded.