Evidence for Early European Neolithic Dog Dispersal: New Data on South-Eastern European subfossil dogs from Prehistory and Antiquity Ages

Objectives The history of dog domestication is still under debate, but doubtlessly, it is a process of an ancient partnership between dogs (Canis familiaris) and humans. Although data on ancient DNA dog diversity are scarce, it is clear that several regional dog populations had been formed in Eurasia up to the Holocene. During the Neolithic Revolution and the transition from hunter-gatherer to farmer societies, followed by civilization changes in the Antiquity period, the dog population structure also changed. This process was due to replacement with newly formed dog breeds. Methods In this study we have presented for the first time mitochondrial data about South-Eastern Europe (the Balkans) ancient dog remains from the Early Neolithic (8 000 years BP) to the Late Antiquity ages (up to 3th century AD). A total of 25 samples were analyzed using the mitochondrial D-loop region (HVR1). Results The results have shown the presence of A (70%) and B (25%) clades throughout the whole investigated period. In order to clarify the position of our results within the ancient dog population in Eneolithic Eurasia, we performed phylogenetic analysis with the available genetic data sets. This data revealed a similarity of the Bulgarian dogs’ structure to that of ancient Italian dogs (A, B, and C clades), which suggests a new prehistoric and historic Mediterranean dog population. A clear border can be seen between South-European genetic dog structure, on the one hand, and, on the other hand, Central-West (clade C), East (clade D) and North Europe (clades A and C). This corresponds to genetic data for European humans during the same period without admixture between dog populations. Conclusions Our data have shown for the first time the presence of clade B in ancient Eurasia. This is not unexpected as the B haplogroup is widely distributed in extant Balkan dogs and wolves. The presence of this clade both in dogs and in wolves on the Balkans may be explained with hybridization events before the Neolithic period. The spreading of this clade across Europe together with the A clade is related to the possible dissemination of newly formed dog breeds from Ancient Greece, Thrace and the Roman Empire.