Evidence for Early European Neolithic Dog Dispersal: New Data on Southeastern European Subfossil Dogs from the Prehistoric and Antiquity Ages

Abstract

The history of dog domestication is still under debate, but it is doubtless the process of an ancient partnership between dogs (Canis familiaris) and humans. Although data on ancient DNA for dog diversity are still incomplete, it is clear that several regional dog populations had 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 populations. In this study, we present for the first time mitochondrial data of ancient dog remains from the Early Neolithic (8000 years before present (BP)) to Late Antiquity (up to 3th century AD) from southeastern Europe (the Balkans). A total of 16 samples were analyzed, using the mitochondrial D-loop region (HVR1). The results show the presence of A (70%) and B (25%) clades throughout the Early and Late Neolithic 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 showed a similarity of the ancient Bulgarian dogs to Italian (A, B, and C clades) and Iberian (clades A and C) dogs’ populations. A clear border can be seen between southern European genetic dog structure, on the one hand, and on the other hand, central-western (clade C), eastern (clade D) and northern Europe (clades A and C). This corresponds to genetic data for European humans during the same period, without admixture between dog populations. Also, our data have shown 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.

Population Dynamics in Italian Canids between the Late Pleistocene and Bronze Age

“…Those results, combined with the findings of Pires et al [33] on the occurrence of Late Pleistocene wolves and Mesolithic dog carrying a Hg A canine haplotype in another glacial refugium, the Iberian Peninsula, stimulate interest towards these areas and their role in the dog domestication issue as a whole. Neolithic Bulgarian dogs in the Balkan Peninsula [6] with high percentages of Hg A and B support the findings of Pires et al [33]. These results are of particular interest because, according to previous data [36], Hg A-dogs were only estimated to have arrived in Europe during the Bronze Age.…”

“…Electropherograms were analyzed and edited using the software FinchTV (Geospiza Inc., Seattle, WA, USA) and BioEdit [49,50]. Sequences were aligned using the dog mtDNA sequences NC_002008 and EU789787 as reference, following the steps of previously published papers [6,9,51,52]. Haplogroup assignments were determined through a phylogenetic analysis by creating UPGMA trees in MEGA X (Penn State University, PA, USA) [53], using reference samples with well-defined dog matrilines, available from previous studies [54,55].…”

“…In order to investigate haplogroup patterns and dynamics, ggplot2 [58], a data visualization package in R [59], was used to create a graphical representation of the proportions of haplogroup through time. The plot included the ancient Eurasian dogs from this study and those available in the literature [6,9,10,13,29,31,33,34,52,[60][61][62][63][64] (Table S1).…”

“…The origin of dogs dates to the ancient coevolution and mutualism established between Paleolithic humans and wolves [3,[6][7][8]. However, details such as the time and place of dog domestication, the motivation behind this process, and how it occurred are yet to be clarified [2,6,9,10]. Uncertainty regarding dog domestication is mainly due to a lack of available data, and those obtained by key morphological characters that were not fixed during the initial phases of the domestication process.…”

Complete Range of the Universal mtDNA Gene Pool and High Genetic Diversity in the Thai Dog Population

“…A study of mtDNA in European pre-Neolithic dogs found all 15 investigated samples (100%) to have haplotypes belonging to haplogroup C [19]. In contrast, a study of 16 Neolithic dogs from Southeast Europe showed "normal" frequencies of haplogroup A and B (75% and 20%, respectively) and no haplotype from haplogroup C [20]. Our study similarly shows that today's European dogs carry all three major haplogroups, A, B and C, with only 8% carrying haplotype C (Table 1).…”