Modern dogs are often seen both as one of the earliest and best examples of domestication by humans. However, despite general consensus that modern dogs were domesticated from wild populations of grey wolf, the geographic region for the earliest domestication events still remains contentious. Arguments have been made for the earliest domestication of dogs around 13,000 ago in the Middle East or Eastern Asia; however, earliest fossil dogs in the archaeological record are from the period between 15,000-36,000 years ago, though some of the species assertions for these specimens remain debated.
A new study, recently published in Science, analysed the Mitochondrial DNA from 18 prehistoric canids and 20 modern wolves. Results indicate that all modern dogs and wolves fall within one of several well supported clades (A,B,C or D). In fact, the contested fossils from early Belgian sites represent one of the most deeply diverging groups study, which according to the authors, may represent an earlier, aborted domestication episode. Dog Clade A contains New World dogs and other species from Eastern Asia and are most closely related to a specimen from Switzerland c 32,100 years ago. Clade D contains two breeds of ancient wolf like canids similar to extant wolf populations with a common ancestor, from mDNA, of c 18,300 years ago. Clade C has its closest sister group with two ancient dog specimens from Germany between 16,000-24,000 years ago. The final Clade (B) has closest phylogenetic similarities to modern wolf populations from Sweden and the Ukraine c9200 years ago.
The association of all four clades with ancient European canids and modern dog populations suggests origins of dog domestication in Europe rather than the Middle East or East Asia. None of the modern wolf species from other purported centres of origin show close affinity with modern dog clades. Based on a Baysian analysis, the divergence times imply an origin for dog domestication between 18,800-32,100 years ago. These dates are, therefore, close to the Last Glacial Maxium and preceded the origins of agriculture and are firmly association with Upper Palaeolithic Hunter-Gatherers. The authors speculate that the origins of domestication could be related to help with hunting, scavenging of carcasses left by human groups and help with keeping other large carnivores away. The presence of aborted domestication attempts suggest that it was not a singular event but happened at different points and in different regions, perhaps for different reasons.
Full reference: Thalmann et al, 2013. Complete mitochondrial genomes of ancient Canids suggests European Origin of domestic dogs. Science, 342: 871. DOI: 10.1126/science.1243650