Interestingly, when compared to extant wolf and dog sequences available from GenBank, all seven haplotypes found in the Pleistocene samples were found to be unique and not described to date. This result is remarkable when considering the large number of wolf (~160) and particularly dog sequences (> 1,000 from almost all breeds known today) available in Genbank.
This may be consistent with selection affecting mtDNA since the Paleolithic, with recent dogs and wolves being descended from a small subset of the Paleolithic mtDNA diversity. Also from the paper:
Compared to wolves, ancient dogs exhibit a shorter and broader snout (Lawrence, 1967; Olsen, 1985; Sablin and Khlopachev, 2002). All Palaeolithic dogs in our study conform to this pattern.
As demonstrated above, the Palaeolithic dogs in our data set are very uniform in their skull shape. Even the Goyet dog, with an age of c. 31,700 BP, is not intermediate in form between the fossil wolves and the prehistoric dogs, but conforms to the configuration of the other Palaeolithic dogs, which are approximately 18,000 years younger. The abrupt appearance of a dog, much older than the Eliseevich I dogs, the oldest recognized dogs so far, suggest that the domestication process must have been quite rapid (cf. Crockford, 2000a).
Was the dog the very first animal to be domesticated by man, truly his "oldest friend"? I would not be surprised if our relationship with dogs stretches even further to the past. Dogs are such useful helpers in a hunting culture, that their value must have been recognized from early on.
Journal of Archaeological Science doi:10.1016/j.jas.2008.09.033
Fossil dogs and wolves from Palaeolithic sites in Belgium, the Ukraine and Russia: osteometry, ancient DNA and stable isotopes
Mietje Germonpré et al.
Using multivariate techniques, several skulls of fossil large canids from sites in Belgium, Ukraine and Russia were examined to look for possible evidence of the presence of Palaeolithic dogs. Reference groups constituted of prehistoric dogs, and recent wolves and dogs. The fossil large canid from Goyet (Belgium), dated at c. 31,700 BP is clearly different from the recent wolves, resembling most closely the prehistoric dogs. Thus it is identified as a Palaeolithic dog, suggesting that dog domestication had already started during the Aurignacian. The Epigravettian Mezin 5490 (Russia) and Mezhirich (Ukraine) skulls are also identified as being Palaeolithic dogs. Select Belgian specimens were analysed for mtDNA and stable isotopes. All fossil samples yielded unique DNA sequences, indicating that the ancient Belgian large canids carried a substantial amount of genetic diversity. Furthermore, there is little evidence for phylogeographic structure in the Pleistocene large canids, as they do not form a homogenous genetic group. Although considerable variation occurs in the fossil canid isotope signatures between sites, the Belgian fossil large canids preyed in general on horse and large bovids.