The study uses the principle of "greatest diversity" in determining the origin of the domesticated dog. The idea again is that dogs migrating away from the place of origin carry some but not all of the genetic types found within the species. Therefore, nearly all the dogs outside of "ASY," which stands for "Asia south of the Yangtze," i.,e. South China and Southeast Asia, originated from a subset of the total haplogroups found in ASY. And there were many unique haplotypes found only in ASY. Only in this region were all 10 major haplogroups found and this number decreases as one moves further away through Eurasia with the lowest total of four haplogroups found in Europe.
Interestingly of all the geographic areas tested, the Southeast Asian sample had the highest genetic diversity at 0.9526 followed by South China at 0.9486. The exact samples from these regions are:
Guangdong (n=14), Guangxi (n=35), Hunan (n=54), Guizhou (n=57), Jiangxi (n=46), Yunnan (n=75)
Thailand (n=41), Vietnam (n=11), Cambodia (n=7)
What is apparent is that with the exception of northern Yunnan, the wolf is not present in any of these areas in modern times. At one time, it was assumed that the wolf must have extended over all this region and further because of the existence of the dingo in Australia.
The dingo was considered a wild dog, but modern research led by one of the supporting authors of the current study -- P. Savolainen -- suggests that the dingo is actually a descendant of the domesticated dog.
However, the dingo's behavior is very much like a wild dog suggesting that possibly it represents a mixture of wild and domesticated dogs. Multi-generational feral dogs generally depend on human settlement where they scavenge garbage heaps, beg for scraps, and, in some cases, prey on livestock. Most dingos, though, lived totally independent of human populations when they were first studied by Europeans.
Now the existence of similar "wild" dingos in Thailand and Sulawesi, and dingo-like feral dogs throughout much of Southeast Asia, is suggestive. If the original domesticated dog was often feral, as is the case in modern Southeast Asia, then interbreeding with wild wolves could have been commonplace.
Although wolf packs will attack dogs and other wolves that are strangers to the pack, when individuals break off from a pack to mate, they are much friendlier. It is known that wolves, for example, in the Americas will even sometimes mate with different species like the coyote.
So during the early domestication period, large packs of feral or semi-domesticated dogs may have bred with the wild dog, or wolf population. Eventually these mixed types would have developed into the wild-ranging dingo, or the wild populations wold merge with feral dog stocks. This could explain why the pure wolf is no longer found in Southeast Asia or most of South China.
Now when the domesticated dog moved out of ASY, it would have encountered different situations especially among pastoral peoples. These groups raise herds of free-ranging livestock, which are very vulnerable to predation by feral dogs. Thus, humans in these cultures would have taken greater measures to cull feral dog populations. Also, they probably trained dogs at an early age to guard herds and flocks against wolves, which would have helped prevent interbreeding between wolf and dog. Across many of the geographical areas bordering ASY, feral dog populations cannot survive to the same extent as in ASY. In these areas, dogs become more dependent on humans and the number of feral dogs decreases.
The authors suggest that the domesticated dog spread with agriculture, however, I think the archaeological record clearly contradicts this assertion. Dogs were diffused during the Mesolithic period, possibly when humans were first engaging in pastoralism, if we accept that the latter practice arose among hunter-gatherers. I wonder if there is any influence on the idea of dogs diffusing together with agriculture, that comes from the Chinese tradition of Panhu, the Dog-Man-God, which is sometimes interpreted as referring to the spread of the domesticated dog. I give my explanation of this myth and its relation to the spread of rice agriculture here and here.
Paul Kekai Manansala
Mol Biol Evol. 2009 Sep 1. [Epub ahead of print]
mtDNA Data Indicates a Single Origin for Dogs South of Yangtze River, less than 16,300 Years Ago, from Numerous Wolves.
Related linksDog as deity, ancestor and royal animal
Fleming, Peter; Laurie Corbett, Robert Harden, Peter Thomson (2001). Managing the Impacts of Dingoes and Other Wild Dogs. Commonwealth of Australia: Bureau of Rural Sciences.
Dingos (photo from Wikipedia)