By Steve Gorman, March 29, 2010
LOS ANGELES (Reuters) - From French poodles to German shepherds, domestic dogs likely trace most of their ancestry to the Middle East, as opposed to East Asian origins suggested by previous research, a genetic study reported on Wednesday.
The findings, published in the online edition of the scientific journal Nature, support an archaeological record that closely links the domestication of dogs in the Middle East with the rise of human civilization there, scientists said.
"It's significant because this is where civilization developed, and dogs were part of that," said Robert Wayne, professor of evolutionary biology at the University of California, Los Angeles, and a senior author of the study.
The region, often referred to as the Fertile Crescent, includes much of modern-day Iraq, Syria, Lebanon and Jordan --"the same area where domestic cats and many of our livestock originated, and where agriculture first developed," he said.
The study is based on genetic comparisons between more than 900 dogs representing 85 breeds and over 200 wild gray wolves -- the closest living wild relative of dogs -- from around the globe, including North America, Europe, East Asia and the Middle East.
In the most extensive such analysis to date, scientists used molecular genetic techniques to examine more than 48,000 markers from across the entire genome -- or DNA sequence -- from each of the animals included in the study.
What they discovered was the vast majority of dogs share more unique genetic markers with gray wolves from the Mideast than with other wolf populations. A kinship to European wolves also was found, but to a lesser extent, Wayne said.
NUISANCE OR COMPANION?
One notable exception was the finding of a close genetic link between a small number of East Asian dog breeds and wolves from China, suggesting some intermingling between the two.
But the new research contradicts an earlier genetic study suggesting a close ancestry of all dogs to wolves from East Asia and China. That analysis was based on comparisons between a single, small DNA sequence taken from mitochondria -- tiny structures outside the nucleus of living cells that carry their own genes -- rather markers from entire genomes.
The newer research was far more comprehensive and "is much more consistent with the archaeological record," Wayne said.
"We know that dogs from the Middle East were closely associated with humans because they were found in human burial sites" there, he said. In one famous example, the remains of a puppy were found curled up in the arms of a human skeleton.
But the earliest bond between people and "man's best friend" was probably more often a love-hate relationship that persists in parts of the world to this day, and helps explain a cultural ambivalence towards dogs in the very region where they likely originated.
The archaeological record of dogs dates back 31,000 years to the remains of a Great Dane-like specimen found in Belgium. The first Mideast dogs appeared 12,000 to 13,000 years ago.
Although agriculture and animal husbandry go hand in hand, the first people to domesticate dogs from wild wolves probably were nomadic hunter-gatherers, who were followed at a distance by canine interlopers in search of scraps.
That relationship likely matured over thousands of years "to the point where these proto-dogs were living in close proximity with humans," and were often more of a nuisance than they were companions, Wayne said.
"Eventually dogs provided protection, an early warning system, maybe even helped out with the hunt, and then eventually, even closer in, provided companionship," he said.
While some dog breeds have ancient histories, 80 percent are modern varieties that have evolved since the explosion in dog breeding during the Victorian era, Wayne said.
(Editing by Dan Whitcomb and Vicki Allen)
