An in-depth study led by Cornell University researcher Adam Bokyo into the origin of dogs has concluded that man’s best friend was first domesticated in Central Asia, reports the BBC.
This detailed genetic survey analyzed the DNA of 4,676 purebred dogs from a range of 161 breeds, and 549 “village dogs” from 38 countries around the world.
Street or village dogs – the free ranging scavengers that have a loose association with humans and live around human settlements – make up about 75 percent of the planet’s total one billion strong dog population.
The wide array of dogs that we know and love today are all descended from wolves that were gradually tamed and then assimilated over time into human hunting groups.
On this point, there is a high degree of consensus among scientists, but the question of where this change in dog domestication took place is still very much a live one.
Previous research has suggested a variety of locations as potential areas of primary domestication, tracing dog origins to Europe, the Near East, Siberia, and South China.
But no study has proved conclusive.
It is possible dog domestication events could have occurred in multiple locations, but no research has uncovered evidence that confirms that theory.
This new study breaks ground in that it argues the process of dog domestication began near Mongolia or Nepal, and indeed, asserts that this is where “all the dogs alive today” come from. But the study could not determine any precise dating of when the domestication took place, but indicated that it occurred at least 15,000 years ago.
“The fact that we looked at so many village dogs from so many different regions, we were able to narrow in on the patterns of diversity in these indigenous dogsWe looked exclusively to see if there was evidence of multiple domestication events. And like every other group that’s looked for that, we found no evidence of it. It looks like there’s a single origin, although there are clearly situations where there has been a little bit of gene flow between wolves and dogs post-domestication.”
Dr. Boyko and his team looked closely at genetic markers – genes located close to one another on chromosomes – and the evidence garnered pointed to a common dog ancestry in Central Asia.
They analyzed DNA from all the chromosomes in the cell nucleus –from the Y chromosome specifically, found only in males– and from mitochondria, the cellular energy machines outside the nucleus that are inherited from the mother, reports the New York Times.
“There’s no doubt they were hanging around [hunting] camps and becoming gradually more attuned to human life. The question is what was the first step for why that was happening; It’s tempting to ask whether it was something to do with hunting. I think it’s clear that scavenging by wolves on human kills [of large mammals] could have been the driving force.They hitched themselves to us, which was a pretty good gamble as it turned out because there are about a billion dogs in the world today and probably not even 10 million wolves.”
The study does not eliminate the possibility dogs may have been domesticated before they were in Central Asia and then died out, or that dogs domesticated elsewhere could have gone to Central Asia from somewhere else and then diversified into all the dogs alive today.
Greger Larson from Oxford University is leading an international effort to analyze ancient DNA from fossilized bones. He was impressed by the depth of the study, telling the New York Times, “It’s really great to see not just the sheer number of street dogs, but also the geographic breadth and the number of remote locations where the dogs were sampled.”
The findings of this study were published on Monday in Proceedings of the National Academy of Sciences.
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