Humans have lived with dogs for thousands of years but there are some things – like where did dogs come from? – that still remain a mystery.
Scientists have been consistent is stating that gray wolves are dogs’ ancestors. Researchers have also suggested that dogs’ origins can be traced to Europe, the Near East, Siberia and South China.
But according a recent and large study of dogs from around the world, Central Asia is the newest and best candidate.
Laura M. Shannon and Adam R. Boyko at Cornell University, and an international group of other scientists, have studied all kinds of dogs – from purebred dogs to street or village dogs who make up about 75 percent of the world’s one billion dogs.
According to Dr. Boyko, Dr. Shannon analyzed three different kinds of DNA. This was the first time this has was done on such a large and diverse scale. She analyzed more than 4,500 dogs of 161 breeds and 549 village dogs from 38 countries.
The diversity of dogs involved in the study allowed the researchers to determine which geographic groups of modern dogs were closest to ancestral populations genetically. This led to the finding that Central Asia is where dogs originated.
The team analyzed DNA from all the chromosomes in the cell nucleus, from the Y chromosome specifically, found only in males, and from mitochondria, cellular energy machines outside the nucleus that are inherited from the mother.
Dr. Boyko said, the findings pointed to Central Asia, including Mongolia and Nepal, as the place where “all the dogs alive today” come from. He added that the data did not allow precise dating of the origin, but showed that it occurred at least 15,000 years ago.
The research group’s findings were published in the journal Proceedings of the National Academy of Sciences on Monday.
Greger Larson of Oxford University, who is leading an international effort to analyze ancient DNA from fossilized bones, said he was impressed by the scope of the study.
“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,” he said.
Dr. Larson, who is not involved in the study, also praised the sampling of different kinds of DNA and the analytic methods used in the research.
But in the world of dog studies, very little is definitive. Dr. Boyko said the most recent common ancestor of today’s dogs lived in Central Asia although he cannot rule out the possibility that some dogs could have been domesticated elsewhere and died out. There is also the possibility that dogs domesticated elsewhere went to Central Asia from somewhere else and then diversified into all the canines alive today, he said.
Dr. Larson said he thought the Central Asia finding required further testing and that he suspected that the origins of modern dogs were “extremely messy”. He adds that no amount of sampling of living populations would ever be definitive but a combination of studies of modern and ancient DNA was necessary.
“The great thing about working with dogs is that if you show up with food you don’t usually have trouble recruiting subjects. Usually,” said Dr. Boyko. “We showed up in Puerto Rico at a fishing village and the dogs turned up their noses at roast beef sandwiches. They were used to eating fish entrails.”
Source: NY Times