by Nicholas Wade (The New York Times)

Few people spend their honeymoon catching and drawing blood from village dogs up and down Africa. But Ryan and Corin Boyko, two anthropologists at the University of California, Davis, chose this way to collect valuable genetic data that is casting a new light on the domestication of dogs.

The two researchers wondered if the dogs carried a recently discovered gene that downsizes dogs from wolves and is found in all small dog breeds. Dr. Bustamante said the idea could be explored by collecting street dogs. Ryan and Corin Boyko collected 223 samples of village dog blood from Egypt, Uganda and Namibia. The small gene question has not yet been assessed, but their samples, reported in the current issue of the Proceedings of the National Academy of Sciences, have called into question a finding on the origin of dog domestication from wolves.

The origin is thought to be East Asia, based on a 2002 survey of both village dogs and breed dogs. But most of the village dogs in that survey came from East Asia, which could have tilted the outcome. The African village dogs turn out to have much the same amount of genetic diversity as those of East Asia. This is puzzling because the origin of a species is usually also the source of greatest genetic diversity.

The Boykos and Dr. Bustamante do not think dogs were domesticated in Africa — there are no wolves in Africa now, apart from the Ethiopian wolf — but they say the origin may not be East Asia. The issue is better addressed by looking just at village dogs, they think, and by excluding European breeds, which are mostly of recent origin.

They are now collecting samples from village dogs throughout the world in hope of tracing not just the place or places where dogs were first domesticated, but also the travels that dogs then took around the world with their masters. The lack of any sharp gradient of genetic diversity between East Asian and African village dogs could mean that once domesticated, dogs spread very quickly from their point of origin. Another explanation, Dr. Boyko said, is that they originated at some point halfway between the two regions, like in the Caucasus mountains.

The solution to the origin of the dog will come from sampling wolves throughout the world as well as village dogs, Dr. Wayne said. A genome-scanning chip, similar to those developed for studying the human genome, has been developed for dogs.


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