RETRIEVING HISTORY: Where did our best friend originate? Researchers are looking to DNA to dig up answers about where, when and why pooches became popular
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From precious pomeranians to mangy mutts, all domestic dogs (Canis familiaris) seem to be descended from the Eurasian gray wolf (Canis lupis). But what we still don't know is exactly when and where our best friends transformed from predators into partners. And such knowledge might help solve the long-disputed question of exactly why dogs were the first animal to be domesticated.

The dog genome (courtesy of a boxer named Tasha) was first decoded in 2005—and even before that researchers had been using genetic tools to track Fido's first home. Early research pointed toward east Asia as the locus of first taming after the discovery of high genetic diversity and other key markers in dog populations from various villages there.

Some investigators, however, have since pointed out that the genetic search sampled more east Asian village dogs, neglecting similar pups roaming other villages around the globe. That's where the Village Dog Genetic Diversity Project at Cornell University comes in. Starting with a recent genetic analysis of dogs in African villages, the Cornell group hopes ultimately to create a detailed DNA-based map of canine ancestry worldwide, which in turn should fetch a new understanding of the ancient humans who took them in.

One part of that new insight appeared earlier this month in the Proceedings of the National Academy of Sciences (PNAS), in a study that calls into question the assumption of dogs' east Asian origin. A team led by Adam Boyko, a researcher at Cornell's Carlos D. Bustamante Lab, sampled 318 village dogs in Africa (as well as hundreds of dogs from North America and Europe for comparison) and discovered that the high genetic diversity of canines there resembles that found in east Asia. "We found almost without exception they're descended from different ancestral populations," Boyko says of the village dogs sampled in Africa. That means they may have been there just as long as others had been in east Asia.

Researchers have also yet to figure out when people first began raising dogs. The going theory is that dogs were domesticated somewhere between 15,000 and 40,000 years ago. But, Boyko explains, genetic testing has not gone deep enough to come up with a more refined date.

To try to track down some more clues, field crews have fanned out around the globe this summer to test village dogs in Vietnam, New Guinea, Malaysia and other locations in Eurasia. "That's a big place, and we need to get more data," says Boyko, who owns a mixed-breed dog himself (which, after some genetic testing, turned out to be part chow—one of the more ancient breeds).

Of course, scrappy village dogs aren't often the focus of heartfelt conservation efforts, and some even face active elimination programs. But these pups also have challenges from newly arrived European-descent dogs, which threaten to make a splash in the regional gene pool. "It is unclear the degree to which older populations will be able to maintain their genetic identity and persist in the face of modernity," Boyko and his co-authors wrote in the PNAS paper. So time is of the essence in digging up a solid answer about doggie descent.