| 5 September 2009
Dogs first tamed in China - To be food?
Wolves were domesticated no more than 16,300 years ago in southern China, a new genetic analysis suggests—and it's possible the canines were tamed to be livestock, not pets, the study author speculates. "In this region, even today, eating dog is a big cultural thing," noted study co-author Peter Savolainen, a biologist at the Royal Institute of Technology in Stockholm, Sweden. "And you can also see in the historical records as far back as you can go that eating dogs has been very common in East Asia. Therefore, you have to think of the possibility that this was one of the reasons for domesticating dogs."
The new work, bolsters the long-held theory that dogs first became 'man's best friend' in East Asia. That notion came under fire last month, based on a DNA analysis of so-called village dogs in Africa. The highest level of genetic diversity in modern dogs should exist in the region where the animals first came under human control. But the August study found that African village dogs have a similar amount of genetic diversity as those in East Asia, calling into question the origins of dog domestication.
For the new work, Savolainen and colleagues analyzed the entire mitochondrial genome—DNA passed down only from the mother—of 169 dogs, as well as portions of the genomes from 1,543 dogs from across Europe, the Middle East, and Asia. These dogs all share at least 80 percent of their DNA, the team found. The animals' genetic diversity increased the farther east the scientists looked. The greatest diversity was found in a region south of the Yangtze River in China. According to Savolainen, the data make it 'totally clear' that genetic variation in East Asian dogs is much higher than anywhere else in the world.
The analysis also suggests that wolves were domesticated from several hundred individuals sometime between 5,400 and 16,300 years ago. This is around the time Asian hunter-gatherers were adopting a more settled agrarian lifestyle, which is part of what makes Savolainen think the canines might have been kept as food. Adam Boyko, a biologist at Cornell University in New York and co-author of the August study, agrees that the new work shows greater genetic diversity in East Asia than Africa. But Boyko said he would like to see more genetic evidence before he calls the finding proof of domestication.
Source: National Geographic News (4 September 2009)
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