Do Dogs Come From East Asia Or Europe? New DNA Study Contradicts Old Beliefs
Evolutionary scientists are pretty sure they know how dogs evolved. On the other hand, there's still lots of debate on where they came from.
A study published this past May claimed that dogs originated from East Asia, while the latest study indicates their origin several thousand miles away in Europe. The controversy highlights the challenges involved in tracing an evolutionary map of species from their DNA.
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What is, however, beyond controversy is that wolves are the closest cousins of dogs. We know this without a doubt thanks to DNA and anatomy studies. Somewhere down the evolutionary line, wolves were domesticated when they transformed into a different behavior and body shape. They no longer hunted in packs but instead lingered around humans, using human settlements as a source of sustenance. From there they were bred further into different sub-species by humans trying to create pets and work animals with the best traits that the original dogs exhibited.
The clue to their transformed appearance lies in some fossils available. The oldest of these fossils (mostly from Europe) date as far back as 36,000 years, which is when the animals began looking like doggish wolves.
In the 1990s, new techniques to study the origin of dogs were developed, involving the sequencing of the genes of living dog breeds and wolves from diverse geographical locations to explore potential links. As a result, new stories — that differed from those told by the bones — began to emerge. Peter Savolainen (now at the Royal Institute of Technology, Sweden) conducted investigations that ultimately led to a 2002 study concluding that dogs came from East Asia. However, eight years later Robert Wayne and his team at the University of California, Los Angeles came to a different conclusion: dogs originated from the Middle East. On the face of it, these studies seem contradictory, but they could simply indicate that some breeds may have been independently domesticated.
In 2009, Dr. Savolainen and his team (on the basis of further DNA sequencing) not only reaffirmed East Asian origin of dogs but narrowed it down to South China. According to their studies, the Chinese dogs had the most wolf-like genomes. In their estimate, the Chinese wolves and village dogs split about 32,000 years ago with the implication that it was Chinese hunter-gatherers (and not farmers) who first domesticated first dogs at least 20,000 years before the onset of agriculture.
Dr. Wayne and his team, however, refute this theory by arguing that a dog may have wolf-like DNA possibly because of interbreeding. In addition, Wayne and his team are investigating the evidence through ancient DNA — that is, fragments of DNA from fossil samples. The first large scale comparisons of DNA samples from living and fossil dogs and wolves were reported on Thursday, in Science.
More specifically, they examined mitochondrial DNA that comes only from mothers. What they found completely rejects the Middle East or China origin of dogs. Instead, the living dogs, they argue, originated from ancient dogs or wolves from Europe.
However, the debate may yet continue; Savolainen told the New York Times that he thinks the study is flawed because it is geographically biased.
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