The search for the origin of the domesticated dog has been a long process and full of controversy. We all have heard how dogs were domesticated from wolves, but knowing when and where is a bit of a mystery. “New Finding Puts Origins of Dogs in Middle East” by Nicholas Wade reports on a new study that has yet another theory on the origin of dog domestication- the Middle East.
Bridgett M. vonHoldt and Robert K. Wayne of UCLA led a team that analyzed a large collection of wolf and dog DNA from around the world. Using two dog genomes previously sequenced (a poodle and a boxer) they developed a dog SNP chip that was used to scan for variable sites in the DNA of a variety of dogs and wolves and cluster them into groups of who is most related to who. Not only did this allow them to place the origin of the domesticated dog in the Middle East, but also showed that dogs with common functions (such as herding dogs and scent hounds) are closely related- showing that these functions are not an example of convergent evolution but that breeds with a common function are closely related.
This team concluded that dogs were domesticated in the Middle East, and later spread to East Asia (where previous studies have put the origin of domesticated dogs). In Asia, some of the dogs bred with local wolves, part of the reason the genetic evidence is so convoluted. The team also used their SNP chips to scan for areas that showed signatures of selection. There is evidence supporting that the dogs lovable personality and their unique ability to “read” human expression were both selected (whether naturally or artificially) in the dog domestication process.
All theories on the origin of a species must be checked with archeological evidence, especially since most DNA samples taken are from modern dogs and wolves and is only a reflection of what was. A Middle Eastern origin fits the archeological evidence better than the other theories presented. This study puts the origin of a domesticated species, dogs, at the same place of domestication of many other plants and animals. According to this study, dogs were domesticated 15,000 years ago- a time when hunter gathers were converting to more stationary societies. Dogs may not only be our best friends, but what allowed us to settle and grow into what we are today.
P.S: Check out the family tree from this article: http://www.nytimes.com/2010/03/18/science/18dogs.html?scp=6&sq=Dog+DNA&st=nyt
P.S.S. If you search for the study this paper was based on, you can get an even better tree!
Reference:
Wade, Nicholas. "New Finding Puts Origins of Dogs in Middle East." New York Times 17 March 2010: Web. 16 May 2010.
Original Article:
vonHoldt, Bridgett M., John P. Pollinger, Kirk E. Lohmueller, Eunjung Han , and others. "Genome-wide SNP and haplotype analyses reveal a rich history underlying dog domestication." NATURE 464.8 April 2010: 898-903. Web. 28 April 2010.
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I read a few months ago that dogs were domesticated in China for human consumption. I feel much better knowing that the previous data was flawed.
ReplyDeleteCanine domestication can be such a controversial issue; how Europe/U.S. define a "domesticated dog" skeleton is often different from China's definition.
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