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Scottie Westfall

Scottie Westfall writes about dogs, nature, science and history at retrieverman.wordpress.com.

Good Dog: Studies & Research
Study Places Origin of Domestic Dog in Middle East

A new study of the genomes of domestic dogs and wolf populations has determined that the domestic dog most likely originated in the Middle East. The finding strongly contradicts earlier mitochondrial DNA studies that put the origins of the domestication in East Asia. In comparing the various genomes of different populations of wolves and dogs, researchers at the University of California, Los Angeles, concluded that dog genomes and Middle Eastern wolf genomes contain the greatest similarity.

The research team, led by Dr. Robert K. Wayne and Bridgett M. vonHoldt, used a genome-wide methodology to determine which populations of wolves were most closely related to dogs. SNP or “snip” chips (devices similar to computer chips than can “read” the DNA down to a single nucleotide polymorphism), looked at 48,000 different locations in the dog genome. SNP chips have been used to scan humans for susceptibility to disease, such as cancer predisposition. In this study, the chips mark regions of common variation within the DNA, allowing researchers to make more accurate comparisons across populations.

It turns out that dogs have more similarities at these 48,000 different locations with Middle Eastern wolves than with other populations of wolves. The findings strongly suggest that today’s domestic dog descends from ancestors in the Middle East.

The original mitochondrial DNA studies looked at only one part of the genome, which is inherited from the female ancestors. Such studies found greater variance in the mitochondrial DNA of East Asian dogs, and since organisms have greater genetic variation at their point of origin, it was then thought that dogs were originally domesticated in Southern China. Because mitochondrial DNA is but a small part of the genome, inferences gleaned from its study may not be as valid as those from a genome-wide study.

Now we know that Middle Eastern wolves likely were among the first populations of wolf to encounter humans; thus it is from these populations that our oldest friend evolved. Researchers also looked for signatures of selection in the genes, and one of the notable genes identified has a human counterpart — implicated in Williams syndrome — which is expressed as extreme friendliness disorder in humans.

Culture: Reviews
The Wolf in the Parlor
Henry Holt, 304 pp., 2009; $25

In The Wolf in the Parlor, science journalist Jon Franklin uses the narrative skills that helped him win two Pulitzers to posit a theory about the origins of the domestic dog that seems to be based more upon speculation than upon science.

Franklin’s compelling narrative can certainly absorb the reader. The storyline reads like a mystery novel, peppered with vignettes about Charlie, Franklin’s black Standard Poodle, as well as anecdotes about various scientists and others who have explored the origins of the domestic dog—for example, the story of archeologist Stanley Olsen’s Shepherd/Malamute cross, Nubie, whose epilepsy controlled Olsen’s daily schedule and even his professional travel plans. Each of these stories drives a narrative that gradually reveals Franklin’s over-arching theory, which is not a complicated one.

At least 50,000 years ago, a population of wolves followed bands of huntergatherers. These wolves were physically the same as the wolves who were not following the bands, but Franklin contends that their brains were changing—that they were losing the innate predatory motor patterns that wolves had evolved to kill large prey. Then, 12,000 years ago, Franklin argues, the follower wolves lost 20 percent of their brain size, and humans lost 5 to 10 percent of theirs. According to Franklin, this reduction in brain size is indicative of a new symbiotic relationship, one based upon what he calls a “neural symbiosis.” In this relationship, each species ceded to the other important neural functions. Dogs gave up their ability to make complex plans, while people lost their ability to experience raw emotions. Once humans were no longer controlled so strongly by emotion, they were able to focus on developing the technology that led to our current dominance as a species.

Though Franklin is not the first to write about the co-evolution of humans and dogs, the lack of citations to other literature, peer-reviewed or otherwise, implies that he came up with this theory on his own. The closest he comes to citing an expert in the field is a passing reference to the work of biologist Raymond Coppinger, who contends that dogs evolved from wolves who learned to scavenge off humans once humans began engaging in small-scale agriculture and living in relatively permanent villages. Agriculture likely began 12,000 years ago, which is exactly the point at which both Coppinger and Franklin believe that the first domestic dogs appeared. Moreover, Franklin provides no bibliography to assist the reader in finding where his theory fits within the scientific literature.

At face value, Franklin’s theory sounds plausible, but it simply does not square with what scientists have discovered about the evolution of domestic dogs and of the human brain. At the end of the Pleistocene, human brains became smaller, but that smaller brain was consistent with a general reduction in body size and clearly had nothing to do with its function. Furthermore, dogs were most likely domesticated more than 12,000 years ago. The oldest accepted dog remains date to 14,000 years ago, and some genetic studies suggest that dogs have been living with people for more than 100,000 years. Because Franklin’s theories do not fit with this scientific evidence, the book comes across as nothing more than a good story.