Modern humans originated in Africa, and now it looks like man's best friend first emerged there too.
An extensive genetic study on the ancestry of African village dogs points to a Eurasian — possibly North African — origin for the domestication of dogs.
Prior research concluded that dogs likely originated in East Asia. However, this latest study, the most thorough investigation ever on the ancestry of African village dogs, indicates otherwise.
"Village" dogs are local, semi-feral dogs that cluster around human settlements in much of the world.
"I think our results cast some doubt on the hypothesis of an East Asian origin for dog domestication that was put forward based on previous mitochondrial DNA genetic research," lead author Adam Boyko told Discovery News.
Boyko, a research associate in the Department of Biological Statistics and Computational Biology at Cornell University, and his colleagues looked at three genetic markers for 318 village dogs from seven regions in Egypt, Uganda and Namibia. The scientists performed the same DNA analysis on a number of putatively African dog breeds, as well as on Puerto Rican street dogs and mixed breed dogs from the United States.
The scientists determined genetic diversity was just as high for the African dogs as it was for the East Asian village dogs that were the focus of the earlier research.
"Species tend to show the highest genetic diversity near their place of origin," said Boyko. He explained that this is because the species have "been there longer and therefore have had more time to accumulate diversity, and because as a species expands its range by colonizing a new region, it usually does so with a relatively small band of individuals carrying just a subset of the genetic diversity found in the ancestral population."Seven signs of evolution in action
Humans might have then first domesticated dogs from wolves in Africa, with Egypt being one possibility, since wolves are native to that region. Many existing wild species of canid, such as the Egyptian jackal, popularly featured in ancient Egyptian art, are now critically endangered.
The new study, published in the latest issue of the Proceedings of the National Academy of Sciences, also found that some so-called "African" dog breeds are not really native to Africa. These include Pharaoh hounds and Rhodesian ridgebacks, which turned out to not have much indigenous African ancestry.
On the other hand, "Basenjis are clearly an indigenous sub-Saharan breed, and Afghan hounds and Salukis appear to be indigenous to North Africa or the Middle East," Boyko said.
The pattern seems to be that if a region was colonized or otherwise settled by Europeans, dogs of that area now tend to be less indigenous. Dogs in central Namibia, for example, "looked nearly identical genetically to dogs you would find on the streets of Puerto Rico or in animal shelters in the U.S., a pretty clear indication that these are mixes of various modern breeds."
Robert Wayne, an expert on wolves and dog domestication and a professor in the Department of Ecology and Evolutionary Biology at UCLA, told Discovery News that he supports the new findings.
"It's clear dogs did not originate in sub-Saharan Africa, since wolves are not native to that area," asserts Wayne. However, he agrees that Eurasia is the more likely overall place where dogs were first domesticated, with Egypt being a possibility.
Both Wayne and Boyko hope future genetic research on canines will continue to shed light on the origins of indigenous dog populations to better confirm and pinpoint exactly where the domestication of dogs first happened.
© 2012 Discovery Channel