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Posts Tagged ‘Adam Boyko’

African village dogs are just as genetically diverse as those in East Asia, and they have been found to be closely related to Middle Eastern wolves.

From National Geographic:

Labradors may be the most popular breed of dog, but the most populous kind is no breed at all. That distinction goes to the humble village dog scratching out a semiwild living in and around human settlements.

While a postdoc at Cornell University a few years ago, Adam Boyko became curious about the little-studied village vagrants. Though dogs were first domesticated 20,000 to 15,000 years ago, most breeds go back only a few hundred years. Perhaps village dog DNA might shed light on the long, early history of domestication, when canines were hanging around humans yet not under our domain. But how to get samples?

As it happened, around the same time Boyko’s brother Ryan had married, and he and wife Corin were looking for a cheap honeymoon off the beaten track. The three Boykos decided to merge their two quests. Adam—now at Cornell’s College of Veterinary Medicine—­obtained a grant, then enlisted Ryan and Corin to spend their honeymoon traveling around Egypt, Uganda, and Namibia, befriending villagers and local vets. They collected DNA from more than 300 village dogs.

When the samples were analyzed, most of the village dogs turned out to be as closely related to wolves as they were to fully domesticated dogs. Rather than being mixed-breed mutts that had gone feral in historical times, the village dogs had been eking out an existence on the human fringe for millennia. Their genomes thus reflected a state of early domestication, before artificial selection and inbreeding directed by humans had taken over. “When you are looking at village dogs,” Adam Boyko says, “you have something more akin to natural selection, albeit in an environment that’s managed by humans.”

Unexpectedly, the study also helped to challenge the reigning view on the place where dogs first appeared. Fossil evidence had already pinned the transition from wolf to dog somewhere in Europe or Asia, and a 2002 study had shown that East Asian village dogs were more genetically diverse—an indication that wolves had first been domesticated in East Asia. But the Boykos’ 2009 work found that the African village dogs were just as diverse as the East Asian ones. Some also carried a genetic signature shared with Middle Eastern gray wolves, supporting research by Robert Wayne and Bridgett vonHoldt of UCLA that points to the Middle East as the likely cradle of dogs.

The Boykos continue to expand their sample collection, with another expedition planned for Africa. And they’ve also begun using the same techniques to solve a related mystery: the strange disappearance of native dogs in South America. We know from the historical record that Native Americans had dogs. But previous population surveys in the Americas turned up only dogs with European heritage. “How do you ship so many dogs across the world that they completely replace the native dogs?” Boyko wonders, suspecting that in fact there may still be village dogs with native DNA in the remotest areas of the continent. So in August the three Boykos packed their bags and headed into the jungles of Peru, searching for the lost American dog.

I have written about the discovery that African village dogs were just as genetically diverse as East Asian dogs– which in part falsifies the hypothesis that dogs originated in East Asia. People like that hypothesis for some odd reason.

I did not know that the Boykos had discovered that some these African village dogs showed an affinity with Middle Eastern wolves,  which I think is very supportive of the hypothesis that Middle Eastern wolves– or very close relatives of the– are the most important population that contributed to the domestic dog.

Now, it doesn’t mean that phenotypically distinct domestic dogs first appeared in the Middle East. It just means that this population contributed to the majority of dogs we have today. The small dog gene that is found in purebred dogs is also found in some Middle Eastern wolves–likely coming from Canis lupus arabs. The smallest members of that subspecies weigh only 25 pounds.

I’m very excited that the Boykos are now looking at Latin American dogs to see if any possess indigenous ancestry. We know that virtually all Native American dogs in the US and Canada have largely been swamped with Western dog blood. Testing village dogs in remote areas of Peru might yield some interesting results, but keep in mind that “double-nosed” village dogs were found in Bolivia a few years ago. They likely derive “double-nosed” pointers that the Spanish brought over. Native peoples liked to use European dogs for the hunt, and in the colonies that later became the United States, laws were passed to prevent European colonists from selling their dogs to the Indians.

Native Americans’ preference for Western dogs would have been an important factor in the extinction of Native American dog strains.

Another important factor is that these dogs may not have had much resistance to European dog diseases. Just as their human owners were no match for small pox, it is possible that common diseases in European dogs were quite devastating to Native dog populations.

And then there is also the simple fact that Native peoples were conquered– and in some cases, exterminated.  Massive social disruption leads to people not being able to care for their dogs– much less selectively breeding them. These dogs wound up wandering the countryside, where they either melded into the wolf or coyote population in North America or were shot on sight.

Any dogs that proved useful to the new order in the Americas were quickly absorbed into the growing Western-derived dog population.

To answer the Boykos’ question from an historical perspective, the Spanish were bringing over scores of dogs. Dogs were a major tool of conquest and colonization. The Navajo and Apache herders use their dogs as livestock guardians– a technique they got from the Spanish. The sheep they keep are derived from an old Spanish strain, and it is possible that their dogs trace to Spanish and maybe some  remnant Native American dogs.

It will be interesting to see if the Boykos’ work reveals any clues to the extinction of Native American dog strains in South America.  It will also be interesting to see if they find any dogs with clear indigenous ancestry. As far as I know, only the dominant hairless mutation that is found in xoloitzcuintli, Peruvian Inca orchids, and “Chinese crested dogs” has been traced to the Americas before the arrival of Columbus.

It will also be interesting to see if any of these dogs, if they prove to have ancestry from indigenous dogs, share signatures with North America wolves or coyotes or with wolves from East Asia. The VonHolt and Wayne study mentioned in this article found that certain East Asian breeds have an affinity with Chinese wolves. Because Native Americans came to the New World via Asia, it would make sense that some of these dogs would show some affinity with Chinese wolves– just as these East Asian breeds do.

Interesting questions.

I don’t know if they can be answered!

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A new study is challening the theory that domestic dog has East Asian origins.

A new study is challenging the theory that domestic dog has East Asian origins.

Remember that oft-cited study that claims domestic dogs originated in East Asia?

Well, it turns out that the domestic dog’s origins might not be so clear as we once thought.

Peter Savolainen led that study, which compared the genetic diversity of dog populations throughout the world. It turned out in that study that East Asian dogs were more genetically diverse than other populations, and greater genetic diversity is generally associated at the point of origin.

I admit that I always had one reservation about that study. It included our Western breeds, which we all know aren’t that genetically diverse at all. But then I assumed from my reading of the methodology that African and indigenous American dog populations were also not as genetically diverse as the Asian populations.

Well, my assumptions were wrong.

A new study is underway that is challenging Savolainen’s findings.

Dr. Adam Boyko of the Department of Biological Statistics and Computational Biology at Cornell University is leading a new study of dog genetic diversity to see if the origin might be somewhere else. This new study is going to exclude European and Western purebred dogs. This will be a study of the genetic diversity of street dogs.

The early findings showed that African dog populations in Egypt, Uganda, and Namibia were just as genetically diverse as the populations of East Asia.

Now, that blows a hole in the theory that dogs come from East Asian wolves. Why? Because there are no C. lupus wolves in Africa, although there may have been a population of these animals in Libya and Egypt, which may have been absorbed into the golden jackal population. The Ethiopian wolf (C. simensis) is not an ancestor of the domestic dog, although it’s much more closely related to wolves than any species of jackal.

Further, we know that dogs are descended from some sort of Eurasian wolf. We just don’t know which subspecies. So dogs had to have come from Eurasia to Africa. But if they are as genetically diverse in Africa as they are in East Asia, then we simply don’t know where their exact origin is.

The clarity that came from Savolainen’s findings is now muddled.  Boyko’s team will continue to analyze the genetic diversity of dog populations to see if they can find the origin of domestic dogs.

All we know now is that it happened somewhere in Eurasia 15,000 to 40,000 years ago, and that dogs are conspecific with C. lupus.

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As you might imagine, I’m excited by this finding, because I found this particular study very interesting. Using archeological and paleontological methodology in concert with the DNA analysis, this study found that wolves and dogs were from a very genetically diverse species– I call them ancient wolves to differentiate between modern wolves and domestic dogs–  and that the first anatomically modern dogs were more than 30,000 years old. And what’s more their point of origin was in Europe.

Now, that finding did not square well with the Savolainen study’s findings, but I had not seen any other studies that could point to other origins of the domestic dog. I accepted Savolainen’s study as definitive.

This new Boyko study might be what is necessary to finally figure out where these animals were originally domesticated. And maybe those findings will fit better with what was found from the study remains of dogs and wolves from those European caves.

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Some of the preliminary findings in the Boyko study are that Rhodesian ridgebacks and Pharaoh hounds are not Africa. The Pharaoh hound finding isn’t new. The historical record and subsequent genetic studies showed a more recent origin for this breed in Malta, where it has been used to hunt rabbits. Now, we know it’s definitely not an African breed.  And I could have told you the Rhodesian ridgeback is not an indigenous African breed. First of all it is mostly comprised European mastiff breeds and sight and scent hounds. The ridge come from pariah dogs that were thought to be indigenous African dogs. However, they were most likely dogs of the Thai ridgeback type that were imported to South Africa by the Portuguese.

Another interesting finding in that Salukis and Afghan hounds share their DNA with Egyptian village dogs. That doesn’t surprise me. Basenjis, which we know are of definite recent African origin, are very closely related to Namibian and Ugandan village dogs.

After all, it was just a few decades ago that the basenji club went to the Congo in search of new blood. In 1990, the AKC even opened up the registry to allow this new African blood into the stud book. It is from this expedition that the brindle basenjis were introduced the bloodline.

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I can’t wait to see the results of the study.

All we know now is that domestic dogs are derived from some Eurasian wolf population. The finding that all dogs descend from a East Asian wolf ancestor appears to be, if not falsified, at least muddled considerably. And that’s a fascinating preliminary finding.

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