Interesting article about origin of dogs

ScienceDaily (Aug. 6, 2009) — African village dogs are not a mixture of modern breeds but have directly descended from an ancestral pool of indigenous dogs, according to a Cornell-led genetic analysis of hundreds of semi-feral African village dogs.

That means that village dogs from most African regions are genetically distinct from non-native breeds and mixed-breed dogs. They also are more genetically diverse because they have not been subjected to strict breeding, which artificially selects genes and narrows breeds' gene pools.

The study, published online Aug. 3 in the Proceedings of the National Academy of Sciences, sheds light on the poorly understood history of dog domestication. Future work may help explain the timing and locations of dog domestication and how dogs have adapted to the African environment, human settlements and dietary shifts.

"The genes of modern breeds all cluster together in one little group, but the African village dogs we sampled show much greater diversity genetically," said lead author Adam Boyko, a research associate in the lab of Carlos Bustamante, the paper's senior author and a professor of biological statistics and computational biology.

Field researchers from the University of California-Davis, who are part of the Cornell-based Village Dog Genetic Diversity Project, and others, including local veterinarians, sampled 318 village dogs from seven regions in Egypt, Uganda and Namibia.

They also looked at breed dogs, including those reputed to be from Africa, Puerto Rican dogs and mixed-breed dogs from the United States. Researchers and veterinarians also collected photos and information on weight, age, coat color and body measurements and sent blood samples for analysis to the Canine DNA Bank at the Baker Institute for Animal Health, part of Cornell's College of Veterinary Medicine, which maintains a growing DNA archive of dogs worldwide.

Boyko, Bustamante and colleagues used a computer program to track genetic diversity in the samples. They found that the African village dogs are a mosaic of indigenous dogs descended from early migrants to Africa and non-native mixed-breed dogs. Such reputed African breeds as Pharaoh hounds and Rhodesian ridgebacks clustered with non-native dogs, suggesting they originated from outside of Africa.

A previous study of village dog genetics confirmed that domesticated dogs likely originated from Eurasian wolves some 15,000 to 40,000 years ago, and reported that East Asian village dogs had more genetic diversity than any others sampled for the study, suggesting that dogs were first domesticated in East Asia. But the African village dogs analyzed in this study revealed similar genetic diversity, which raises doubt on the claim that dogs were first domesticated in East Asia.

As the group continues to collect samples from worldwide locations, including the Americas, the researchers will explore where modern breeds originated and how much genetic diversity has been lost with the development of modern breeds.

The researchers are interested in working with dog owners and local veterinarians to get more DNA samples of dogs from remote corners of the world.

Co-authors included Heidi Parker and Elaine Ostrander, geneticists at the National Human Genome Research Institute; Rory Todhunter, a professor of clinical sciences in Cornell's College of Veterinary Medicine; and Paul Jones, a genetics researcher at the Waltham Centre for Pet Nutrition in the United Kingdom, among others.

The study was funded by Cornell's Center for Vertebrate Genomics, Department of Clinical Sciences and Baker Institute of Animal Health; the National Institutes of Health; and the National Science Foundation.

I do think it's funny they were surprised pharaoh hounds tested out as being a non african breed, since they are a recent recreation and not the same lineage as dogs in the egyptian tombs.

I always end up yelling at the TV during Westminster and Eukanuba because the announcers continue to claim that Ibizans and Pharaoh hounds are the dogs on the pyramids even though we've known for a handful of years now that they are modern breeds. Drives me crazy!

I doubt Ostrander was actually surprised about the results concerning the pharaoh hound because she was head of the team that showed the breed was modern, not ancient. Cool article. Thanks for posting it.

How about Chihuahuas? Are they actually indigenous to South America, which might indicate yet a third point of domestication?

I think somebody once did a study of Indian pariah dogs. Seems that after X generations* of catch-as-catch-can breeding, all the dogs looked pretty much the same: in the 30 lb. range, pointed muzzle, curled tail, short brown fur.

*And not that many generations, either, as far as I can remember. Seems to be an ur-dog template!

That's one of the main reasons I do not believe dogs are descended from wolves. If they were, they should all start reverting to wolfy beasts after a few generations. Instead they revert like you describe. There is probably some extinct wild canid that looked like our feral dogs.

This has been my contention for some time, but anytime I suggest that dogs may well not be directly descended from wolves at all, but from a smaller dog-like animal, everyone thinks I'm crazy. I always thought this too, was interesting food for thought.... albeit an unpopular theory among the dogs are wolves crowd. lol.

Darren Naish: Tetrapod Zoology: Controversial origins of the domestic dog

Mexico may claim the Chihuahua, and Tibet the shih tzu. But a new genetic study indicates that all small dogs have their origins in the Middle East.

The origin of the domestic dog is a hot topic in evolutionary biology. Scientists agree that today's Fidos came from the domestication of the gray wolf, but they are at odds over where this took place. Previous genetic studies focusing on mitochondrial DNA—inherited only from the mother—have suggested that modern domestic dogs are descended from animals that lived in East Asia between 5000 and 16,000 years ago. But archaeological excavations in Europe and the Middle East have found remains of what appear to be domestic dogs dating back as far as 31,000 years.

Now, a team led by evolutionary geneticist Melissa Gray of the University of California, Los Angeles, has examined nuclear DNA to fill in a crucial piece of the puzzle. The researchers took samples of blood, tissue, or saliva from three populations: large domestic dogs (those weighing more than 30 kilograms), small dogs (weighing less than 9 kilograms), and wild wolves, foxes, and coyotes from around the world. They then looked at a gene called insulin-like growth factor 1 (IGF1). All canines, wild or domestic, have some form of this gene—precisely which form is strongly associated with the size of an animal's skeleton.

The team found that the version of IGF1 carried by all small dogs is found in very few large dogs and no wild canines. But a very similar form of the gene is found in gray wolves from the Middle East. That means that this region is probably the birthplace of the common ancestor of all the world's small dogs. Because they all carry the same variant, it is extremely unlikely that small body size evolved more than once. And for the gene to have had time to spread all over the world, it must have evolved shortly after dogs were first domesticated.

Gray emphasizes that the study, published today in BMC Biology, doesn’t necessarily mean that dogs were first domesticated in the Middle East. But it's a "strong indication" that that region “has played a significant role in the early history of domestic dogs.” The authors note that archaeologists have found remains of small dogs dating to 12,000 years ago in the area. There are older sites in Europe and Russia, but they contain larger dogs. She says humans living in small agricultural communities may have deliberately bred small dogs because they ate less and could be kept in small spaces.

Adam Boyko, a geneticist at Stanford University in Palo Alto, California, who specializes in the evolution of the domestic dog, is impressed by the study. “This really pokes a hole in the argument of this relatively simple domestication in East Asia, ... which is what people have been arguing based on mitochondrial DNA,” he says.

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