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TORONTO — It's hard to imagine when looking at Rex the lumbering St. Bernard and Fifi the frou-frou toy poodle, but it appears most breeds of domesticated dogs can trace their ancestry to the same source - the Middle Eastern grey wolf.
That's the conclusion of an international team of scientists that analyzed the genomes of more than 900 dogs belonging to 85 breeds and about 200 grey wolves from different regions around the world, including Canada.
"Dogs seem to share more genetic similarity with Middle Eastern grey wolves than with any other wolf population worldwide," said senior investigator Robert Wayne, a professor of ecology and evolutionary biology at the University of California, Los Angeles.
Previous genetic research had suggested that canines were descended from wolves first domesticated in East Asia.
But using a whole-genome approach - analyzing more than 48,000 genetic locations in DNA samples from the animals - the team found that most dogs share more unique markers with Middle Eastern wolves than with East Asian wolves.
"There is so much similarity between the current dogs and some wolves of the Middle East, we can just infer that this is where people have domesticated dogs from wolves first," said co-author Marco Musiani, a landscape ecologist at the University of Calgary.
The finding also is much more consistent with the archeological record, said Wayne. "We know that dogs from the Middle East were closely associated with humans because they were found in human burial sites; in one case, a puppy is curled up in the arms of a buried human."
"This is the same area where domestic cats and many of our livestock originated and where agriculture first developed," he said, referring to the Fertile Crescent that includes modern-day Iraq, Syria and Israel.
However, the first tentative steps that began the transformation of wolves into humankind's best friend probably date from 15,000 to 30,000 years ago, even as much as 50,000 years ago. "And that means that dogs were domesticated with hunter-gatherers, rather than the first agriculturalists," Wayne said from Los Angeles.
"Hunter-gatherers, many were nomadic moving across the landscape. Wolves probably took up with them and took advantage of carcasses and other resources that humans provided. And that initial kind of association developed into a closer association with time, where these protodogs may have provided protection or assisted in the hunt.
"Dogs are the only large carnivore ever domesticated."
The researchers, whose work is published in this week's online edition of the journal Nature, have also constructed a comprehensive genetic tree of dog breeds and wolf species.
Eighty per cent of dog breeds are modern, evolving over the last few hundred years; some are ancient, going back thousands of years. While most dogs are genetically related to the Middle Eastern wolf, a small number of East Asian breeds, including the Akita and chow chow, show a higher level of genetic sharing with Chinese wolves, the researchers found.
What surprised them was how much diversity there is among modern-day dog breeds, despite their common ancestral link, which runs along lines related to function. Within the canine family, there are groupings of breeds that coincide with a distinct behaviour, such as herding or retrieving.
"All dogs are about equally distanced from wolves," said Wayne. "So they all have a single common ancestor and then have diverged after that point ... Most of the modern breeds are products of Victorian-era selective breeding processes, which were very different from what occurred in antiquity."
Musiani, who specializes in wolf genetics and behaviour, said wolves the world over have a similar appearance. The wild canines have retained virtually the whole gene pool and most of the behaviours of their ancient ancestors, while humans have bred dogs to hive off certain physical and functional characteristics.
"Some dogs are very little, some dogs are hunting dogs, some dogs are guard dogs, and so on and so forth," Musiani said from Calgary.
"Wolves, they have a bit of everything ... they have pretty much all the behaviours that each dog breed has. Wolves, they can chase. Wolves, they can stalk. Wolves, they can bark - few people know that. Also they howl and growl."
"In dogs, we have in just a few thousand years selected dogs that mainly bark - and those would be the guard dogs. It's an advantage if a dog barks because it's an alarm signal. We have selected dogs that mainly chase, like the greyhound ... We have selected dogs that stalk, like the pointer."
"This paper highlights the power of artificial selection and technology to modify nature to satisfy our own needs."
http://www.google.com/hostednews/canadianpress/article/ALeqM5gXMjgBN_z0ZHBp12Cvmm8mqnoL6g
That's the conclusion of an international team of scientists that analyzed the genomes of more than 900 dogs belonging to 85 breeds and about 200 grey wolves from different regions around the world, including Canada.
"Dogs seem to share more genetic similarity with Middle Eastern grey wolves than with any other wolf population worldwide," said senior investigator Robert Wayne, a professor of ecology and evolutionary biology at the University of California, Los Angeles.
Previous genetic research had suggested that canines were descended from wolves first domesticated in East Asia.
But using a whole-genome approach - analyzing more than 48,000 genetic locations in DNA samples from the animals - the team found that most dogs share more unique markers with Middle Eastern wolves than with East Asian wolves.
"There is so much similarity between the current dogs and some wolves of the Middle East, we can just infer that this is where people have domesticated dogs from wolves first," said co-author Marco Musiani, a landscape ecologist at the University of Calgary.
The finding also is much more consistent with the archeological record, said Wayne. "We know that dogs from the Middle East were closely associated with humans because they were found in human burial sites; in one case, a puppy is curled up in the arms of a buried human."
"This is the same area where domestic cats and many of our livestock originated and where agriculture first developed," he said, referring to the Fertile Crescent that includes modern-day Iraq, Syria and Israel.
However, the first tentative steps that began the transformation of wolves into humankind's best friend probably date from 15,000 to 30,000 years ago, even as much as 50,000 years ago. "And that means that dogs were domesticated with hunter-gatherers, rather than the first agriculturalists," Wayne said from Los Angeles.
"Hunter-gatherers, many were nomadic moving across the landscape. Wolves probably took up with them and took advantage of carcasses and other resources that humans provided. And that initial kind of association developed into a closer association with time, where these protodogs may have provided protection or assisted in the hunt.
"Dogs are the only large carnivore ever domesticated."
The researchers, whose work is published in this week's online edition of the journal Nature, have also constructed a comprehensive genetic tree of dog breeds and wolf species.
Eighty per cent of dog breeds are modern, evolving over the last few hundred years; some are ancient, going back thousands of years. While most dogs are genetically related to the Middle Eastern wolf, a small number of East Asian breeds, including the Akita and chow chow, show a higher level of genetic sharing with Chinese wolves, the researchers found.
What surprised them was how much diversity there is among modern-day dog breeds, despite their common ancestral link, which runs along lines related to function. Within the canine family, there are groupings of breeds that coincide with a distinct behaviour, such as herding or retrieving.
"All dogs are about equally distanced from wolves," said Wayne. "So they all have a single common ancestor and then have diverged after that point ... Most of the modern breeds are products of Victorian-era selective breeding processes, which were very different from what occurred in antiquity."
Musiani, who specializes in wolf genetics and behaviour, said wolves the world over have a similar appearance. The wild canines have retained virtually the whole gene pool and most of the behaviours of their ancient ancestors, while humans have bred dogs to hive off certain physical and functional characteristics.
"Some dogs are very little, some dogs are hunting dogs, some dogs are guard dogs, and so on and so forth," Musiani said from Calgary.
"Wolves, they have a bit of everything ... they have pretty much all the behaviours that each dog breed has. Wolves, they can chase. Wolves, they can stalk. Wolves, they can bark - few people know that. Also they howl and growl."
"In dogs, we have in just a few thousand years selected dogs that mainly bark - and those would be the guard dogs. It's an advantage if a dog barks because it's an alarm signal. We have selected dogs that mainly chase, like the greyhound ... We have selected dogs that stalk, like the pointer."
"This paper highlights the power of artificial selection and technology to modify nature to satisfy our own needs."
http://www.google.com/hostednews/canadianpress/article/ALeqM5gXMjgBN_z0ZHBp12Cvmm8mqnoL6g