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Dog DNA
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March 19, 2010, 03:31 AM
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Nicholas Wade reports in the NYT on the latest on dog DNA:
Borrowing methods developed to study the genetics of human disease, researchers have concluded that dogs were probably first domesticated from wolves somewhere in the Middle East, in contrast to an earlier survey suggesting dogs originated in East Asia.

This finding puts the first known domestication — that of dogs — in the same place as the domestication of plants and other animals, and strengthens the link between the first animal to enter human society and the subsequent invention of agriculture about 10,000 years ago.

A Middle Eastern origin for the dog also fits in better with the archaeological evidence, and has enabled geneticists to reconstruct the entire history of the dog, from the first association between wolves and hunter gatherers some 20,000 years ago to the creation by Victorian dog fanciers of many of today’s breeds.

A research team led by Bridgett M. vonHoldt and Robert K. Wayne of the University of California, Los Angeles, has analyzed a large collection of wolf and dog genomes from around the world. Scanning for similar runs of DNA, the researchers found that the Middle East was where wolf and dog genomes were most similar, although there was another area of overlap between East Asian wolves and dogs. Wolves were probably first domesticated in the Middle East, but after dogs had spread to East Asia there was a crossbreeding that injected more wolf genes into the dog genome, the researchers conclude in Thursday’s issue of the journal Nature.

The archaeological evidence supports this idea, since some of the earliest dog remains have been found in the Middle East, dating from 12,000 years ago. The only earlier doglike remains occur in Belgium, at a site 31,000 years old, and in western Russia from 15,000 years ago. ...

Several thousand years later, in the first settled communities that began to appear in the Middle East 15,000 years ago, people began intervening in the breeding patterns of their camp followers, turning them into the first proto-dogs. One of the features they selected was small size, continuing the downsizing of the wolf body plan. �I think a long history such as that would explain how a large carnivore, which can eat you, eventually became stably incorporated in human society,� Dr. Wayne said. ...

Dr. Wayne was surprised to find that all the herding dogs grouped together, as did all the sight hounds and the scent hounds, making a perfect match between dogs’ various functions and the branches on the genetic tree. �I thought there would be many ways to build a herding dog and that they’d come from all over the tree, but there are not,� Dr. Wayne said.

This suggests that the first step, wolf to dog was the hardest, then generic dog to herding dog was also hard, while making subsequent variations on herding dog is easy. I don`t know why dog breeders have given up on creating new functional breeds. For example, it is becoming common in New York City among people looking to rent an apartment to hire a dog to come sniff for bed bugs? Why not create a bed bug sniffing breed that is outstanding at this?
His team has also used the dog SNP chip to scan for genes that show signatures of selection. One such favored dog gene has a human counterpart that has been implicated in Williams syndrome, where it causes exceptional gregariousness.
That`s pretty funny.
Dog domestication and human settlement occurred at the same time, some 15,000 years ago, raising the possibility that dogs may have had a complex impact on the structure of human society. Dogs could have been the sentries that let hunter gatherers settle without fear of surprise attack. They may also have been the first major item of inherited wealth, preceding cattle, and so could have laid the foundations for the gradations of wealth and social hierarchy that differentiated settled groups from the egalitarianism of their hunter-gatherer predecessors. Notions of inheritance and ownership, Dr. Driscoll said, may have been prompted by the first dogs to permeate human society, laying an unexpected track from wolf to wealth.
Domesticating dogs was a big deal, although we don`t know in what precise ways.