Small domesticated dogs probably originated in the Middle East more than 12,000 years ago as the descendants of grey wolves, according to a gene study.
University of California at Los Angeles researchers Melissa Gray and Robert Wayne led a team that searched for variations of a gene called IGF1 which is a characteristic of small dogs.
"(The variant) probably arose early in their history," said Gray, whose paper is published online by BMC Biology, an open-access journal.
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"Our results show that the version of the IGF1 gene found in small dogs is closely related to that found in Middle Eastern wolves and is consistent with an ancient origin."
The work concurs with archaeological work in the Middle East that has unearthed the remains of small domestic dogs dating to 12,000 years ago. Digs in Europe have uncovered older remains, to as much as 31,000 years ago, but these are of larger dogs.
Canine selection may have been carried out by villagers in the Fertile Crescent of modern-day Iraq and other cradles of agriculture.
"Small size could have been more desirable in more densely-packed agrarian societies where dogs may have lived partly indoors or in confined outdoor spaces," says the study.
