Small Dogs Emerged 12,000 Years Ago

A genetic study has found that small domestic dogs probably originated in the Middle East over 12,000 years ago, according to a study by the University of California

The researchers tracked the evolutionary history of the IGF1 gene and found that the version of the major gene determinant of small size probably originated as a result of the domestication of the gray wolf in the Middle East.

The scientists, led by Melissa Gray and Robert Wayne, examined a large sample of gray wolf populations. Gray explains, mutation of the small body size is after the domestication of dogs. However, as all small dogs possess this variant of IGF1, it probably arose early in its history.

"Our results show that the version of IGF1 gene discovered in small dogs is closely related to lions discovered in the Middle East and is consistent with an ancient origin in this region of small domestic dogs," says the researcher.

Previous archaeological work in the Middle East have unearthed the remains of small domestic dogs dating back 12,000 years. The sites in Belgium, Germany and western Russia contains the oldest remains of between 13,000 and 31,000 years, but these are of larger dogs. The findings support the hypothesis presented by the team of Gray that the small body size evolved in the Middle East.

The reduction in body size is a common feature of domestication and has been included in other domesticated animals like cows, pigs and goats. Gray concludes, "the small size could have been more desirable in densely populated agricultural societies, in which dogs may have lived partly outside or confined indoors."