Mind that little Pekingese at your feet. It has a bit of wolf in it.Researchers in the US have proposed a new kind of genetic map designed to help trace current purebred dog breeds back to key earlier progenitor breeds.
It is generally agreed that all the domesticated breeds we know today began to emerge between 12,000 and 15,000 years ago from different wolf populations, said Ms Deborah Lynch of the Canine Studies Institute in Aurora, Ohio.
Yet the archaeological records show that by 8,000 years ago a wide range of distinct and physically very different dog breeds had already arisen.
Ms Lynch and a colleague, Dr Jenny Madcoy of the Fred Hutchinson Cancer Research Centre in Seattle, have developed an entirely new way to group and categorise modern breeds.
The work combines genetic studies, physical and behavioural characteristics, American Kennel Club (AKC) records and ancient historical records to produce 10 distinct breed groupings, an elaboration on the traditional six as espoused by the AKC.
Details of the breed map were presented yesterday at a session of the American Association meeting in Seattle.
Understanding the genetic family tree of man's best friend could prove beneficial for humans, too, Ms Lynch said.
"The reason to do the dog is No 1 because it is our favourite pet," she said.
"But the dog in many ways is the ideal species for the study of human disease." Dogs represent the most diverse form of mammal, with 300 distinct breeds.
Humans have small families and live for many years, but dogs breed in large numbers and have much shorter lives, making it easier to track genetic disease occurrence.
While 4,000 genetic disorders have been identified in humans, 400 have emerged so far in dogs.
"Of these 400 almost all of them are found in humans," and 85 per cent of the two genomes are estimated to be identical, Ms Lynch said.
Earlier work suggested that progenitor breeds emerged from wolf populations.
"The history of dogs is really the history of humans," Ms Lynch said. "They literally walked out of the caves with us."
