Canine family tree reflects human hand

WASHINGTON - Most genetic variation in modern dogs was introduced by humans through selective breeding programs, researchers have found.

This is among the surprising findings of a comparison of dog and wolf DNA by researchers building a canine family tree.

Researchers took DNA samples from 414 purebred dogs representing 85 breeds to see how the canine genome accounts for the smallest Pekinese, curly poodle or herding border collie.

Scientists used a computer program and statistical analysis to identify a dog's breed based on the subtle differences in its genetic profile.

Geneticist Elaine Ostrander of the Fred Hutchinson Cancer Research Centre in Seattle and her colleagues found the breeds evolved into four main groups:

* An ancient group of older hounds like the Afghan, dogs of Asian origin, such as the Chinese Shar-pei, and the northern Spitz dogs like the Siberian Huskey most closely resembled the wolf.
* The Mastifs such as Rottweilers, bulldogs and boxers that share large bodies and square-shaped heads.
* Working dogs like collies and sheep dogs.
* Sporting dogs like hounds and terriers.