Thanks to the Sun Sentinel for this informative article.
Dogs as guinea pigs in quest for genetic perfection
By Amy Harmon
New York Times News Service
FT. MOTT STATE PARK, N.J. — When mutant, muscle-bound puppies started showing up in litters of champion racing whippets, the breeders of the normally sleek dogs invited scientists to take DNA samples at race meets across the country. They hoped to find a genetic cause for the condition and a way to purge it from the breed.
It worked. “Bully whippets,” as the heavyset dogs are known, have a genetic mutation that enhances muscle development. And breeders may not want to eliminate the “bully” gene — the scientists found that the same mutation that pumps up some whippets makes others among the fastest dogs on the track.
With a DNA screening test on the way, “We’re going to keep the speed and lose the bullies,” said Helena James, a whippet breeder in Vancouver, British Columbia.
Free of most of the ethical concerns associated with the practice of eugenics in humans, dog breeders are seizing on new genetic research to exert dominion over the canine gene pool. Companies like Vetgen and Healthgene offer dozens of DNA tests to tailor the way dogs look, improve their health and, perhaps soon, enhance their athletic performance.
But as dog breeders apply scientific precision to their age-old art, they find that the quest for genetic perfection comes with unforeseen consequences. And with DNA tests on the way for humans, the lessons of intervening in the nature of dogs may ultimately bear as much on us as on our best friends.
“We’re on the verge of a real radical shift in the way we apply genetics in our society,” said Mark Neff, associate director of the veterinary genetics laboratory at the University of California, Davis. “It’s better to be first confronted with some of these issues when they concern our pets than when they concern us.”
Some Labrador breeders are using DNA tests to guarantee exotic silver-coated retrievers. Mastiff breeders test for shaggy fur to avoid “fluffies,” the long-haired whelps occasionally born to short-haired parents. Scientists who recently completed the first map of a dog genome (of a boxer named Tasha) are now soliciting samples from dog owners across the world to uncover the genetic basis for a slew of other traits.
Even before the entire genome was decoded, breeders were already making use of DNA screening tests to make more informed decisions about which to mate.
But because genes are often tied to multiple traits, scientists warn, deliberate selection of certain ones can backfire. The gene responsible for those silver-coated Labradors, for example, is tied to skin problems.
With the genetic curtain lifted, breeders also take on a heavier burden for the consequences of their choices. Whippet breeders who continue to mate fast dogs with one another, for instance, now do so knowing they may have to destroy the unwelcome bullies such pairings often produce.
Moreover, the prospect of races being won by dogs intentionally bred to have a genetic advantage may bring new attention to the way that genes contribute to canine — and human — achievement.