Dog-Gone Genetics: A Few Genes Control Fido's Looks | WAMU 88.5 - American University Radio

Dog-Gone Genetics: A Few Genes Control Fido's Looks

Play associated audio

Humans are complicated genetic jigsaw puzzles. Hundreds of genes are involved in determining something as basic as height.

But man's best friend is a different story. New research shows that almost every physical trait in dogs — from a dachshund's stumpy legs to a shar-pei's wrinkles — is controlled by just a few genes.

Writer Evan Ratliff has been looking into dog genetics for National Geographic Magazine. He tells weekends on All Things Considered host Guy Raz that that quirk makes it extremely easy for breeders to develop new, custom-designed dogs — like the German hunters who bred the original dachshunds a few hundred years ago.

"These German hunters wanted some sort of dog to hunt badgers and other sort of small rodents that live in holes." So they crossed long, low basset hounds with tenacious terriers, to produce a dog that could chase badgers into their dens and then be yanked out again by the tail if necessary. The breeders also built in loose fur, so any bites wouldn't do much damage.

Other breeds, like the shar-pei, developed after breeders pursued a particularly favored look, Ratliff says.

For years, scientists thought that dogs were just as genetically complicated as humans, Ratliff says. But that turned out not to be the case. Scientists at Cornell, UCLA, Stanford and the National Institutes of Health have been comparing dog DNA as part of a project called CanMap.

"They took a whole large collection of dogs, 900 dogs from, I think, 80 breeds," Ratliff says. "And what they learned was that in these dogs, if you look at their physical traits, everything from their body size to their coat color to whether they have floppy ears, it's determined by a very small number of genes."

It's actually human interference that's the cause of what Ratliff calls "Tinker-Toy genetics" in dogs. "The way that natural selection works, it usually works on very small changes," he says. Sudden large changes can actually be harmful.

But breeders can introduce large changes in a dog relatively rapidly, by selecting the genes that have the strongest effects.

"If I want a tall dog, a large dog, then I end up selecting for this gene called IGF1, which has a very very strong effect on the size of a dog. And when you do that over a couple of hundred years, what happens is ... it becomes the gene that controls body size."

No word yet on which genes control loyalty, dog breath, or a propensity to slobber on your slippers.

Copyright 2012 National Public Radio. To see more, visit http://www.npr.org/.

NPR

Speed Dating For Seniors Who Aren't Interested In Slowing Down

A new film follows daters ages 70 to 90 looking for love in five-minute intervals. "Speed dating for seniors" may sound funny, but The Age of Love is really about our lifelong need for intimacy.
NPR

Eat Your Veggies! Even The Ones From Fukushima

Foods from Fukushima, Japan, are back to pre-accident levels of radiation but people still aren't eating them. One way to ease concerns: a chemical that blocks radioactive cesium from entering plants.
WAMU 88.5

Fairfax County Supervisors Approve Pay Bump For Themselves

Members of the Fairfax County Board of Supervisors are about to start earning more money, as the current members have approved a measure that will raise salaries for the next board.
NPR

Sharing Patient Records Is Still A Digital Dilemma For Doctors

There's good news and bad news about electronic medical records. They're now in most doctors' offices — but most doctors still can't easily share them.

Leave a Comment

Help keep the conversation civil. Please refer to our Terms of Use and Code of Conduct before posting your comments.