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

When Wildlife Documentaries Jump The Shark

Networks like the Discovery Channel have been criticized for pushing entertainment at the cost of science, with fake "documentaries" about everything from mermaids to mythical monster sharks.
NPR

Can Oxfam Nudge Big Food Companies To Do Right?

Oxfam is scoring the 10 biggest food companies on a scale of 1 to 10 on a host of issues, from worker rights to climate change. But will promises translate into concrete changes?
NPR

Rick Perry's Legal Trouble: The Line Between Influence And Coercion

The Texas governor is charged with abuse of office and coercing a public official, but he claims he was just doing what governors do: Vetoing a budget item.
NPR

New GoPro Camera Harness Captures Dog's-Eye View

This past week, the camera maker GoPro unveiled the Fetch harness, which allows people to attach the durable cameras to their dogs. The company was inspired by some DIY efforts at pet videography.

Leave a Comment

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