Genetic link eyed in dogs' troubled ways

September 03, 2007|Judy Foreman

All summer, Dr. Nicholas Dodman, head of the animal behavior clinic at the Cummings School of Veterinary Medicine at Tufts University, has been in doggie heaven.

Using brand new genetic "chip" technology developed by researchers at the Broad Institute of Harvard and MIT, where the entire dog genome was sequenced a couple of years ago, Dodman is finally poised to do the experiments he's been waiting years to do, exploring the genetics of complex psychiatric problems in dogs.

First, he'll compare the DNA he has collected from Doberman pinschers who suck fanatically on their own flanks with DNA from normal Dobermans to see precisely where the genes for this compulsive disorder lie. Then, he will do the same DNA comparisons of normal bull terriers and abnormal ones with another compulsive behavior, endless tail chasing. Dodman and other scientists also hope to use the latest techniques to find the genetic roots of rage in Springer spaniels, which in theory might help explain some human aggression.

"This is absolutely revolutionary," Dodman said last week.

Until the new MIT chip technology came along, the Tufts team was looking gene by gene to try to unravel the genetic origin of compulsive behavior in dogs. Now, they can search for multiple genes at once, knowledge that should also shed light on aggression and obsessive-compulsive disorders, or OCD, in people.

"It's like the difference between searching house by house for insurgents in Iraq and looking at the whole of Baghdad at once," he said.

These diseases can be easier to study in dogs than humans.

"The genetics of obsessive-compulsive disorder and other mental illnesses are likely to be very complex - and very difficult to study in humans," said Dr. Francis Collins, director of the National Human Genome Research Institute at the National Institutes of Health. "With their selective breeding and well-characterized behaviors, purebred dogs may provide a powerful system for untangling the genetic roots of these disorders." purebred dogs may provide a powerful system for untangling the genetic roots of these disorders."

Incessant tail chasing, for instance, is very breed-specific in dogs, said Alice Moon-Fanelli, a Tufts behavioral geneticist who works with Dodman. When people bring their pets in for excessive tail chasing, "nine times out of 10, it's a bull terrier or a German shepherd."