Pancho is a long, small dog with big ears who was adopted from the Berkeley Humane Society in 2003. Everyone who meets him has her own guess at Poncho's mysterious parentage: a terrier mix, a little pit bull, or perhaps a Chihuahua-pit bull mix, otherwise known as a Chia pit?

Sixty-five dollars and a simple swab of the inside of the cheek could finally solve that riddle. A new genetic test, marketed by Maryland-based MetaMorphix, can determine a dog's mix of breeds with 90 percent accuracy. The company has processed thousands of tests since the product went on the market in February, CEO Edwin Quattlebaum said at the Biotechnology Industry Convention in Boston earlier this week.

Because many canine diseases are linked to particular breeds, the results could help owners make health decisions about their dogs. The test has also garnered interest from animal shelters: shelter employees say that being able to provide a bit of a dog's "back story" encourages people to adopt. "Owners get a kick out of knowing the heritage of their dogs," says Quattlebaum.

The test assesses genetic markers known as single nucleotide polymorphisms, or SNPs. Each breed--the test can currently detect 38 of the most common--has a different SNP profile. The test is made possible by massive efforts to sequence the genome of different breeds of dogs, such as the dog genome project. (See "Dog DNA May Lead to Cures.")

MetaMorphix, which also does genetic testing for the American Kennel Club, is now starting to use its canine DNA database to hunt for genetic variations linked to diseases. Its first target is chronic hip dysplasia, a degenerative joint disease most often seen in large breeds, such as German shepherds, Labrador retrievers, rottweilers, Great Danes, and golden retrievers. "Eventually, people buying dogs could use this test to ensure their dog is not predisposed to this disease," says Quattlebaum. "And breeders could use it to try to breed [that variation] out of their dogs."

Victoria Jaschob, Pancho's devoted human companion, says that she's thought about ordering the test. But for now, "we just use the generic term 'Pancho dog' to describe any small, long dog with short legs and big ears," she says. "There's a million of them out there."