Who’s your doggy?

Through the marvels of DNA testing, dogs of vague or unrecognizable ancestry – whether fluffy white mongrels with Chihuahua ears and beagle-like voices or massive hounds that resemble nothing previously seen in nature – are being exposed for what they really are, genetically speaking.

DNA testing can disclose what breeds dominate their family trees. And thousands of people are happy to pay, from about $60 to $170 depending on the method and company chosen, to end the what-do-you-suppose-he-is speculation of mixed-breed dog owners everywhere.

The first test was unveiled less than a year ago, and consumer interest is growing so fast that more companies are jumping into the dog-identification business, Web sites are being enhanced, and additional breeds are regularly being added to testing databases.

“Pure curiosity, getting the answer” is the reason most owners seek out the testing, says Neale Fretwell, head geneticist for Mars Veterinary, maker of the Wisdom Panel MX Mixed Breed Analysis that can determine which of 134 breeds recognized by the American Kennel Club composes a dog’s genetic makeup.

And some of the answers are real stunners - not just for the owners, but for the veterinarians who have made their best guesses, Fretwell says.

The procedure requires an appointment with a veterinarian to draw a blood sample and when analysis is completed in two or three weeks, a follow-up visit to discuss the findings. The pricing is set by individual vets and costs $135 to $170.

Another reason owners go the testing route is to uncover possible explanations for behaviors that might be inherited, such as herding people and other pets or rooting around in chipmunk or mole holes.

Other owners want to know whether their dog has a high proportion of a breed predisposed to a particular ailment or frailty, although experts caution it’s impossible to know which traits, including propensity for disease or medical issues, a mongrel might inherit from any particular breed.

No one offering these tests suggests a mongrel assumes some sort of elevated status upon learning a purebred bloodhound or dachshund entered his ancestry generations ago.

Indeed, the companies celebrate the characteristics of mixed breeds, and some experts applaud “hybrid vigor,” the belief that mixing unrelated breeds can create a stronger, healthier dog than purebreds, which can pass on genetic conditions found in specific breeds.

Many clients are “very surprised” upon receiving word of what breeds populate their dog’s background, Fretwell says.

Meg Retinger, chief administrative officer of BioPet Vet Lab in Knoxville, Tenn., says, “Some people say, ‘That’s just exactly what I thought.’ ” Others “have such preconceived notions about what their pet is they just won’t accept the results.”

In January, the lab began marketing its $59.95 DNA Breed Identification kit that tests for 61 AKC breeds using cheek cells scraped by the owner.

But the signature appearance characteristics of a particular breed don’t always materialize, even when there’s a high proportion of that breed in a dog, Fretwell says.

A mongrel with a German shepherd parent or grandparent, for example, might not have the black and tan coloring, the saddle pattern on its back or even the long muzzle. Some could not show any shepherd characteristics.

Size, color and a host of physical features such as ear and muzzle shape and tail type are influenced by genetics, and when several breeds meld in one dog, it’s tough for even experts to eyeball a mutt and accurately assess what lies within.

Connie Steele of Colorado Springs, Colo., learned this. Earlier this year she adopted a black-and-white dog that shelter personnel thought was mostly border collie and about 1 1/2 years old. She soon discovered from her vet that Ellie was still a puppy, probably less border collie than believed and almost certain to grow a lot more.

Steele got Ellie tested because, she jokes, she wanted “a bit of warning if I’m going to need to plan ahead for a larger house to accommodate a 2-year-old pony-sized dog.”

Upon receiving Ellie’s results, Steele did not begin house-shopping, though she was surprised by the breeds found in her background. Steele believes the information she now has about Ellie and also Kayla, another recently adopted shelter dog, offers clues about how to approach their training.

Most DNA tests show three or four different breeds in the mixed breeds’ ancestries, and many show five or six, experts say. Several more likely are in the mix, but the amounts have been so dissipated over the generations, they are merely weak traces, unlikely to influence a dog’s appearance or behavior.

And, yes, a few dogs are comprised of so many disparate breeds, the experts and their tests just can’t solve the puzzle.

“Even the best test can’t answer every question of biology,” says Dennis Fantin, chief of operations for MetaMorphix, a Beltsville, Md., firm that has done testing for the AKC for years. The company now offers a $119.95 mixed-breed cheek-swab kit. The Canine Heritage XL Breed Test can detect 108 breeds.

Sometimes, any pure DNA has become “so diluted” by encounters with mixed breeds over the generations, no answers emerge, Fantin says.

Their owners are told the mystery must remain. Money refunded.