The mystery is over -- one of them, anyway.

I got the answer to the question everyone asks in a voice mail, informing me that my dog's DNA showed two primary breeds.

The face (and tail) that launched a thousand guesses is -- largely -- Rottweiler and chow.

Since adopting my dog Ace a year and a half ago, I'd heard dozens of possible combinations -- from the shelter where I got him, from veterinarians, from other dog owners -- but not that exact one.

Now, my two-month-long quest to find the roots of my mutt was over -- with, appropriately enough, mixed results.

As far as his past, we'd learned from our return to the Baltimore Animal Rescue and Care Shelter, known as BARCS, that Ace was a stray, found on the street by a citizen in the 21229 ZIP code who called animal control. Ace weighed in at 50.9 pounds, spent 17 days in the shelter and drew 302 clicks on petfinder.com during that period.

Our trip to 21229 was unfruitful, though Ace made some new friends. Everybody liked Ace; but nobody knew him.

And our visit from an animal communicator -- though she said Ace revealed to her that he was abandoned by his family when he grew too big and proved too gentle to be the fighting dog it wanted -- was not the kind of hard-and-fast, twice-confirmed, indisputable-as-DNA evidence we journalists most like to be fed.

The DNA test I administered and popped in the mail had led to probably my strongest finding -- that Ace was Rottweiler and, more surprising, chow, a dog that, while curly-tailed, is short in stature.

Do the test results mean that Ace is a product of a purebred Rottweiler and a purebred chow? Not necessarily. It just means that, of the 38 breeds MMI Genomics' $65 Canine Heritage test checks for, Rottweiler and chow are the only two that showed up.

More likely, if purebreds were involved at all, they lay further back in his lineage, along with many other breeds not on the list of 38.

So, can I call him a "chow-weiler?"

"If you wanted to be exact you could say the genetic structure of his DNA reflects that of a purebred Rottweiler and a purebred chow," said Sue DeNise, vice president of genomic research at MMI Genomics.

"Or you could say he's a mix of breeds, and that those include a high extent of Rottweiler and chow," said Dennis Fantin, its chief of operations.

The people at MMI Genomics point out that, while the biggest appeal of the new test may be the fun of it -- the joy that dog owners get in satisfying their curiosity -- it can also be useful in understanding your dog's health and behavior.

Chows, for example, can be willful, introverted and obstinate -- in addition, of course, to their many good traits. While highly loyal, they can be detached -- a remnant, some dog books say, of the way they were once treated long ago in China, when they were used for fur and meat.

Rottweilers, some dog manuals contend, require firm and careful training to ensure they don't become overly aggressive, especially around other dogs. While those I've met have all had sweet dispositions, the muscular build and large body of the Rottweiler, as well as their use as guard dogs, have given the breed a reputation, among some, as dogs to be feared.

With dogs, as with people, the reputations are sometimes out of proportion with the reality.

It is for just those reasons that MetaMorphix avoided including pit bulls in the 38 breeds they test for. With some cities considering legislation against the breed, the company worried that its test could be used to terminate animals.