Let's say you're one of those kindhearted souls who went to an animal shelter one day and fell in love with one special dog. He just looked at you in that certain way that made you have to take him home. The shelter worker tells you she thinks he's mostly Beagle, but looks like there's a bit of Boxer, and maybe a little Labrador Retriever.

Later, as you proudly walk your new companion, or visit a dog park or pet store, people say, "What a handsome dog! What breed is it?"

You can't determine a dog's breed mix from looks alone. But DNA can tell you. One way to reveal what's in your dog's DNA is with the Canine Heritage Breed test. You order the kit, take a quick swab inside your dog's mouth (just like you see in forensics shows on TV) and mail it in. A few weeks later, you'll get a certificate telling you what your mutt is made of. If you upload a photo, they'll put it on the certificate. The Canine Heritage test is just one of several options available. Ask your vet for recommendations if you'd like to consider testing your pet.

The results will show up in three categories Primary, Secondary and In the Mix.

If your dog has a strong match to a specific breed (one parent was a purebred) you'll see results in the Primary category. Most mixed breeds – if there's been a lot of mixing in the lineage – won't show any Primary results. There has to be 50% or more of a breed represented to show up in this category. Here is a complete list of dog breeds.

The Secondary category will show what breeds have a strong influence on your dog, and each of these will represent less than 50% of your dog's DNA.

In the Mix identifies breeds that have the least amount of influence on your dog's composition, but are still enough to be measurable.

A doggie DNA test can do more than satisfy your own curiosity about your dog's mix of breeds. It can also help you understand your dog a little better. And it may also help your veterinarian in caring for your dog's health, because some breeds are more susceptible to certain health conditions.

A dog's breed has a lot of influence on his needs and behavior. For example, Beagles tend to be friendly, playful and curious. But, they also are at risk for obesity. If your dog has a lot of Beagle in his lineage, you will know to be especially careful to monitor his food intake, and make sure he gets plenty of exercise to keep him in good body condition.

Dachshunds tend to be very loving and affectionate, often becoming very attached to one family member. But, they may not be so friendly around strangers or small children. If there's significant Weiner Dog in the mix, he may need more socialization training to be comfortable around other people.

Boston Terriers are very gentle and well mannered. They are also very affectionate and crave your attention, so much so that they can suffer separation anxiety when you're gone. They hate to be alone. If your dog has a lot of Boston Terrier in him, and you leave home all day, he may need another pet in the house to keep him company.

Obviously, when you adopt from a shelter, you can only guess your dog's breed or mix of breeds. You're going to love your dog no matter where he came from or what he's made of. But, if you do know what breeds are influencing his needs and behavior, you can make sure you're creating an environment at home that's going to work out best for both of you.

To learn about the personality and behavior of the breeds in your dog's mix, check out the petcentric Dog Breed Library.

Watch three mutts get their cheeks swabbed at the dog park and learn the results of their DNA tests.

To learn more about Doggie DNA tests and to experience a fun online pet community pet, visit petcentric.com, brought to you by Purina.