Genetic Testing for the Mixed Breed Dog
Yesterday, we talked about how genetic and other types of tests can help breeders make informed decisions about which individuals should be bred and which should be spayed or neutered to prevent them from passing on "faulty" genes to the next generation. Since December 2nd is National Mutt Day, I thought I’d talk about whether or not mixed breed dogs are also candidates for genetic testing.
Until recently, I think the words "genetic testing" and "mutt" rarely were found in the same sentence. All of our genetic tests were essentially aimed at ferreting out diseases that were prevalent within particular breeds with the primary aim of making subsequent generations healthier. Why test a mutt who shouldn’t be bred in the first place, and what tests would your run even if you wanted to? It is notoriously difficult to determine the heritage of a mixed breed dog unless the mating was witnessed. Of course, this doesn’t stop veterinarians, shelter personnel, friends, family, and random passers-by on the street from guessing, but that’s basically all they are … guesses.
I saw an article a couple of years ago (I can’t find it for the life of me; if anyone can pass on a copy it’d be greatly appreciated) that showed how bad we so-called animal professionals were at identifying breeds. I don’t remember the statistics, but the take home message was what we call a lab/pit mix might very well be a boxer/Australian shepherd cross.
Things have changed recently with the advent of DNA dog breed analysis, however. Several companies have come up with their own systems, but they all operate on similar principles. You gently swab the inside of your dog’s cheek to remove loose cells that contain DNA. The swab is then sent to the lab where the DNA is extracted and compared to a database of samples from a long list of dog breeds. The closest matches are your pet’s nearest relatives. The tests aren’t perfect, all breeds of dogs aren’t represented in each of the companies’ databases for example, but the results are more reliable than a guess based solely on a dog’s appearance or behavior.
Why run a dog breed analysis on your mixed breed dog? Curiosity is the primary reason. It can be fun to be able to answer "what type of dog is that" with a reasonable degree of certainty.
Theoretically, you also might be able to use the information to predict what health problems could be in store for you mutt. For example, both German shepherd dogs and golden retrievers are at risk for degenerative myelopathy. If you knew that your mutt was primarily a mix of these two breeds, this disease should be on your radar screen as he ages. Individual variation and the complexities of genetics make these types of predictions sketchy at best, but if you want to know what your dog "is" anyway, you might as well do a little research into how his genetics could affect his health.
Dr. Jennifer Coates