Who’s Your Daddy? Doggy DNA Testing

We have always been curious.  As the proud grandparents of two lovable mutts we wondered how they got to be the way they are.  So when we saw the brochure on the vet’s counter for a DNA testing service we jumped at the chance to see what breeds made up our dogs.  In addition to satisfying curiosity, the tests are marketed as an aid in health wellness planning for your dog.  Supposedly, by giving advance notice of some breed’s most likely health problems, you and your vet can construct a better lifetime care plan.

Unfortunately the test results are often not specific enough to answer heritage questions or provide health guidance.

The science behind the tests needs more work.

How it Works
Mars Veterinary has started marketing Wisdom Panel, a test to determine breed mix through local vets.  It involves having the vet taking a blood sample and sending it to the testing lab, which then compared the DNA in your dog against a database of the DNA of 130 “purebred” breeds.  Costs can vary from vet to vet but run in the $150-$175 range.

Metamorphix is another company that has been offering DNA based testing for some time.  They have 38 breeds in their canine heritage database and offer a cheaper and less invasive mouth swab sampling technique that you can do at home.  Sampling kits are ordered from their website and you return mail them to the lab in envelopes they provide.  The cost is about $80.

Although the size of the database varies, the process at both companies are similar.  Their software compares your dog against 100-300 genetic markers and reports it’s findings in three categories.

1. Traces - which may be great grandparent and beyond, and are very small amounts with little influence on behavior and appearance.
2. Secondary - this breed has a strong showing in the DNA mix and is more influential but still makes up less than the majority of the dog’s DNA.
3. Primary - this is the breed that represents the majority of the dog’s DNA makeup.  Having a “primary breed” is rare in a mixed breed dog unless they have at least one purebred parent.  In ten reports we examined covering eight dogs, non had a primary listing.

The point here is that you probably aren’t going to get something as definitive as you would like.  You may well get a listing of traces of 8 different dogs that look and act very little like the one at your feet.  And while not satisfying from a curiosity standpoint it is not helpful creating a breed specific health care plan for your dog - a benefit that both companies tout.

And worse yet…

Test results for the same dog can be markedly different between the two companies!

We were surprised and confused by the very different answers by the two companies for the SAME dogs.

Company Response
Key executives and scientists from both companies reviewed the tests, concluded that the samples were good, that their testing process was good, and both stood by their results.  They have seen these differences before and discussed how it isnot as cut and dry as we might imagine for a couple of reasons:

• First, there is no such thing as a “pure” dog.  The AKC recognized purebreds are actually man made mixes created by controlled crossbreeding to enhance certain characteristics.  So even the DNA of an American Kennel Club purebred is a mix that may vary within limits.
• Secondly the database samples are not perfect.  They are based on good sampling techniques that will improve over time with more samples.
• The software for both companies reports the breeds that have the highest statistical probability of matching the DNA from your dog, not definitive matches.

Both believe that their answers are as good as the science can offer right now.  Wisdom Panel believes their larger database yields better probabilities.  Heritage is expanding their database this spring to include approximately that same number of breeds.  But the truth remains; the tests are someone’s estimation of the probabilities - not the definitive facts that guarantee an understanding of your dog’s behavior or health profile.  The results can be answers that are as different as Daschund and Dane.

Our Recommendation
Don’t test.  Save your money.  Wait until next year and give the industry time to debug itself.  We will try again and report the results.  In the meantime, enjoy your mutts for what you know them to be - good friends and good dogs!

You can save money by reading a good dog book and making your own guesses about your pooch’s heritage, and you may be just as accurate!

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