Your Dog’s DNA: What Can Dog DNA Tests Really Tell You?

At some point in our life with dogs, many of us may have wanted to find out more about our furry friends and ordered a dog DNA test in the hopes it would reveal more about our dog’s breed, susceptibility to health or genetic conditions, and behavioral traits and personality. The results can trigger everything from surprise to relief to ambivalence to panic. Yet the question remains, how accurate are these tests?

The History of Dog DNA Kits

The two leading companies in the canine DNA testing market are Wisdom Panel from the Mars Corporation and Embark. Mars became a pioneer in the field of consumer pet genetics with the 2007 launch of their canine DNA kit “Insights,” based on veterinarian-collected blood samples. Two years later, they rebranded their test as Wisdom Panel, which allowed for the collection of cheek swabs for testing, thus eliminating the need for a veterinarian to draw a blood sample. In 2016, Embark began offering its dog DNA test kit to the public.

A multitude of other companies have followed in the footsteps of Mars and Embark in developing and selling their own canine DNA test kits to the public. Many of these companies also market specialized tests for determining age, specific health conditions, breed-specific conditions, allergy, food and environmental sensitivity, and sibling DNA; in addition, some firms target only veterinarians or breeders.

How Do Dog DNA Tests Work?

First, let’s go back to basics: a cell’s nucleus is where DNA “lives.” A tremendous amount of genetic information is stored inside that single cell, comparable to some 1.5 gigabytes of data.

Each dog inherits two copies of each gene, one from each parent. The genes are made up of four chemical bases represented by the letters A, T, C, and G, which combine to create the unique characteristics of an individual dog. These letters are always matched; the rules governing this matching allow a laboratory to interpret the dog’s DNA, which in turn enables them to identify the dog’s breed origins as well as health indicators.

For dog genetic testing, the laboratory looks for DNA mutations, which is anything in that gene that affects how it functions. These mutations can completely obstruct a gene, which often leads to disease, or can simply alter the gene’s function to produce a slightly different trait, such as a change in coat color.

Genetic tests generally produce three possible results:

• Clear/Unaffected/Normal: The dog has no copies of the mutation that causes disease or coat changes.
• Carrier: The dog has one normal copy and one copy of the mutation, and which may affect the dog differently depending on whether the mutation is dominant or recessive.
• Affected/At Risk: The dog carries no normal copies, and two copies of the mutation.

The Role of DNA Tests in Determining Your Dog’s Breed

DNA test results can include breed mix, family tree, and heritage up to three generations. By comparing your dog’s DNA with a database of different breeds, the lab can report which breeds are the closest match.

Many dog guardians order DNA tests simply out of curiosity: how “pure” is your purebred? If your pup is a mixed breed, what breeds have gone into that mix? Genetic tests can reveal the percentage of specific breeds in your dog’s genetic makeup, which help explain her appearance: large or small, short legs or long ones, floppy ears or pointed ones, a long soft coat or wiry one, a boxy head or tapered one, future size and weight, and more.

Different breeds are inclined to exhibit certain traits, energy levels, and have temperamental tendencies, all of which can be revealed in a DNA test. For instance, herding breeds like Border Collies and Australian Shepherds usually require more mental stimulation and are extremely active while large breeds like Great Danes and Mastiffs tend to have joint issues. A breed DNA test can help caregivers personalize their training and exercise routines, be on the alert for health issues, and provide specialized nutrition, grooming, and care.

The manufacturers of these DNA tests claim over 90% accuracy, but because none of them are independently verified, the preciseness of these numbers is somewhat questionable. Most companies require purchasers to send along a photo of their dog, so in one study, researchers intentionally switched photos when they submitted the tests. The upshot was that one company provided an “official analysis” that the dog—actually a Chinese Crested—was part Border Collie and part Golden Retriever, which is what anyone looking at only the photo might have guessed. In a separate case, a sample was collected from a registered Great Dane; the results from one company said the dog was part Staffordshire terrier, and another labeled her as 100 percent chihuahua.

What DNA Tests Can Reveal About Your Dog’s Health

One of the biggest questions about DNA testing involves identifying potential health risks. However, it’s important to remember that even if your dog has a variant for a specific genetic health risk or condition, it doesn’t mean they will develop that condition.

In fact, the same genetic variants can affect different breeds in different ways. A mutation might be highly likely to cause a genetic condition in one breed, but that same mutation might only rarely cause the same condition in another breed. Also, the likelihood of developing a genetic condition can vary within a given breed as well. (One more reason to always consult your veterinarian about genetic health risks.)

The bottom line is to not panic if test results say your dog has a genetic predisposition for a certain disorder: predisposition doesn’t mean certainty. Talk with your veterinarian about the report and discuss what, if anything, you—and they—can do to mitigate any future effects of your pup’s genetic makeup.

That being said, there are some things in a genetic report you need to pay special attention to and immediately bring to your vet’s attention. One of them is if the report says your dog has the Multidrug Resistance 1 (MDR1) gene. This genetic variant can put dogs at risk of severe or life-threatening complications after taking specific medications at specific doses.

Some disease-related genetic tests are breed-specific. An example is a genetic mutation in Dalmatians where the concentration of uric acid in the urine causes them to form bladder stones, necessitating surgery to remove them.

Many medium- to large-sized dog breeds such as Irish Wolfhounds, Newfoundlands, Great Danes, and Dobermans have a genetic predisposition to develop dilated cardiomyopathy, a life-threatening heart disease. Studies suggest that as many as one out of every two Dobermans risks inheriting this disease. Another genetic condition linked to Dobermans is Von Willebrand’s Disease, a blood clotting disorder that puts these dogs at risk for severe hemorrhage even during simple surgery. Genetic testing can also reveal if a dog is at risk for developing Progressive Retinal Atrophy (PRA), which causes blindness in older dogs; almost a dozen breeds are prone to developing this disease. There is even a genetic test that screens for the risk of cranial cruciate ligament (CCL) rupture in Labrador Retrievers.

It’s important to remember that gene expression relies on factors other than just genes, including environment, nutrition, lifestyle, and cellular metabolism. At the same time, while studies show that some conditions—for instance, hip dysplasia—may be inherited, multiple genes contribute to its development, and these genetic factors interact with environmental influences. Studies have shown that heritability estimates for hip dysplasia range from 20% to 60%, depending on breed.

What To Do About Your Dogs DNA Test Results

This brings up the question of how we as dog guardians should respond to genetic test results related to our dog’s health and/or predisposition to a disease or disorder. While genetic tests can be helpful and have the potential of improving a dog’s health, there’s a real danger when people interpret test results without consulting a veterinarian, and go on to make emotional decisions about diet, exercise, lifestyle, or even such drastic measures as euthanasia without fully understanding the nuances of the report. If your dog’s test raises concerns, it’s important to talk to your veterinarian and work with them to make the best, most informed decisions possible for your dog.

How Accurate Are Dog DNA Tests?

As discussed above, sometimes dog DNA tests are quite accurate. Other times, not so much. A recent study shows that claims about genetic links to behavior are both overhyped and misleading. The study tried to reproduce earlier research linking 151 genetic variants to dog behavior but after controlling for breed and individual traits, researchers found that none of these genetic variants actually predict behavior, but were instead related to the breed-related physical traits. What had been labeled behaviorally predictive genes were simply genetic markers related to breed. Some of these previously purported “behavior genetic variants” were linked to genomic regions associated with coat color, ear shape, and height, among other breed-defining physical characteristics. Further studies showed that inherited behavioral traits are far more rare than aesthetic traits, suggesting that attempts to predict the behavior in individual dogs using genetic information alone may be quite inaccurate.

That being said, the results from testing companies are usually fairly accurate. What accounts for discrepancies when they occur? Often, it’s the database that each company maintains, since each one uses a private, independent DNA database for comparison and breed determination. Another issue is the industry’s lack of standards, transparency, and regulatory oversight. Unlike with human genetic testing facilities, animal genetic testing is not regulated, and companies are not obligated to disclose their methodologies.

As genetic testing becomes more common and more affordable to the general public, it’s essential that the industry develop and implement standards, so as to build trust within the veterinary community and the public and unlock the exciting animal health benefits that genetic testing offers.