Inside dog DNA testing: Myths, insights, and health benefits with Dr. Jenna Dockweiler, DVM, DACT of Embark
In the world of pet health and care, DNA testing for dogs has opened new possibilities for understanding a pet’s lineage, predicting health risks, and discovering traits. But with these advancements come common misconceptions and unanswered questions.
To clarify the truth about dog DNA testing, we spoke with Dr. Jenna Dockweiler, DVM, DACT, a Senior Professional Services Veterinarian at Embark. Dr. Dockweiler is a practicing veterinarian, a board-certified theriogenologist (specialist in animal reproduction), and a certified canine rehabilitation and veterinary acupuncture therapist. With her deep expertise, she helps shed light on the nuances of genetic testing for our four-legged friends.
Throughout this interview, Dr. Dockweiler shares invaluable insights into the benefits of dog DNA testing, its limitations, and the innovative technology Embark brings to pet parents. So, whether you’re a new pet parent curious about your dog’s ancestry or looking to proactively manage your pet’s health, you’ll learn a lot from our chat with Dr. Dockweiler!
What common myths or misconceptions do you encounter about dog DNA tests? Why do these myths persist, and how do you address them?
“The most common misconception we encounter about dog DNA testing has to do with the appearance of mixed-breed dogs. Visual breed identification is notoriously unreliable, and even shelters and veterinary staff guess incorrectly up to 90% of the time. This is because less than 1% of a dog’s 20,000 genes impact their appearance, so trying to guess a dog’s breed mix based on how it looks rather than its genetic material is very difficult. There is so much variation among dogs in general that visual or behavioral ID is generally an unreliable way to determine a dog's ancestry. As an example, many mixed-breed dogs that have a large percentage of Golden retriever ancestry have a black coat color.
When we start to mix breeds, it can be helpful to think of the mixing of genetic material as taking a bunch of fruit and making a smoothie instead of a fruit salad. That means it isn't necessarily a piecemeal hodgepodge of traits that you can pick out from each breed, but rather a blend of traits that come from complex interactions between different parts of the genome that determine what the dog looks like. There could even be traits that are determined by a single mutation that you could see in a mixed-breed dog that comes from a breed too far back in their family tree to detect with a DNA test. While you can make some general inferences about things like body size, two dogs with similar mixes may actually look quite different depending on which parts of their genome were inherited from which breed or population.”
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How accurate are dog DNA tests in identifying breeds, and what factors can affect this accuracy? Could certain breeds or genetic markers be harder to detect?
“Our testing platform here at Embark is a customized Single-Nucleotide Polymorphism (SNP) Microarray, developed in collaboration with Cornell University College of Veterinary Medicine. It utilizes the latest research-grade canine genotyping technology. This advanced platform enables the analysis of thousands of genetic markers, allowing for a comprehensive evaluation of a dog's breed composition, traits, and potential health risks with 99% accuracy. To determine breed ancestry, we look at long stretches of the genome in dogs of known breeds from our reference panel. When we see identical long stretches of DNA in two different individuals, this means they were inherited from the same, somewhat recent, ancestor. If we add up all the stretches of DNA that match perfectly to one and only one breed, we are able to identify how much of their DNA must have been inherited from that breed. We then do this for any other breed found in the dog, and from all that, we can understand what percentage of the dog's ancestry came from each breed. It’s important to note that a DNA ancestry test cannot determine purity. This is because purebred status is not itself a scientific designation. It includes human-defined registration status and pedigree records indicating all of a dog’s ancestors were of the same breed but does not require an examination of their genetic material.
Consequently, individual dogs registered as purebreds can (and sometimes do) display ancestry from a few different breeds. Usually these DNA signatures come from closely related breeds, likely used before the breed registry closed the stud book. Importantly, these genetic results do not affect registration status in any way. Surprising as it may be, genetic ancestry and purebred status are two separate considerations. Certain breeds or varieties that have a high amount of genetic variation or landrace breeds (dog breeds that developed over time to adapt to their environment, rather than from human selection) can be trickier for a DNA test to detect.
Embark is the only DNA testing company able to detect Village Dog ancestry. Village Dogs are free-ranging, free-breeding dogs whose ancestors were indigenous to a geographic area. In effect, they are the descendants of the founding population of dogs in a region. Embark's co-founders have studied Village Dogs on six continents since 2007 in their efforts to understand the history, traits, and health of the domestic dog. Through this work, they have discovered the origins of the dog in Central Asia, and they also identified genetic regions involved in domestication and local adaptation.”
Can a DNA test really predict a dog’s behavior or temperament? To what extent is personality influenced by genetics vs. environment?
“The genetics of behavior in all animals, including dogs, is complex. While some genes have known associations with behaviors (such as the mutation in the POMC gene affecting food motivation in Labrador Retrievers), the genetic basis for many behaviors like herding, pointing, retrieving, etc., are still being studied.
From testing hundreds of thousands of mixed-breed and purebred dogs, we’ve learned that it isn’t uncommon for dogs of diverse ancestries to exhibit what many people think of as breed-specific behaviors or traits. Some toy breed mixes might point at birds, and some terrier mixes may have strong retrieving instincts. A purebred Labrador may hate swimming, and a purebred Pug may excel at scent work. It’s important to remember that all dogs are individuals, and their behaviors result from very complex genetic and environmental interactions that may or may not be consistent with their breed or breed mix.
It’s also important to remember that behaviors like herding and pointing were intentionally selected for over time in different breeds. We likely wouldn’t have these behaviors in purebred dogs today if they didn’t exist at some frequency in the general dog population. Embark is on the cutting edge of canine behavioral research to learn more about why dogs act the way they do.”
How can dog DNA testing benefit a dog’s health beyond just knowing their breed? Are there specific health risks or preventative measures a test can reveal?
“DNA testing can tell us a wide variety of information about an individual dog. Importantly, we can identify dogs at-risk for known inherited health conditions. While not a diagnosis of disease, knowing about these risks ahead of symptoms offers the best chance to proactively care for your dog and potentially avoid the disease manifesting altogether.
DNA testing can also reveal personalized medicine information, such as MDR1 drug sensitivity. This is a genetic mutation some dogs have that leads to increased sensitivity to certain medications and requires medication changes or dose alterations to avoid an adverse reaction. Dogs with this mutation are otherwise completely normal; the only ways to know if they may have trouble metabolizing certain medications are either to genetically test, or to see if they have an adverse reaction to one of the offending drugs. Obviously, it is much better to avoid a reaction altogether, as these can be life-threatening!”
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Is there an ideal age for testing a dog’s DNA, or can any dog be tested regardless of age? Do puppies and older dogs get different results?
“You can test your puppy at any age since DNA test results will not change as a dog ages. We recommend performing cheek swabs around 4 weeks of age, or when the pups can safely be isolated from mom and littermates for at least an hour before swabbing.”
How does Embark’s database or technology compare with other dog DNA test providers? What unique insights or innovations set Embark apart?
“Embark is the most accurate breed identification test on the market, with over 350 breeds, types, and varieties tested. We are also currently testing for over 270 health conditions and 55 traits, with new markers added as they are discovered.
Our testing platform also offers the world’s first relative finder, and every sample in our database of over 2 million dogs contributes to scientific discovery and helps on our mission to end preventable diseases in dogs. In fact, we’ve made several scientific discoveries, including finding markers for Early Onset Adult Deafness in the Rhodesian Ridgeback, red pigment intensity, and inbreeding depression in Golden retrievers. We are also the only company able to test for Mast Cell Tumor risk in certain breeds. Additionally, we have highly specialized veterinarians and canine geneticists on-staff to support you as you learn about your dog’s results.”
Do DNA tests work for mixed-breed dogs, and how do they identify ancestry in complex mixes? How can owners interpret results that include many different breeds?
“DNA tests absolutely work for mixed-breed dogs, and sometimes the ancestry results can be surprising! Our ancestry algorithm works by finding long identical segments of DNA between an individual dog and the purebred dogs in our reference dataset. These long identical stretches of DNA are more likely to reflect recent ancestry, whereas shorter segments reflect more distant ancestry. When these segments become too short, they are classified as “Supermutt”. This refers to a portion of ancestry that is significantly far back in their family tree and therefore can not be as confidently identified as more recently inherited breeds.”
What are the limits of dog DNA testing—what can it not tell us? Are there questions about a dog’s health or ancestry that remain unanswered?
“As with any testing, there will be a few specific limitations with DNA testing. First, if we don’t know what genetic mutation causes a disease, we won’t be able to test for it. Similarly, diseases caused by multiple genetic mutations or complex interactions of the genotype with the environment are not easily tested at this time (though we are continually working on this problem, and have begun to offer polygenic risk scores for certain conditions - our allergy risk score is a good example).
Second, DNA testing tells us about a dog’s disease risk - it can’t tell you if or when an individual will develop a disease nor what exactly the disease will look like (although we have statistical measures that will help us interpret some of that risk and make predictions).
Lastly, with a few very specific exceptions, we generally can’t tell which dogs are more susceptible to cancer at this time.”
Curious about trying an Embark Breed+Health Test for your dog? You can now get $65 off with code JOYDOGS, valid until 12/12.