In recent years, genetic testing for dogs has expanded rapidly, moving beyond breed identification and health screening into the much more emotionally charged territory of behavior and personality. Pet parents are now being told that a simple cheek swab can predict whether their dog is anxious, aggressive, sociable, or trainable.
If you have a mixed-breed dog, it’s fun to speculate about their lineage. Is their drive to dig up your flowerbeds due to a terrier connection? Does she howl because she’s part beagle or husky? While you may be tempted to guess your dog’s breed based on looks alone, this often doesn’t tell the whole story about the makeup of your pooch’s DNA.
Aside from curiosity, it can be useful to know your pet’s background for health reasons. Certain diseases, such as mitral valve disease, and cranial cruciate ligament rupture, are more common in certain breeds. Being aware of heritable diseases that can affect your dog can help you make proactive choices now that help protect their health long-term.
Epigenetics is the reason your rescue dog’s past still whispers to their DNA, even though their genes themselves haven’t changed. Think of DNA as a piano and epigenetics as the hands playing it. Stress, neglect, nutrition, safety, love, routine, and trust don’t rewrite the genetic keys, but they absolutely influence which ones get played loudly and which stay quiet.
A dog who grew up in chaos may have genes activated for vigilance, inflammation, or anxiety, whereas the same DNA placed in a calm, predictable, nourishing home can gradually express resilience, healing, and emotional balance. This is why environment matters so much for rescues. Every walk, meal, cuddle, boundary, and moment of safety becomes a biological signal, gently teaching their cells that the world has changed, and that it’s finally okay to exhale.
A recent study1 using data from Darwin’s Ark, one of the largest community science projects focused on canine genetics and behavior, calls these claims into serious question. Analyzing genetic and behavioral data from more than 3,000 dogs, researchers found no evidence that commonly marketed behavior-associated genetic variants actually predict how dogs behave.
This research highlights a disconnect between what genetic testing companies promise and what current science can reliably support, with important implications for how we understand, train, and care for dogs.
The Promise and the Problem of Canine Behavior Genetics
The appeal of behavior-based genetic testing is easy to understand. Dogs are family members, and behavior challenges can be stressful, confusing, and sometimes heartbreaking. If genetics could offer clear answers or early warnings, many would welcome that insight. However, behavior is one of the most complex traits in biology. Unlike coat color or ear shape, behavior arises from the interaction of thousands of genes, early development, learning, environment, nutrition, social context, and emotional experiences.
The Darwin’s Ark study evaluated previously reported genetic variants that were said to influence behavior, such as fearfulness, sociability, or aggression. When researchers analyzed these variants using individually measured behavioral data instead of breed averages, the associations disappeared. The variants did not meaningfully predict behavior in real dogs living real lives.
DNA Tests From Four Companies Yield Different Results
DNA testing should be an exact science, so a dog should get the same results no matter which company is doing the test. Further, a purebred dog, it would seem, should get DNA results that match its given breed.
To find out if this was the case, a CBC Marketplace test2 was performed that involved two mixed-breed dogs, one purebred dog (a Great Dane) and one human. DNA samples of each were sent to four dog genetic testing companies:
- Wisdom Panel – $150 kit that tests for more than 350 dog breeds and 25 health conditions. It claims to have a more than 98% accuracy rate.
- Embark – This $288 test claims to be the most accurate dog DNA test on the market.
- Accu-Metrics – Also known as Viaguard, this company offers a DNA test kit for $80.
- DNA My Dog – A $100 kit that tested for about 100 breeds at the time of the testing (it’s now up to more than 350). It still claimed to be between 97% and 99% accurate.
All of the companies came back with different results for the dogs. Accu-Metrics’ results included a mix of cocker spaniel, Labrador retriever, Staffordshire terrier and rottweiler, while DNA My Dog came back with bulldog, flat-coated retriever and German shepherd.
How Studies Can Get it Wrong
Many previous investigations relied on breed-average behavior profiles rather than data collected from individual dogs. This approach assumes that all members of a breed behave similarly, an assumption that does not hold up in the real world.
The Darwin’s Ark study found that several genetic variants previously linked to behavior were strongly associated with physical traits like height, leg length, or ear shape. Because certain breeds share both physical traits and stereotyped reputations, those physical markers were mistakenly interpreted as behavioral predictors. Without careful controls, it becomes easy to mistake appearance-linked genetics for behavior-linked genetics.
Behavior Is Polygenic and Shaped by Life Experience
Canine behavior is polygenic, meaning it is influenced by many genes, each contributing a very small effect. Even when genetics play a role, behavior is only moderately heritable. Environmental factors such as early socialization, maternal stress, species-appropriate nutrition, training methods, physical health, and emotional safety significantly influence how behavior develops.
A dog raised in a calm, enriched environment with positive reinforcement will often behave very differently from a genetically similar dog raised under chronic stress or inconsistent care. This reality places a natural ceiling on how predictive any genetic test can be. No test that examines only a handful of variants can capture the complexity of behavioral development, much less override the powerful influence of lived experience.
Both acute and chronic forms of stress can take a toll on your dog’s health. When the stress is prolonged, it’s associated with shortened lifespan and can also increase your dog’s susceptibility to infections. Wound healing is also slowed in response to stress, while stomach ulcers and inflammatory bowel disease may be exacerbated.
When dogs are supported with species-appropriate nutrition, daily movement, and emotional safety, their bodies are capable of remarkable repair even in the face of injury or chronic disease. Omega-3 fatty acids (DHA and EPA) also play a critical role, decreasing inflammation, influencing pain perception, modulating neuroinflammation, and regulating synaptic signaling. Research has documented how omega-3 supplementation plays into brain development, and can improve pain control and quality of life in dogs with musculoskeletal injuries and degenerative joint disease3.
Dogs living with the stress of fear and anxiety disorders may also have shortened lifespans, while stress from separation anxiety is linked to increased skin disorders. As in humans, however, it’s likely that stress affects individual dogs differently, with some being more sensitive than others. Dogs with bold personalities, for instance, have been found to stave off diseases better than shy dogs, even when coping with a highly stressful environment. You can also play a role in how well your dog responds to and copes with stress by offering fear-free tools to help with calming.
Why This Matters for Dogs and the People Who Love Them
Misinterpreting genetic data risks labeling dogs in ways that can influence how they are treated, trained, and even rehomed. When a test suggests a dog is genetically predisposed to aggression or anxiety, that can shape expectations, reduce patience, and increase fear-based decision-making.
In shelters, such labels could contribute to reduced adoption chances for certain dogs. From a welfare perspective, this is deeply concerning. Dogs’ behaviors are fluid, responsive, and capable of change. Overreliance on unvalidated predictions undermines that truth and can distract from true interventions that help dogs thrive.
Potential Benefits of Genetic Screening
Canine genetic testing has value. Genetic screening for well-characterized inherited diseases can be extremely useful when supported by strong evidence and large datasets. The first thing I tell proactive pet parents to do after rescuing a “mutt” is to consider a DNA test for disease conditions, because supporting known genetic predispositions before they epigenetically express themselves is so much easier to address (and prevent) than waiting until disease occurs.
However, even in the realm of disease prediction, complex conditions involving multiple genes and environmental triggers face similar limitations to behavior prediction, such as hip dysplasia. Meaningful genomic predictions for complex traits require large cohorts of dogs with carefully measured individual phenotypes, not breed stereotypes.
As an integrative veterinarian, I believe this kind of research is a powerful reminder to approach canine behavior with humility and compassion. Dogs are shaped by biology, yes, but also by their history, lived experiences, relationships, routines, sense of safety, and capacity for trust. No swab can measure resilience, curiosity, or the quiet healing that comes from consistency, patience, and being deeply understood. Rather than asking what genes can predict, a better question may be this: what do our canine companions need right now to feel safe, supported, and truly seen?
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About Karen Shaw Becker, DVM, CVH, CVA, CCRT
Veterinarian Dr. Karen Shaw Becker believes biologically appropriate food and an animal's immediate environment are essential in determining health, vitality, and lifespan. She has spent her career as a wildlife and exotic animal veterinarian and small animal clinician, empowering animal guardians to make intentional lifestyle decisions to enhance the well-being of their animals.
