Dog and Cat Genetics: Everything You Need to Know

5 min read

By Monica Weymouth

As pet parents, we like to think that we know everything about our companions. We know exactly where to scratch our pup’s ears and exactly where to look when sneakers go missing. We make sure kitty’s preferred windowsill is clear for afternoon naps and we would never dream of switching up her favorite dinner.

But how much do we really know about what makes our pets, well, our pets? Understanding our cats’ and dogs’ DNA can not only help us understand their endearing quirks, but it can also help us raise happy, healthy BFFs.

Pet DNA, Now and Then

It’s been around 10,000 years (and maybe as long as 30,000 years, according to some) since man met his proverbial best friend and thousands of years since cats and humans first cuddled up. Even so, on a molecular level, our modern-day pets are still surprisingly similar to their wild counterparts. A 2013 study showed that your lap cat shares 95.6 percent of its DNA with a tiger—something to keep in mind the next time kitty is stalking through the house. Canines, as it turns out, are even more closely related to their wild cousins.

“Evolutionarily, domestic dogs are closer to wolves and coyotes than domestic cats are to the great cats—tigers, lions, leopards and cheetahs,” says Jerold Bell, DVM, professor of clinical genetics at Tufts University. “Dogs can reproduce and produce living offspring with their wild cousins, while cats are too distantly related to be able to reproduce with the great cats.”

However, while wolf-dogs and coy-dogs may be possible, don’t start looking for one to bring home—when it comes to DNA, a percentage point or two is significant. Illegal to own as pets in many states, these hybrids pose significant behavioral and health challenges and are frequently turned over to shelters and sanctuaries.

Nature Versus Nurture

When was the last time you saw a Jack Russell lounge his way through a Saturday? Or a Shih Tzu get his precious little paws dirty? It’s no coincidence that breeds tend to share some predispositions, as genetics play a large role in the personality of our pets.  

“Different dog breeds were developed based on ancient behaviors of hunting, guarding, hearing, scenting and protection, and have different innate and inherited behaviors,” explains Bell. “Research confirms the notion that calico and tortoiseshell cats can have a more ‘fiery’ temperament. This can show as a greater propensity to hiss, chase, or lash out.”

With this in mind, it’s important to do some breed research before adding another member to your family—a puppy training class won’t necessarily overrule innate instincts.

“The power of genetics in determining canine temperament is particularly obvious in working breeds, such as the Border Collie,” says Casey Carl, DVM, associate medical director of Paw Print Genetics. “For hundreds of years, humans have selected Border Collies with the best herding skills to be the breeding stock for future generations. This has led to the creation of a profoundly intelligent breed in which puppies, sometimes as young as two or three months old, begin showing early signs of herding behavior without any training.” And while this herding behavior is highly desirable on the farm, it may prove less so if you live in a small, urban apartment.

While genetics has a hand in many tendencies, pet parents also play a large role. “Like humans, the temperaments of dogs are heavily influenced by both genetic and environmental factors,” adds Carl. “Though each dog is born with certain behavioral genetic predispositions, life experiences, particularly early life experiences, play a very important role in how these predispositions end up manifesting in the adult dog.”

Coats of Many Colors

What’s the difference between a tabby cat and a ginger kitty? Or a yellow lab and a black? In a word, genes.

With dogs, many breeders test their breeding stock for genetically determined coat characteristics to produce puppies with desired qualities, from curly blond locks to sleek brunette tresses.

According to Carl, there are at least four genes that determine color and over a dozen different genetic mutations that have been associated with the patterns, hair length, hair curl, texture and even shedding characteristics. “In addition,” he said, “it is suspected that there are still many undiscovered genetic mutations which contribute to the coat characteristics we have selected for.”

Curious as to where your cat got his good looks? Tests are also available to determine the genes at play in feline coat colors and patterns.

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