- Not a substitute for professional veterinary help.
Not to brag, but my cat Lily is pure magic. She rides on my shoulder, chats with me in kitty chirps, and brings me the most thoughtful gifts, like that odd sock that fell behind the sofa. She plays fetch and (usually) comes when I call her. She has short hair, blue eyes, a white coat with brown spots, and is the tallest cat on the block.
Lily is the best, and I’d love to know where she came from. I mean, I found her at the Humane Society, but, like, where did she really come from? How did I find such a great cat?
In the past year or so, a few companies have started offering affordable cat DNA tests. Could this be the answer to Lily’s magical origins? The tests promise to reveal a cat’s breed(s), closest wild cat relatives, risk of disease, country of origin, and cues about her coloring and coat type.
I’m a skeptic when it comes to commercial scientific tests, and I happen to be a skeptic with a graduate degree in molecular evolution, a.k.a. DNA science. As much as I would love to know those things about my Very Best Cat, those claims made my whiskers twitch a bit. I wanted to really dig into the science…should I throw down $100 to learn more about my cat?
Dog DNA tests have been around longer than cat DNA tests. They’re similar but not the same, and the reason has a lot to do with the history of how cats and dogs were domesticated.
The relationship between people and our pets is ancient. Dogs were the first animals to be domesticated by humans, somewhere between 14,000-40,000 years ago. Cats started hanging around with people about 8,000 years ago, but the domestication process was much more gradual.
Dogs were selected for their ability to perform specific tasks, such as guarding, shepherding, and companionship. Selective breeding for the physical and personality traits led to the development of dog breeds, which began very early in the relationship between humans and dogs, more than 10,000 years ago.
We actively domesticated dogs. Cats…not so much
Dog breeds are genetically different from one another—this is seen in their ability to “breed true” (pass down the same characteristics from generation to generation) and is supported by recent studies on the genetics of dog breeds. When we talk about mixed breed dogs, we are talking about dogs whose ancestors were purebred dogs.
But cats are different. Once cats started living alongside humans about 8,000 years ago, people eventually started to take cats along when they moved to new settlements. We benefitted from the companionship and hunting skills that helped keep pest populations down, but we didn’t actively select them for certain traits. Cats essentially domesticated themselves—friendly cats gravitated toward people while less sociable individuals preferred more distance.
So, unlike dogs, cats were not bred to do a variety of jobs, and so most don’t have a distinct breed to speak of. As evolutionary geneticist Eva-Maria Geigl explained to National Geographic, “I think that there was no need to subject cats to such a selection process since it was not necessary to change them. They were perfect as they were.”
Cat breeds are a relatively new development
Although some breeding for tabby markings happened in the 18th century, according to National Geographic, the development of distinct cat breeds that have specific physical and personality traits began about 150 to 200 years ago—not long enough for genetically robust differences to exist—when breeds like Abyssinian, Persian, and Maine Coon were developed.
These days there are 42 cat breeds recognized by the Cat Fanciers’ Association, and 80% of breeds are only 80 years old. Cats with breed descriptions such as “domestic shorthair” and “house cat” do not have purebred ancestors, they look and act just as their ancient ancestors did, and they have nearly identical genetics.
The term “mixed breed” cannot be applied to dogs and cats in the same way
Mixed breed dogs result from the mixing of established breeds, whereas domestic shorthair cats have never been part of an established breed—they’re the original ancient domestic cat.
But cats do have some genetic markers
It’s no surprise that 8,000 years of domestication have left some genetic footprints in domestic cat populations. Recent studies have found that modern domestic cats originated from Egyptian cats, and began to spread throughout Europe, Asia, and Africa about 1,000 years ago.
Since then, genetic markers have shown that there are distinct groups of cats in four geographic regions: the Mediterranean basin, Europe/America, Asia, and Africa.
Cat DNA tests claim to measure traits that can help identify your cat’s breed history (which we’ve already explained might be difficult to do), wild cat relatives, disease risk, country of origin, and guesses at her coloring and coat type.
Using a kit provided by the company, you put a swab into your cat’s mouth for three seconds. Or probably 0.3 seconds in Lily’s case, as her vet often refers to her as “spicy.” Do your best to dampen the swab with saliva and then send it off to the lab.
The lab will do its thing. I really wish more information was available on exactly what assays are run because knowing which genetic markers are used is essential to understanding the results. However, as an unregulated industry, they have no obligation to reveal trade information.
Let’s say I send Lily’s cheek swab sample off to the DNA lab. What information will I get back?
The answer is more complex than I expected. To really understand what cat DNA tests can and can’t tell us, we need to understand what questions the tests are asking. So I tried to figure out the real questions being asked.
DNA test question: What breed of cat is Lily related to?
The real question: “What breeds of cats were developed from the same gene pool that my cat comes from?”
It’s easy to assume that a test for breed similarity in cats is the same as in dogs, but it isn’t. With dogs, the question is “What mix of breeds resulted in my dog’s unique genetics?” But with domestic cats, about 90% have no purebred bloodline at all.
The real question I’m asking is not about who Lily’s grandparents are, but who Lily’s far-removed cousins are. I’m asking: Have cat breeders developed a breed from a cat that’s a close or distant relative in Lily’s enormous cat family? Lily would share genes with that breed because they come from the same huge family, not because Lily is the grandkitten of purebred royalty.
DNA test question: What is Lily’s country of origin?
The real question: “What geographic regions are home to your cat’s closest relatives?”
Each cat DNA lab has its own database of sequence data collected from cats around the world. They compare a sequence of your cat’s DNA and determine which cats are the closest matches, and what regions those cats are from.
Of all the tests described, this one seems the most straightforward to me; I have done similar analyses with plants and insects. But I sure would like to know what genetic markers they’re using.
DNA test question: Which wild cat is Lily’s closest relative?
The real question: “Which wild cat has a genetic marker that has randomly ended up most similar to Lily’s?”
The Wild Cat index offered by Basepaws is some cute fluffy genetics. It’s kind of like rolling dice and pairing Lily up with a tiger or snow leopard based on the roll. This is because DNA accumulates random mutations over time. If Lily has the most random changes in common with a jaguar, Lily joins Team Jaguar. It does not mean anything about Lily’s behavior, appearance, or heritage.
As the Basepaws website describes it, “In this case, your cat’s genetic similarity is due to random chance. Your cat’s ancestors just happened to inherit more DNA in common with their wild cat relative than did other cats.“
You could do the same test for yourself or your goldfish and find out if you’re on Team Lion or Team Sand Cat.
DNA test question: Is my cat at risk for a genetic disease?
The real question: “Does my pet have a genetic marker that is statistically associated with an inheritable disease?”
Let’s break this question down.
First, let’s be clear that a screen for genetic factors associated with a disease is NOT a genetic test for the presence of the disease. If your cat has a marker that is linked to the presence of disease in other cats, this does NOT mean that your cat has or will have that disease. The test could essentially be asking, “Does this cat have a marker that appears in cats with feline diabetes, even though we don’t understand how or if the marker is related to the cat developing diabetes?”
Am I splitting hairs here? Absolutely. That’s what scientists do.
My concern is that if the test tells me that Lily has a marker for feline diabetes, I will lose sleep worrying about her health. But I simply won’t know if the marker indicates a significant health risk. My vet might not know, either.
Cat DNA tests are still in version 1.0. “Most of these tests are based on small, underpowered studies. Neither their accuracy nor their ability to predict health outcomes has been validated. Most vets don’t know enough about the limitations of the studies, or about genetics in general, to be able to advise worried owners,” write Lisa Moses and her coauthors in the journal Nature.
Please don’t worry yourself sick, or invest in expensive veterinary care, if you aren’t confident about what exactly the test results mean.
At this point, cat DNA tests are marketed as a novelty and intended to satisfy curiosity about the origins of our pets. As Anna Skaya, CEO of Basepaws, described it in a recent interview on the Cattitude podcast, “You can find out if your mixed breed cat is closer to a Maine Coon, or has some similarities with a Persian…We really want to help the pet parent bond closer to their pet.”
For the price of a pretty nice pair of shoes, around $100, you can contribute your cat’s DNA to a growing data bank of cat genetic sequences.
You’ll get some cool info about where on earth your cat’s ancestors lived, and you might even get some information on your cat’s health. You’ll be joining a growing community of cat lovers who are contributing to the understanding of cat genetics. Depending on what service you use, you might get future updates that give you more information as their database expands and improves.
But buyer, beware.
Some of the claims that cat DNA labs are making are exaggerated. Importantly, the industry is unregulated, and the conclusions that commercial labs are presenting as fact have not been reviewed by scientists outside of those companies.
In an excellent review article about the current state of DNA testing for pets in Nature, Moses and her coauthors warn against what they call “the untamed wilderness of pet genetic testing.” They write, “Done right, the use of genetic testing in companion animals could be a powerful way to better connect people to the possibilities of genetics for treating disease. Done wrong, it could erode trust in science for an increasingly skeptical public.”
If your cat has a serious health problem, she might be eligible for free genetic testing.
Cat DNA companies are interested in understanding the genetics of cat disease, and some are offering free services in exchange for DNA samples from cats who have been diagnosed with feline diabetes and other serious conditions. Check the companies’ websites for more information.
I’ll admit that I’m tempted, because I’m interested in watching the cat DNA industry advance beyond version 1.0 to a more sophisticated scientific endeavor. And if Lily’s DNA is included, I’ll be more invested in that information.
Will my curiosity about her mysterious genetics overcome my skepticism? I’m still thinking, and Lily made the excellent suggestion that we sleep on it.