Signup for The Your Dog Flash

Latest health and behavior news and advice from the veterinarians at Tufts University.

Features April 2017 Issue

Ancestry.com for Your Dog?

On having your mutt tested to learn the breeds she’s comprised of — and the diseases she’s prone to.

Dog sleeping

© pudding | Bigstock

When veterinary geneticist Angela Hughes, DVM, PhD, picked up her stray, whom she named Annie, from the street, she had her new pet’s DNA analyzed to learn which breeds the dog was descended from. Learning that Annie is 50 percent Russell terrier and 25 percent cattle dog helped Dr. Hughes understand her dog’s behavioral inclinations and gave her a handle on how best to train her.

“What kind of dog is that?” It’s hard to go to a dog park and never hear that question being posed. We love to know the breed, or breeds, of a particularly cute or interesting-looking dog whose features have us stumped. Indeed, we often wonder about the breed makeup of our own mutts.

“Well, we think she’s part beagle and part schnauzer,” you might hear (or say), or “I don’t know — people have said she looks a little like a vizsla.”

Well, now you can learn the answer — at least up to a point. There are companies out there that for $100 or so will perform a DNA test on your dog. All you need to do is brush the inside of your pet’s cheek with a little bristle brush, place some scraped-off cheek cells in a box sent to you by the company, and ship them off to a lab.

Which lab is best?

There are a number of companies that perform DNA testing on dogs to find out the breeds from which they are descended. The company that has done the most research in the field, says Tufts veterinary geneticist Jerold Bell, DVM, is Mars, Inc. Yes, the manufacturing giant that brings you 3Musketeers, Dove Bars, and m&ms also has a huge animal health division. (They make a number of dog food brands, too, including Royal Canin and Iams, and own many veterinary hospitals.)

“They’ve taken literally thousands of samples from purebred to mixed-breed dogs and broken down the DNA and breed signatures,” Dr. Bell says. “A couple of other entities have done it as well but not to the same extent. Most are just taking the published results of others, then just setting up a lab and using the published data” to arrive at results. “If a question comes up, they don’t have the background to deal with it. They don’t have the repeatability of results, the specificity.” A noted exception is Embark, a research partner of Cornell University’s College of Veterinary Medicine. They were not out in front on the testing, but they do a good job, with a testing package that differs a little from the ones offered by Mars. (More on that in a bit.)

Whichever company you might want to use, Dr. Bell states that having your mixed-breed dog tested to see what breeds she comes from “is still primarily a novelty type of thing to do.” It’s not yet in the mainstream of what dog owners seek. But that may start to change.

What you will learn from DNA Testing

Generally speaking, testing of mutts does not give you a perfect pie chart: 32 percent Labrador retriever, 27 percent collie, 19 percent West Highland terrier, 12 percent Husky, 7 percent Dachshund, and 3 percent golden retriever. If you are talking about the offspring of two purebred dogs, then yes, Dr. Bell says — results are going to be extremely accurate. Even going back to four purebred grandparents or eight purebred great-grandparents, you’ll get a very good understanding that Fido inherited a lot of genes from Grandpa Max on his sire’s side but few from Great-Grandma Lottie on his dam’s. “But beyond that,” Dr. Bell says, “there’s a lot of mixture and sharing of genetic markers between breeds that really muddies the water. A lot. So if you go back at least three generations” and don’t know the breeds of the great-grandparents, “you can get some false labeling and oddball results,” he comments. The better companies have “gotten pretty good at knowing when that happens and when not to make the call” on various breed influences. And they’ll let you know when they send you the results.

So, what are you really learning when you get a window on the breeds that contributed to the DNA of your own dog? Often not much about behavior, especially if your dog is no longer a puppy and you’ve had her for a while. “Most people already know if their dog likes to herd, or nip them,” Dr. Bell says. You don’t need to analyze the dog’s DNA to figure out that she has a lot of genes coded for that behavior.

On the other hand, if a mixed-breed dog has just come into your life and it’s not clear what breeds she is descended from, learning her ancestry can prove very helpful in understanding her behavior and working with her DNA to train her rather than against it. Angela Hughes, DMV, PhD, the veterinary genetics research manager at Mars, knows this firsthand. “I picked up my dog on the streets of Portland, Oregon, as a stray,” she says. “I knew nothing about her. Turns out she is half Russell terrier, a quarter Australian cattle dog, and a quarter mixed [of unknown determination]. She is about the antithesis of what I would have wanted. My previous dog was a cocker spaniel and Maltese mix. Spaniels are bred to work alongside people. Terriers are not here to serve you and make you happy. So we’ve got a really high-energy, territorial terrier.”

How does it help Dr. Hughes to know that? “I’ve learned to work with her,” the veterinarian says. “We’ve learned to live with the blinds closed, because otherwise she will go completely ballistic to see a squirrel in the yard.” Knowing her dog’s breed also lets Dr. Hughes know that “she is not trying to make me angry.” It’s just who she is. In addition, she says that knowing the breeds that contributed to her dog’s makeup can make her think calmly, rationally: “How do I train around these innate behaviors” instead of “I’m taking this dog to a shelter.”

Along with learning information about breed characteristics that shape your dog’s behavior so you know she’s not simply being difficult, having her DNA tested may let you know about her potential for ending up with certain diseases.

Beyond breed identification

With the Mars test, called the Wisdom Panel and available for $84.99, one thing you’ll get is a prediction of your dog’s adult weight if she is still a puppy. That’s not a bad thing to learn since when you bring home a very young dog with uncertain genetic ancestry, you don’t know if she’ll be a small dog or a larger one. After all, a labradoodle can be more Lab or more poodle, with a potential for a wide swing in size and bulk from what you might expect.

Size expectations will also help you choose the right food if your dog is still a small puppy because you’ll find out if you’re supposed to be feeding her puppy food for regular size or large-breed dogs, who have different nutrition requirements.

But there’s more. The test looks for a gene mutation that predicts sensitivity to certain drugs and can also assess the chances that your dog will develop exercise-induced collapse. These are not by any means exceedingly rare issues.

Consider that a dog who tests positive for a mutation in a gene known as MDR1 (Multiple Drug Resistance 1) can potentially have problems with as many as 15 different medications. These include, for instance, acepromazine (a tranquilizer commonly administered before surgery because of its sedative and anti-vomiting effects); doramectin (which treats roundworms and lungworms, among other parasites); paclitaxel (a chemotherapy agent); and rifampin (an antibacterial drug).

MDR1 mutations create a higher-than-normal sensitivity to various drugs if a dog has it on one allele of a gene and a very high level of sensitivity if a dog inherits it from both parents. The mutation can make a dog react poorly to the anti-diarrheal drug loperamide, sold over-the-counter as Immodium. This is good information for owners to have because people sometimes use loperamide for their dogs when they have diarrhea and can avoid the drug if the mutation is present. (Collies, long-haired whippets, and Australian shepherds are most frequently affected by this gene mutation, but it also occurs in Shetland sheepdogs, other breeds, and, of course, mixed breeds.)

As for an increased risk for developing exercise-induced collapse, the test analyzes a dog’s DNA for a mutation in a gene known a DNM1. One copy of that gene mutation makes a dog a carrier who can pass it down to the next generation if bred; two genes, one from each parent, predispose a dog to actual collapsing episodes. Exercise-induced collapse affects nerve and muscle function, causing otherwise normal dogs to show signs of muscle weakness, loss of coordination, severe elevations in body temperature, and finally, life-threatening collapse when they participate in strenuous physical activity. It was first identified in Labrador retrievers, but that is not the only breed to pass along the faulty gene. The condition has been misdiagnosed as heat stroke, so it’s certainly not a bad thing to know if your dog has a propensity for it.

A second testing option

Let’s say you would like more information on your pet’s chances of developing various diseases than the basic genetic analysis shows. Such information could prove very useful. If, say, you learn your pet has a gene for joint disease, you’ll know that low-impact exercise is important to protect her joint cartilage. With people, of course, the doctor can just ask: Anyone in your family have arthritis? Heart disease? Dogs can’t communicate those particulars, but there are a number of ways you can get them.

One is to go through Mars, but the process can differ depending on whether your dog is a pure- or mixed breed. If your dog is purebred, for $100, you can send in a cheek swab, just as for the $85 breed-identifying test. Mars has partnered with a laboratory in Finland to offer another assay called the Optimal Selection Canine Genetic Breeding Analysis. It looks for gene mutations that predispose a purebred dog to more than 150 genetic diseases, everything from various eye problems to spinal diseases. Generally, this test is used by breeders in deciding whether a dog is fit to be bred or should not be mated — or should only be mated with certain dogs — because of the risk of passing on genetic mutations that can result in health problems. “It’s match.com as opposed to ancestry.com,” Dr. Hughes says.

If your dog is not a purebreed but you still want to learn her health risks for her own sake, Mars has a test that can be ordered through your veterinarian. Using a blood sample rather than a cheek cell sample (it’s slightly more reliable in terms of getting a good sample, Dr. Hughes says, and any veterinary clinic has the capability to draw a bit of blood), the test tells both what breeds a dog is descended from and whether gene mutations for more than 140 diseases are present. That way, you and your vet can partner to monitor your dog’s health throughout her lifespan, with an eye on those diseases that might, or will, develop based on your pet’s DNA analysis. The cost varies depending on the veterinarian you use, but it sometimes can be as low as the $80 range if your veterinarian practices in one of the Banfield hospitals, which are often located next to or in PetSmart stores.

Another good option is a company called Embark, which partners with researchers at Cornell University’s veterinary school to investigate heritable diseases of dogs. Embark offers a single test to identify both the breeds that comprise a dog’s genetic makeup and problematic DNA that creates risks for more than 160 diseases. The whole test costs $199; you can’t separate the breed identification assay from the health risk assay.

Why the slightly higher cost? A spokesperson for the company says that while “we owe a debt of gratitude to Mars” for starting commercial genetic testing on dogs, Embark tests for 100 times more genes than any other company and therefore can identify the breeds that make up a particular dog with greater specificity.

Whichever company you might choose — and both of those mentioned in this article will give you reliable results, pluses and minuses aside — this is a “new area of genetic testing: multiplex testing for hundreds of markers for different diseases,” says Tufts’s Dr. Bell. It’s especially important for dogs who are going to mate so they don’t pass down a problem, he says. But it’s also great for someone who wants to take the best care of her own dog in the here and now. “You essentially have universal genetic screening when your dog is young,” he says. “You know her susceptibilities, and then you can mitigate to help avoid problems during her lifetime. The whole idea of getting a genome panel when your dog is young is eventually going to give us individualized medicine in the way we currently conceive it should be.” 

Comments (0)

Be the first to comment on this post using the section below.

New to Your Dog? Register for Free!

Already Registered?
Log In