Cracking the Genetic Code

More than half of all dogs in the United States are mixed breeds. From designer dogs to mystery dogs, chances are your practice sees a lot of lovable mixes. Does it really matter whether those floppy ears came from a Lab or a Spaniel?

It turns out that it may matter very much. A dog’s genes carry information that a physical examination can’t reveal. A DNA test is the only way for pet owners to find out exactly which type of canine ancestry their dogs can claim.

DNA testing has come a long way in recent years. One of the leading tests, Mars Veterinary’s Wisdom Panel^™ MX DNA test, draws on research done across the canine genome by the United Kingdom-based Waltham Centre for Pet Nutrition. Working with 19 million DNA markers in samples collected from 13,000 dogs in the United States and United Kingdom, Waltham’s researchers identified 300 genetic markers that help to determine which breeds are in a dog’s background. Results are 90 percent accurate, according to Mars Veterinary.

Examining a small blood sample from the dog, the computer program analyzes each chromosome from the sample against Mars Veterinary’s database of more than 9,000 purebred dogs to find out which one is the best match. Dr. Neale Fretwell, chief companion animal geneticist for Mars Veterinary, says that the test covers 99 percent of American Kennel Club breeds, as well as four foundation breeds (breeds that are in the preliminary stages of being recognized).

“Each dog is a puzzle,” says Fretwell, and, of course, no two dogs have identical DNA. “But what the test results tell the veterinarian—and the dog’s owners—is how much of Fluffy’s make-up comes from different breeds.” And that knowledge is power in creating a health and wellness program tailored precisely to the individual dog.

 

WHY IT'S BEST TO TEST

Despite certain breeds’ tendency to display specific physical traits, not all mixed-breed dogs wear their ancestry on their faces. That dog you thought was a Terrier mix could be a Retriever. Or it could turn out not to be a mix at all.

Mars Veterinary invited The Team to test a dog using the Wisdom Panel, and we chose Milo, a 12-year-old, 74-pound dog adopted from a Chicago shelter eight years ago. With his long muzzle and golden coat, Milo looks like he could be a mix of Golden Retriever and Collie. The shelter identified him as a Collie mix, and Milo’s veterinarian guessed he was a Retriever mix. The Wisdom Panel results showed neither breed present in Milo.

While Fretwell is still researching Milo’s lineage, he believes the dog is a purebred, possibly a Hovawart, a German breed that is rare in the United States. Milo’s DNA markers revealed a low degree of variation, typical of purebreds.

 

THE COST OF HEALTH

Breeds’ medical needs vary widely, so knowing a dog’s background can help you work with its owner to personalize its care. You can inform the owner about which physical or behavioral changes could signify a life threat to a particular breed or breed mix, as well as how to provide the right food and the proper amount and type of exercise.

You can also help owners understand not only what tests their dogs need, but also how to focus on the most important tests, says Michael Rumore, DVM, of Lake Seminole Animal Hospital, Seminole, Fla. For example, a Boxer is more prone to arrhythmias than other breeds, so an EKG becomes more important.

“Knowing a dog’s breed doesn’t magically fix anything, but it does allow veterinarians to understand aliments to which the dog is predisposed,” says Carol Osborne, DVM, founder and president of the American Pet Institute. “Using this targeted information, and understanding that longevity is attributed 30 percent to genetics and 70 percent to lifestyle, the veterinarian and owner can work together to create a wellness plan to help reverse, retard and/or prevent expression of those unwanted predispositions.”

The insights gleaned from a DNA test can help owners better care for their pets in the short and long term as well as in emergency situations. Osborne explains to owners of dogs she thinks may carry sighthound genes that DNA testing could save their pets’ lives. “These dogs are extremely sensitive to anesthesia. Owners may find that information to be lifesaving in case the dog requires surgery,” she says.

Since most dog owners are naturally curious about their dogs’ heritage, sparking owners’ interest in the DNA test can often be simply a matter of informing them about its availability. Consider spreading the word by offering to give DNA tests to dogs in a local shelter. Or add a financial incentive, such as a free office visit or fecal test for a client who has a dog tested.

Spreading tests over the year can lessen strain on both dogs and their owners’ wallets. Rumore advises splitting up routine wellness care and doing the DNA test with one of those appointments. “If the owner doesn’t want to have the test done right then and there, suggest he or she do it next time,” he says. “That makes the cost more manageable for the owner. Just be sure to add reminders so the client doesn’t forget or lose track of time.”

For about the cost of a few months’ worth of doggie treats and toys, a pet owner can provide a veterinary practice with information that can keep a dog healthier longer.

“With all of the canine genome information available, we have new opportunities to create regimens tailored to the individual pet,” says Rumore. “The goal is not only to maximize the quality and length of the dog’s life, but also to bring the pet and owner closer.”

 

WHAT HAPPENS IN THE LAB

How are breed matches determined in the lab? The first step is isolating the DNA, a process of chemical steps performed by a robot, explains Dr. Neale Fretwell, chief companion animal geneticist for Mars Veterinary. Then a computer program identifies more than 300 genetic markers called SNPs (pronounced as “snips”) in 13 different reactions. The variant patterns found in all the markers are fed into a program that tests them against the 157 pure breeds in the Mars database.

The computer program allows multiple combinations of breeds to be tested as a match for a dog, and the process is repeated more than 7 million times until the computer determines the best statistical match.

 

GETTING EVERYONE INVOLVED

DNA testing can help a veterinarian and client work together more closely. The rest of the team is vital for spreading information about the test. Here are some things your team can do to help clients understand the test and its benefits:

Veterinarians: Make a discussion of the test part of your team’s vocabulary when talking to clients. Explain how knowing a dog’s heritage can help you create a wellness program as unique as the individual pet. Test staff’s mixed-breed dogs to demonstrate what can be learned about a pet’s ancestry.

Technicians: The Mars DNA test requires a small blood draw completed by a veterinary practice. Be ready to explain the process to clients, and how the blood should be handled for shipping and mailing. Bone up on ailments common to certain breeds of dogs.

Receptionists: Know how DNA testing works, and familiarize yourself with the benefits of including testing in wellness programs. Suggest DNA testing in reminders to clients.

Practice Managers: Explore the idea of using financial incentives to encourage use of the DNA test, such as a free fecal test for everyone who
has a dog tested. Display posters showing common ailments among various breeds.

 

FOR MORE INFORMATION

To find out more about dog breeds and DNA testing, visit:
Wisdom Panel^TM MX: www.wisdompanel.com
Waltham Centre for Pet Nutrition: www.waltham.com

 

Mary Scoviak is a Cincinnati, Ohio-based editor and writer.

 

Presented in the Fall 2009/Vol.6.No.4 Page 6-8 of the Team magazine. The Team is published to complement Pet Quarterly an educational resource for veterinary clients. Both publications are part of the Veterinary Marketing and Staff Development Program of Purchasing Services Inc.