[Updated January 10, 2019]
The sequencing of the canine genome, accomplished as a public research project in 2004, opened the floodgates to endless possibilities for canine genetic testing. The holy grail for many scientists engaged in this work is the understanding of, and ultimately, the elimination of inherited canine diseases. For many dog owners, though, the most exciting outcome of this serious work is the possibility that they can learn exactly what breeds their mutts are made of.
Though there are already several commercial companies offering products that purport to be able to do just that, our assessment of the breed identification tests is that the results may be just as mixed as the dogs they seek to explain. The test results may be nearly as varied, interesting, and enjoyable as our mixed-breed friends, but it seems that, at least right now, they may not be able to absolutely satisfy the question of your mutt’s parentage. The tests are getting better every day, though! And as the understanding of DNA, the size of the sample databases, and the power of computers grow, it’s likely that the tests will, at some point, truly live up to the marketing hype currently being used to sell them.
Dog Breed Tests: A History
The first mixed-breed DNA test was born in the laboratory of Elaine A. Ostrander, Ph.D., and Leonid Krugylak, Ph.D., when they were with the Fred Hutchinson Cancer Research Center in Seattle. Drs. Ostrander and Krugylak were looking for genetic commonalities among purebred dogs recognized by the American Kennel Club (AKC). One goal was to discover the genes responsible for diseases common to both dogs and humans, including several types of cancer. They were also studying the relatedness of about 100 of the AKC-recognized breeds; this led to the discovery that the genetic variation between dog breeds is much greater than the variation within breeds. For comparison, genetic variation between human populations is about 5.4 percent; in dogs, they discovered, between-breed variation is estimated at 27.5 percent.
In 2005, Ostrander and Krugylak signed a commercialization agreement with Mars Veterinary™, a newly created division of the mighty Mars, Incorporated (yes, think candy, gum, pet food, and other foodstuffs), licensing the technology they developed for use in breed identification.
Mars Veterinary wasn’t alone in the race to market a breed identification product. Scientists at MMI Genomics Inc. (MMIG) were also studying canine DNA. In fact, MMIG provided identity and parentage verification services for the AKC, United Kennel Club (UKC), Professional Kennel Club (PKC), and a number of other canine registries and breed clubs. MMIG was originally a division of Celera, and led the private effort to sequence the canine genome. It was also the first to commercially market a breed identification test, in March 2007. MMIG called its product the Canine Heritage™ Breed Test. When it made its commercial debut, the test was potentially able to identify only 38 breeds; the test (“XL”) was upgraded in mid-2008 to identify more than 100 breeds.
Mars Veterinary brought its test to market just a few months later, in September 2007, as the Mars Veterinary Wisdom Panel™ MX test.
How Do Dog DNA Tests Work?
Each company promotes its tests by saying they are a good way for the mixed breed dog owner to learn whether his or her dog might be susceptible to a particular genetically linked disease if the dog has breeds known to inherit certain conditions. They also say that the tests help with training, by giving the owner insight into the dog’s behavior; the reason why the dog acts the way he does might be explained by his background. At the end of the day, however, company representatives admit that the majority of their customers buy the tests simply out of curiosity and because it’s fun to do.
The DNA tests we looked at draw their databases from the more than 160 breeds recognized by the AKC, and address only those breeds found in North America. Worldwide, it is estimated that there are more than 300 breeds of dogs.
The tests use genetic tools referred to as “markers” to define the concept of a dog breed. A genetic marker is a position in the genome where there is variability in the sequence that is inherited, following the rules of classical genetics. Two common kinds of markers are microsatellites and single nucleotide polymorphisms (SNPs).
Each company independently developed a set of markers that define the breeds in their databases and utilizes sophisticated computer algorithms to match a given mixed-breed dog’s DNA to that in its database to come up with the best breed match(es) for him. The analysis determines how closely, and to what extent, the mixed breed dog’s genetic patterns match those of purebreds.
There are two very significant players in the U.S. market (MMIG and Mars Veterinary) and a few that are trying to carve out a larger role. EDP BioTech Corp. is very new; a fourth company, DNA Diagnostics Center Veterinary, subcontracts its work to EDP BioTech Corp. There is at least one test (Viaguard DNAffirm™) offered by a Canadian company, Accu-Metrics Ltd., which we did not explore.
Mars Veterinary Wisdom Panel™
The Wisdom Panel MX was the only mixed-breed DNA test to require a blood sample. Initially available only through veterinarians, the test is now available online directly from Mars Veterinary, as well as from veterinarians and select pet supply retailers. It has a suggested retail of $125, which includes free shipping if ordered direct from Mars Veterinary. Nevertheless, a trip to your dog’s veterinarian is still necessitated for a blood draw, which means an extra cost for the vet office visit and procedure, and possible stress to your dog if he doesn’t love the vet office.
The AKC recognizes 161 breeds; the Mars Veterinary database includes 153 AKC breeds in its database, plus four breeds awaiting recognition from AKC, for a total of 157 breeds. To develop its database, Wisdom Panel typed more than 13,000 dogs during test development, completing more than 19 million genetic marker analyses. Mars Veterinary’s database is the largest of any of the three companies we examined, but its test is also the most expensive.
After extracting DNA from the blood sample, single SNPs – or slight variations in DNA makeup – are identified. The test exams 321 points or markers where variations are found, looking to form breed-specific patterns. A proprietary algorithm is then run on the data.
Angela Hughes, DVM, a veterinary geneticist and consultant for Mars Veterinary, explains it by saying the computer then “says” as it looks at the DNA of a particular dog, “If I have to make her one thing, what would be the best match? If two, what would she match, then three, then so on, up to eight. The result is then a statistical score to each ‘tree’ the program builds as to how that dog best matches.” Eight is the magic number as Mars Veterinary’s confidence level is to go back three generations (eight great-grandparents).
The company claims that the test determines breed composition with 90 percent accuracy, defining that as validation testing that has resulted in an average accuracy of 90 percent in first generation cross-bred dogs of known parentage (our emphasis).
As with the competing Canine Heritage test, the Wisdom Panel results are reported in three categories, only Mars Veterinary calls them Significant, Intermediate, and Minor breeds, roughly translating to parent, grandparent, and great-grandparent. For a breed to be listed as Significant, at least 50 percent of the dog’s DNA must have come from that breed (i.e., one of the parents was a purebred or possibly both grandparents were of the same breed); Intermediate, at least 25 percent; and Minor, at least 12.5 percent.
Mars Veterinary expects that if your dog shows a Significant breed, that he will likely display some physical and behavior traits from that breed, unless some of the genes are recessive. For Intermediate, you “may” see some physical and behavior traits of that breed in your dog, and for Minor, it is unlikely that the breed’s physical traits are visually represented in the dog unless some of the genes are dominant.
The company quotes a two to three-week turnaround on test results; test status can be tracked online – and results, when ready, will be mailed to the client but are available online sooner. The only contact information for the company that is offered on the website is an e-mail address; as unhelpful as that is, the website itself offers tons of information.
When we did find a phone number to reach the company, the representative who answered was moderately helpful, although he was more prepared to deal with someone calling to discuss their dog’s test results than with someone looking for in-depth information about the company and its products.
See Wisdom Panel’s products here.
BioPet Vet Lab / PooPrints
The latest entrant into the market is the DNA Breed ID Test offered by BioPet Vet Lab, a division of EDP Biotech Corp. BioPet Vet Lab itself was created in late 2007; its canine DNA test was launched in early 2008 through online resellers. In addition to the breed ID test, BioPet also offers DNA proof-of-parentage testing, DNA pet ID, and the very interesting PooPrints™ program (“match the mess through DNA”).
The company’s goal is to offer a sound, affordable test. It hopes to accomplish this by limiting the number of breeds in its database to 63 – which the company claims represents “about 93 percent of the dog DNA that is in the U.S. according to historical trends in breed popularity” – and pricing the test at $60. Adding additional breeds requires adding more markers, which increases cost; BioPet suggests that it will most likely top out its database at 65 to 70 breeds. This test, too, uses a cheek swab to collect a dog’s DNA.
The company sells its tests through PetSmart, Pet Supermarket, other retailers, and online retailers. Turnaround for results is roughly two weeks, and it does not appear that the company has online tracking capability for test status. They will re-run a test upon request, acknowledging the possibility of human error, but company spokesperson Meg Retinger reported that even in the ones they’ve rerun, they have never seen a test result that was completely different on the second run. The BioPet website has a moderate amount of information, and the company spokesperson was helpful.
Happy Consumers of Mixed-Breed Dog DNA Tests
Ruby, named for her short red coat, was brought home to Rosalie and Leonard Sanchez of Riverside, California, by their 15-year-old grandson, who got her from a lady giving pups away from the back of a pickup truck. The lady told their grandson that the puppy was a St. Bernard mix. Rosalie quickly dismissed his words, figuring that he made up that piece of the story, because Ruby looked nothing like a St. Bernard.
Early this year, she learned about the Canine Heritage test, and was curious to know more about Ruby’s background. She and her husband guessed Ruby was part Boxer. Their veterinarian concurred, because of Ruby’s large paws; his guess was Boxer/Great Dane or Boxer/Mastiff.
When the results came back, Rosalie was floored; her grandson was correct after all! The test showed Boxer and St. Bernard. Although she still can’t get over how Ruby does not resemble a St. Bernard, Rosalie says, “A mixed breed dog is like a box of chocolates. You never know what’s on the inside.”
Dan McCarthy’s girlfriend found Flora lying next to a bus stop, emaciated and covered in fleas. Their veterinarian thought Flora was a Labrador and Springer Spaniel mix, yet she was on the small size, weighing 30 pounds at age two. Other people guessed Border Collie and Jack Russell Terrier.
Dan, a resident of Hollywood, California, wanted to know as much about Flora as he could. “I want to know who her mother and father were, where they are now, and show them Flora has grown up to be a great dog with a great life,” he says. Last summer he ordered the Canine Heritage test. The results showed that Flora’s parents were probably not purebreds — nothing listed in Primary category, just as Dan had suspected. The Secondary level, though, reported German Shepherd and Cocker Spaniel. Dan was amazed. “The Spaniel explains why she is so small, and the Shepherd explains why she is so smart!”
Kitty Cannon of Crystal Beach, Florida, and her husband had always played a guessing game about their dog’s breed makeup. When they learned about DNA testing in 2008, Kitty thought, “Why not? Since we can’t afford to have Fox cloned, maybe by knowing his breeds we can in the future look for another great dog with his traits.” They guessed Fox was part Collie or Sheltie. When their Canine Heritage results came back, they were surprised to get Bernese Mountain Dog in the Secondary category, and Chow Chow “In the Mix.” Only a higher being would know for sure whether the results are accurate, says Kitty, “but we do notice some similarities as to where he got his fur color, ear shape, and jowl line. We know they broke the mold with him and there will never be another.”
Evelyn Orenbuch, a veterinarian from Philadelphia, ordered the Mars Veterinary Wisdom Panel MX for her rescue dog, Pia. “I wanted to know if Pia’s behavior had anything to do with the breeds I thought she had in her. We guessed Border Collie, Whippet, and…?” The results matched at only the lowest levels, revealing German Shepherd and a couple of other breeds. Dr. Orenbuch was somewhat disappointed, as she had hoped to have more information about Pia’s origin. Nonetheless, she says she would recommend the test to clients. “Knowing what breeds are in your dog helps you to understand his emotional and physical aspects. It may not change what you do with your dog or how you treat him, but it may help you to understand him.”
Breed Testing Criticism and Limitations
The Wisdom Panel (Mars Veterinary product) has been criticized because it requires a trip to a veterinarian and a blood draw. This increases the cost of testing, and could stress vet-averse dogs. Critics also suggest that blood samples can be damaged in transit to the lab.
Mars Veterinary defends its decision to use blood by explaining that DNA from a blood sample is the “gold standard” as the quality and quantity of DNA derived is better than from a buccal (cheek) swab. Mars Veterinary’s Dr. Hughes says that the DNA in blood is actually very hardy, and, in fact, the lab has to raise the temperature of the DNA to near boiling repeatedly during the SNP analyses. The company also uses specially designed plastic tubes to protect the blood tube in transit.
Cheek swab tests receive their own criticism. Buccal swabs have a higher failure rate due to variation in owner sampling, such as not collecting enough cells. Also, because of bacteria in dogs’ mouths, there is a potential for bacterial growth if the samples aren’t handled correctly.
Then there are criticisms from consumers. One recurrent theme of unhappy clients is that results of a DNA test failed to find a preponderance of any particular breed in their “very mixed mixed-breed” dogs. (See sections below.)
Another has to do with the fact that some dogs don’t look anything like the breeds that their tests detected. It’s difficult to feel good about a result that doesn’t confirm or explain anything about the dog’s physical appearance or behavior – and the companies’ explanations for this phenomenon may be unsatisfying.
The Wisdom Panel website says, “Many parts of the canine genome are likely to be unobservable or hidden with regard to trait determination. This can happen for any number of trait-determining genes. Simply put, a mixed-breed dog could be a mix of three or four breeds but have few traits evident from one or more of these breeds.”
MMIG’s explains: “Canine Heritage Breed Test only works for the breeds that have been validated. If your pet’s breed composition contains non-validated breed(s) the test may identify breed(s) earlier in your dog’s ancestry. This may cause identification of apparent unlikely breeds for your pet’s composition.” How valid are the results?
To get some perspective from an independent expert on canine DNA, we interviewed Beth Wictum, director of the Veterinary Genetics Laboratory at the University of California-Davis School of Veterinary Medicine. Wictum has been with the university for 30 years. She has participated in and witnessed the evolution of the science that makes it possible to identify an animal through the study of its tissue; during her tenure, “state of the art” has gone from blood typing to sequencing the genome.
Asked to comment on mixed-breed ID tests, Wictum emphasized that the tests are only as good as each company’s database; that is, if a breed is not represented in a company’s database, then the test will identify the next closest match. She explains by saying that purebred dogs, especially registered purebreds, have been intensively managed and have a limited genetic pool.
“Most breeds have been created through intense selection over the last few hundred years, so there has not been enough time for them to diverge through mutations,” she says. The differences between breeds lie in the selective breeding by breeders for morphology (structure) or behavior. Therefore, the ideal breed test would be one that looks at those traits that characterize each breed and makes them unique.
“The field of canine genetics is still young; the dog genome was only sequenced about five years ago,” she says. “We are just starting to identify the genes responsible for various traits.”
Like many scientists in this field, Wictum is excited about the potential for identifying the genetic basis for various diseases. She says the Veterinary Genetics Laboratory at UC Davis and the Bannasch Laboratory (also at UC Davis) “are identifying the genetic basis of various diseases, which can then be offered as tests to the public. If you know what diseases may occur, you will be able to have your pet tested to see if he carries the mutation.”
Her advice concerning the mixed-breed DNA tests? “While these tests may indicate breeds that contributed to your pet’s genetic makeup, you must realize that they aren’t 100 percent accurate – and I don’t think they claim to be. If you have the money to spend and want to do it just for fun, then absolutely go ahead and do it.”
Some Owners Say Breed Testing is Not Worth It
Laura Pescador of Denver, Colorado, ordered the Canine Heritage test for Misha, her “60-pound, black and tan, square-nosed, short-haired, big-eared, deep-chested, bi-eyed mystery mix” in May 2008. Laura felt the breed combination she was told when she adopted Misha was unlikely (Australian Shepherd/Labrador Retriever); she was also hoping to receive a piece of paper that said that Misha was not a pit bull-mix, “Not because I don’t like them but because of my city’s breed-specific legislation.” Laura was disappointed to receive an “apology letter” with results stating that the test was inconclusive! On her certificate, next to “Primary” was written “Untested Breed,” while the other two categories were blank.
Scamper, Monty, and Rainey are three mixed breed dogs belonging to veterinarian J.C. Burcham, of Olathe, Kansas. In early 2008, she submitted blood samples for each dog to the Wisdom Panel test. Dr. Burcham was pretty sure that Monty was “several generations of mutts breeding to mutts” and had few expectations for his results. She calls Scamper a Jack Russell/Basenji/Beagle mix, so was expecting to see something like that, or even some terrier breed. Rainey was found as a puppy in rural Virginia, starving to death with two littermates, all three of whom looked like Border Collies.
When the results came in, Dr. Burcham was disappointed. “I felt like it was a complete waste of money! Rainey is clearly part Border Collie, and that was about the only reliable result I saw. Two of my three dogs were found to be “too complex” to identify. I could have told you that! That’s why I paid for the test.” Rainey’s results showed “some” Border Collie; however, she showed distant traces of Briard, Cairn Terrier, Great Dane, and Keeshond. Monty’s test revealed distant traces of Alaskan Malamute, Beagle, Bearded Collie, Chow Chow, and Smooth Fox Terrier, while Scamper’s showed trace amounts of Briard, Curly-Coated Retriever, and Shetland Sheepdog.
Dr. Burcham’s primary disappointment was seeing Briard in two of her dogs, which was unlikely, in her opinion. She was also annoyed that Scamper and Monty were dubbed “extremely complex mixed breed dogs.” With just 10-15 percent of mixed breed dogs falling into that category (according to Mars Veterinary), how could she have two of them?
I shared Dr. Burcham’s disappointment with Dr. Hughes, the Mars Veterinary consultant, and she offered to not just look at, but also to rerun the three tests. In the year since Dr.
Burcham submitted the samples, 23 additional breeds have been added to the Mars Veterinary database, and its algorithms have been modified. The company had found that the program was breaking down dogs into a lot of small pieces, “losing the forest through the trees,” resulting in some false positives. Results now are typically a smaller number of breeds and potentially in larger “amounts.”
When Rainey’s test was run again, Briard and Cairn Terrier did not appear; they had most likely been false positives. Border Collie bumped up to the Significant (parent) level, and Great Dane and Keeshound showed up at the Intermediate (grandparent) level. Monty’s results showed Beagle and Chow moving to the Intermediate (grandparent) level; the other breeds still were evident but could not be called with confidence, so they were likely false positives in the first test.
Scamper’s new results still revealed a “very mixed dog.” Curly-Coated Retriever moved to the Intermediate (grandparent) level, and Golden Retriever showed up at the Minor level. Briard and Sheltie were potentially part of her distant history or false positives. Also detected were Anatolian Shepherd and Australian Cattle Dog, which Dr. Hughes felt were more likely than Briard and Sheltie.
Nancy Kerns Weighs In
Of course when author Lisa Rodier proposed the idea of writing an article about the mixed-breed identification tests, [ wanted to have my mixed-breed dog, Otto, tested – you know, just for journalism’s sake! But which test should we order, from which company? We quickly decided to order the most extensive product from each of the two industry leading companies and compare the results.
Otto had a vet appointment coming up, which I used as an opportunity to have his blood drawn for the Mars Veterinary Wisdom Panel. We followed the normal protocol: I paid the vet for the blood draw and the test; his staff sent the sample to the lab, and gave me a test ID number so I could check on the progress of the test using the Wisdom Panel website.
The following day, I brought Otto with me to PETCO to buy a test kit for MMIG’s Canine Heritage “XL” test (this company has since been bought by Wisdom Panel). PETCO’s grooming department staffhave been trained by MMIG to collect cheek swabs. Following the trip to the vet the previous day, Otto was nervous, so I collected the cheek swab myself (but asked a PETCO staff member to pose with the sample and its mailing envelope, you know, for science).
DNA Test Suspense
Waiting for results was excruciating 7 especially since Canine Heritage sent me an e-mail the day after I mailed the cheek swab, confirming its receipt in its Davis, California laboratory (I live about 70 miles from Davis). This gave me the idea that I might receive results soon – but it took a full seven weeks to receive them in the mail! (MMIG says results should arrive in six to eight weeks; it was just the anticipation that made this wait seem interminable. Plus the fact that you can’t get the results online.) I checked the website for the Wisdom Panel results every day. Just three weeks after Otto had his blood drawn, I saw that the results were complete, and I could download the Adobe Acrobat file that contained them.
So? What is Breed is Otto?
The Wisdom Panel results said, “The analysis revealed that Otto is a fairly mixed dog and we have not found evidence of a purebred parent or grandparent.” (I think I knew that!) There were no results at the “Significant” or “Intermediate” level. However, at the “Minor” level, these four breeds appeared: German Shepherd Dog, *Basenji, *Chow Chow, and *Border Collie. The asterisks indicated “Minor amount detected at low confidence. These results are not included in accuracy calculations.” (Me: “Basenji?!”)
The Canine Heritage results showed nothing in the “Primary” category, Chow Chow in the “Secondary” category, and Poodle and Border Collie “In the Mix.” (Me: “POODLE?!”)
My Expectations
I would have guessed that Otto had some German Shepherd Dog in him, and I was even expecting some Chow Chow. He definitely has a GSD-sort of tail and his ears are very Chow. When he’s soaking wet and his hair is slicked down, his body shape looks a little like a Golden Retriever. And I was certain there had to be some terrier breed in him. How else do you explain that fuzz-face?
The shelter that I adopted him from guessed he was Airedale and Border Terrier. (I give them a break; he was only about five months and little when they got him.) Though this breed does not appear in either the Canine Heritage or Wisdom Panel database, author Lisa Rodier was rooting for a Picardy Shepherd (Berger Picard) result; she thinks he’s a ringer for the Winn-Dixie dog. Nobody guessed Border Collie, Poodle, or Basenji.
Why Didn’t the DNA Tests Work?
How can the two companies have such different results for Otto?
We asked Theresa Brady, spokeswoman for MMIG, to address this question. She replied, “Each company developed its test independently, so there are a number of factors that can result in different breeds recognized in a particular dog. During the research phase, each company must identify a set of DNA markers that characterize differences from breed to breed. Then these markers must be characterized in a set of dogs representing the pure breeds.
“Not only are these markers different across companies, but the number and source of the purebred dogs are different. No company can test every purebred dog representing a breed, and every company will have developed software that is used to compare these genetic markers across breeds.
“Some breeds, however, are closely related because they were developed from the crossing of older, more established breeds. For example, Boston Terriers were developed from the crossing of the English Bulldog and English White Terrier. So, depending on the software program, the markers established for the purebreds and the population of breeds in each company’s database, the same dog may test ‘Boston Terrier’ with one company and ‘English Bulldog’ with another.
“Some breeds are related because they arose from a common lineage, such as many of those breeds developed from Asia. Early on, we (MMIG) recognized that the Chow Chow, the Akita, the Siberian Husky, the Chinese Shar-Pei, and even the Shih-Tzu can cluster together as one general breed type so we developed an enhanced program and analysis procedure to split these apart. Thus it is not surprising that the companies may report slightly different results, especially for the breeds that have just a small representation in the mixed breed pet.”
Addressing any results that appear in the “Secondary” section of a report (where they detected Chow Chow in Otto), the MMIG (Canine Heritage) results packet says, “This category reports breeds that might be easily recognizable within your dog. While these breeds may or may not have a strong influence on your pet, each breed listed makes up less than the majority of your dog’s DNA.”
Addressing results that appear in the “In the Mix” section of a report (where they detected Poodle and Border Collie in Otto), the Canine Heritage packet says, “This final category identifies breeds that have the least amount of influence on your pet’s composition. They still appear, at low and measurable amounts, in your pet’s DNA. If your pet’s results only identify breeds in this category, it is possible your pet is composed of so many breeds only small influences from each breed can be detected.”
The Mars Veterinary (Wisdom Panel) results packet explains, “Because of the complexity of genetics and the passing on of dominant and recessive genes from generation to generation, every trait from the breeds we found may not always be visually apparent. It is important to spend time closely observing Otto’s appearance and personality. Think about which of Otto’s traits may reflect a combination of the breeds detected, and which seem to reflect just one of the individual breeds.”
Our Opinion on Breed Testing
I have to say that I found the whole exercise very interesting, but not necessarily worth the cost. Given that the results for my very mixed-breed dog were so weak, the idea that they might help me anticipate certain health or behavior problems linked to the breeds found is not very compelling. But I doubt that’s why most people order the tests; I think most of us are just curious.
Having spent so much time examining and admiring the technological achievements that went into the development of these DNA tests, Lisa Rodier was afraid I would pooh-pooh the science behind these tests because I was so skeptical of the breeds detected in Otto’s lineage. It’s not that; I trust the science. I believe there are traces of these breeds (and many others) in Otto. It’s just that I already knew he was a very mixed dog, just from a (free!) look at him. And if he wasn’t such a mixed bag – if he looked a lot like one particular breed, I’d probably be satisfied with the idea that he was mostly that breed; I wouldn’t spend $100-plus to confirm it.
That said, I must admit I will be interested to see how the results might change in a few years, after these companies put thousands and thousands more dogs into their databases. Which breeds will “fall off” of Otto’s results as meaningless “background noise”? Will the Picardy Shepherd be added? It could still develop that Otto is a limp-eared Picardy who fell out of a French tourist’s car somewhere in the Northern California wine country…We’ll check back with these companies in a few years, and let you know.
– Nancy Kerns
Dog DNA Testing FAQs
Canine mixed breed tests seem to be a very emotional topic. Those who have used the tests and have gotten the results they expected tend to be proponents, while those who received weak results or results that didn’t seem to square with the dog’s appearance tend to regret the purchase. But does that mean the tests don’t work? Here’s a stab at trying to explain some of what might be going on.
Breed results are reported in levels; Why is my dog only getting “minor” or “trace” breeds and no strong hits?
Dr. Hughes explained that most likely the dog’s parents and grandparents were themselves mixed breed, and a portion of the dog’s ancestry can be mixed beyond three generations which, for Mars Veterinary, is the extent of the company’s confidence. There is also the possibility that a breed is not covered in the database (for example, none of the tests’ databases include Rat Terrier) so the test will look for the most closely related breed.
My dog looks like X, but the test says she’s Y…
Dr. Hughes explains that we want to associate a particular trait with one breed, but in actuality, it could be coming from a number of breeds. And when we move across breeds, combinations of genes can create very unusual outcomes.
One way she looks at the issue is first looking at a dog’s traits, defining what genes are necessary to get those traits, and then asking whether we can get those genes in a particular breed? For example, the merle color pattern, very common in Australian Shepherds, comes from a single gene, and a dog need only have one copy of that gene to exhibit that color pattern, And guess what? Dachshunds, Chihuahuas, and Great Danes can all provide that gene.
Black and tan coats are commonly associated with Rottweilers and Dobermans. But Chihuahuas, Cocker Spaniels, Dachshunds, and Poodles all carry this gene mutation. But in this case, it is recessive, so two copies must come together for
us to actually see that color pattern.
Meg Retinger of BioPet also points out that in some very mixed dogs, you might only see very subtle traits, such as the shape of the ear or the eyes. Her son’s dog tested as showing Beagle, yet she looks very much like a Labrador. When she howls, however, she sounds like pure Beagle!
My dog is a Labradoodle (Labrador Retriever-Poodle cross), so why doesn’t the test say she’s a 50/50 mix?
We let Theresa Brady of MMIG address this, as she herself owns a Labradoodle. When she tested her dog using the Canine Heritage test, the results showed that Poodle was a Secondary breed, with Labrador Retriever “In the Mix.”
She explains, “You should know that my dog came from a breeder who claimed that the dog was seventh generation Labradoodle, which means that neither of her parents was a purebred (purebred Poodle or Retriever) and neither of their parents were purebred and so on. It makes sense, then, that she had nothing show up in Primary.” When I asked why the Poodle was Secondary, but not the Retriever, her guess was that the breeder probably crossed back more Poodle, looking for a more hypoallergenic coat. Dr. Hughes adds, “When breeding Labradoodle to Labradoodle, the “amount’ of Lab or Poodle genes passed down is random chance (think of a Pachinko machine). Testing the dog’s littermates may show very different proportions of each of these breeds. That being said, some ‘Labradoodle’ breeders are back-crossing Labradoodles to Poodles to change the size or coat of the dogs. I have seen some really strange looking Labradoodles!”
How can dog DNA tests get better?
Increasing the size of the database, increasing the number of markers, and overall innovations in technology will see the tests become better tools. Also, as research continues on canine genetics, a better understanding of genes and how they relate to various breed traits will play a role in making a better test.
Lisa Rodier lives in Alpharetta, Georgia, with her husband and two Bouviers.
