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Can DNA Decipher the Mix?

Germane to this tale is that, according to the unwritten rules governing canine physiology, anatomy and behavior go hand in hand. One cannot be changed without affecting the other. Victorian enthusiasts who were busily adding aesthetic traits to utilitarian breeds were creating not only subtle variations in type, but in many cases, modifications in behavior as well. As utilitarian breeds went from working hard to hardly working, many exhibited new physical and behavioral characteristics that were compatible with their augmented duties as companion animals. Breeders claimed the “sub-breeds” as their own, made up new names and registered each one.

However, no matter how they’re sliced and diced, reducing and suppressing genes so they aren’t expressed doesn’t mean they’ve been eliminated. They’re still lurking and, depending on the method used to analyze the DNA, the lurkers often show up in the results.

Deconstructing Breeds
The problematic aspect of analyzing mongrel DNA is that breeds were not all created at the same time. As DeNise explains, “As new breeds are developed, they may not appear as uniform as older breeds. When older breeds are crossed to create a new breed, there is some period of time before the new breed develops a unique DNA pattern of its own. In these cases, the more ancient breed sometimes appears in the new breed. The number of generations required to have a uniquely identified breed created from crossing of older breeds depends on the number of breeding animals in the new line, the severity with which the breed owners apply the standard, and the amount of introgressing [inbreeding, or breeding immediate relatives; line breeding, breeding close relatives; and backcrossing, breeding sibling to parent] allowed by the registration agency.”

Most people assume all mixed-breed dogs had a purebred ancestor at some time in their recent heritage. But in fact, this is not necessarily the case. When you run a mongrel’s DNA through a computer program, the algorithms attempt to group breeds together on a scatter chart. If the heritage of the dog is such that it is not in MMI’s database of 108 breeds, the program tries to find varieties that are most alike. Because at least one or two of the handful of ancient breeds are in every modern dog, sometimes the program will identify an ancient breed in the mix. “In the report we send to the client, we use the terms ‘primary,’ meaning the majority of the DNA matches a breed; ‘secondary,’ meaning less than the majority of the DNA but a strong influence nonetheless; and ‘in the mix,’ meaning the least amount of influence,” DeNise notes. That’s how you might get an obscure breed in the report. For instance, a 35-pound mongrel with a tablespoon of Husky and a teaspoon of Border Collie may also have a dash of Borzoi, because before gene pools were closed a century ago, Huskies were crossed with coursing hounds to add speed.

Don’t Judge a Pup by Her Cover
As MMI Genomics states on their certificates, “Your dog’s visual appearance may vary from the listed breed(s) due to the inherent randomness of phenotypic expression in every individual.” What this means is that you may look nothing like your parents, but you have Grandma’s great legs and Great Uncle Harry’s turned-up nose. All in all, though, no matter how genes are mixed and matched, your family members resemble one another. However, if Grandma was an Afghan Hound and Great Uncle Harry was a Pug, “random phenotypic expression” can be pretty extreme.

Researchers are intrigued by data that suggest expressed traits are somehow turned “on” and “off” by other genetic components, thus causing the wide variations in canine form and behavior. For instance, it’s possible that many breeds have the genetic potential for a black tongue, but only a few breeds have the molecular mechanism to switch that color on. So that black-tongued mutt may not have any Chow in the mix after all.

On the other hand, the results may show that a quintessential Heinz 57 has the genetic makeup of a single breed and it could be one she looks nothing like.

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Submitted by Anonymous | August 4 2011 |

Fascinating. So are DNA tests accurate enough to be useful in identifying the breeds in your mutt?

Submitted by Dave Strack | February 5 2013 |

I am still a skeptic as to the accuracy of these tests. There have been results that have been documented in which the same dog's sample was submitted to the same lab twice with entirely different results, dogs with color patterns and coat types that have been studied to identify the specific genes needed to produce them but the DNA test did not identify any breeds in the test result that could have produced the dog being tested, and an unscientific report of a test on ans 8 pound dog that listed only large breeds in its ancestry (a little white Rottweiler?).
The DNA testing is not one where a sample is put into a machine that spits out the answers. A human still has to interpret the raw result to come up with the answers - can you say human error. If you are just curious go ahead and have your dog tested. I would not like to think of a situation where my dog's life depended on these test results.

Submitted by Jane Brackman | March 28 2014 |

Read a more recent article I wrote about DNA tests, published in Bark in December 2012. http://thebark.com/content/do-dna-tests-reveal-genetic-secrets
You still may be a skeptic, but you'll have more knowledge about why the tests are accurate but appear contrary to what we see in our mixes.

Submitted by Lorri | October 20 2011 |

Thank you Jane Brackman for this article. It was very informative and interesting. I'd love to know what has transpired, since it's been three years since the article was published in The Bark.

Submitted by Jane | March 1 2012 |

That's the same thing I've been asking myself Lorri. And yes, I'm working on an updated piece. I've been sending my mixed breed pooches DNA into two companies to see if the results are the same.

Submitted by Kathi | July 30 2012 |

Jane,

I have been doing my own research on the various DNA tests plus DNA breed identification. This is because my city has a breed ban on certain breeds of dogs. I am not a scientist:( which makes this difficult. Mars Wisdom Panel is the only test that is available now to my knowledge. The shelter at our city has been testing questionable mixed breeds since 2009 with the Wisdom Panel Professional. We've done 20+ dogs so far. We have even done both test(Insight & Professional)on the same dog to see if we received the same results (we did). Our city does not acknowledge DNA testing but the city council is open on us gathering information (with the city) to determine if DNA testing can determine the banned breeds. Our city will accept the banned breeds if they are less than 50% of the banned breeds. This is currently determined by animal control officers visual identification. When will your updated piece be out? I'll be looking forward to it.

Submitted by Mia | November 17 2012 |

It is completely cruel and just plain wrong to ban an entire breed of dog. The dog is what you bring it up to be. PEOPLE are the ones that should be punished for TEACHING the dog to fight or be cruel or purposely inbreeding....Jail time and permanently keeping animal cruelty on their records should be put into law!

I have recently gotten a pitt bull mix (weimeraner we think) but he has fit right in! And is the most loving dog....I have six dogs and the lab/labradoodles that we have are more aggressive than he is - Especially with strangers walking in front of the house or people coming in....

Banned breeds should be banned people - people are the ones that are cruel.

Submitted by Anonymous | February 4 2013 |

I agreed to watch a friend's pitbull for one night and he moved out of state. So I had this huge brendle 11 year old pit bull, and I was scared of him. I had him for 3 years, and he was one of the most sweetest dogs I ever owned. At first I thought he was mute, he never barked for 3 months until I had him tied up outside and I walked out of his line of sight, that was the first time I ever heard him bark. A drunk friend of mine climbed through my window in the middle of the night and the dog just tackled him and licked him to death. I thought "what a lousy guard dog." But I would take him with me on runs, and a creepy guy approached me and he sensed my unease and went after the guy. He would let babies ride him like a horse. He was a great dog. But I couldn't get renter's insurance because of him.

Submitted by Anonymous | October 27 2011 |

So the "groups" are: Two hounds, MULTIPLE Spitz dogs, and a few small breeds... I think these groupings are messed up. At the very least, Asian Spitz dogs should have been one group (with the exception of the Chow Chow the visual and behavioral similarities are striking.)

Submitted by Erin | April 18 2012 |

Thanks for the interesting article! I had my dog's DNA tested recently and it was an interesting experience to say the least! She came back with about nine different breeds detected! The Humane Society believed her to be an Australian Cattle Dog/mix, however none was detected. They came up with boxer/miniature schnauzer mixed with a keeshond/chow chow. We really just did it for fun and it was affordable (around $60), but it might be interesting to see if the other companies that offer this service would come up with similar results. I am looking forward to reading your follow-up article regarding this. Of course, we love her no matter what the results are!

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