A dog’s breed can tell you a lot about his appearance, personality, and even his odds of future diseases. The ancestries of some purebreds are better documented than those of most people, allowing owners to investigate their dog’s family tree. If your dog is purebred, you may be able to discover that he has Best In Show heritage several generations back just by looking at his pedigree. You could even take a genealogy trip to the Labrador Peninsula with your favorite canine companion.
However, of the 70 million dogs currently living in the United States, most are not purebred. Owners of mixed breed dogs often rely on their own the best guess or that of a shelter staff member for insight into their dog’s ancestry. For many mutt owners, a canine family member was added after a chance encounter by the side of the road or after reading an online posting for a dog in need of a home. I found my own dog, Skyler, 11 years ago at an animal shelter in San Diego below a sign that read “Labrador Pit Bull mix”. A staff member mentioned that a local transient had previously owned her, but nothing else was known about her past.
As part of Darwin’s Dogs, I’m currently using genetics to better understand the origins of America’s mixed breed dogs. We have sequenced the DNA of 21 mutts and compared this DNA sequence to known purebred dogs. In this way we can identify what portion of a dog’s DNA matches specific known breeds. I am excited that my dog, Skyler, was selected for this study because it gives me a chance to better understand her origins.
photo credit: http://www.designermixes.org/
Many owners may believe that their mutt is a simple mix of 2 or 3 breeds – that’s certainly what I anticipated for Skyler, but looks can be deceiving. Every single dog in our study turned out to be a motley mix of at least 6 breeds. In fact, most of the dogs we looked at have ancestry from more than 12 different breeds. Statistically, we are now able to determine the breed ancestry with very high confidence. It is interesting to see how these breeds are not always obvious from the appearance of a dog!
Despite the guess of animal shelter employees, Skyler turned out to be a mix of at least 10 different breeds and she is less than 5% Labrador and Pit Bull. She is more Dalmatian than any other breed, but this purebred ancestor was likely a great grandparent. I hadn’t guessed that she was part Dalmatian, but now, looking at her more closely, I see a few Dalmatian-like spots on her chest. I also noticed that she resembles designer mixed breed dogs of her top two ancestries - Dalmatian and Rottweiler (called Rottmations). Previous genetic studies in dogs have focused almost entirely on purebreds, and I’m excited that our study is revealing new insights into the complex ancestries of mutts in America.