Should You Test Your Dog's DNA?
Thanks to popular television shows, many people have become familiar with the use of DNA testing for solving crimes. Outside the realm of criminology, however, DNA testing can provide important information about identification, parentage, and even the presence of certain diseases or conditions. This technology can reveal similar information about dogs, giving owners a better understanding of their dog's identity.
The Role of DNA
The genetic makeup of all living organisms depends on DNA, which is a large molecule made up of two long strands of compounds called nucleotides. Each nucleotide is linked to another on the opposite strand, creating the characteristic spiral ladder configuration. DNA segments compose genes, which determine an organism's individual traits. Dogs have about 20,000 to 25,000 genes located on 78 chromosomes. By comparison, humans have about 19,000 genes located on 46 chromosomes.
Types of DNA Tests
DNA testing can show you a variety of interesting and important information about your dog. These are the types of testing that are currently available.
This test verifies the sire and dam of a purebred dog. Samples for the sire and dam must also be submitted if they're not already on file. Breeders can use this test to offer DNA-certified pedigrees for their litters.
Breed ancestry shows all the breeds in a mixed-breed dog's ancestry for up to three generations. The accuracy of this test depends on the extent of the laboratory's database and the number of breeds in the dog's ancestry. For example, the results are more accurate for a dog who's a mix of just a few breeds rather than a dog who has multiple mixed-breed ancestors. This is a fun and popular test for curious owners of mixed-breed dogs.
Inherited Disease Testing
Disease testing shows whether the dog carries genes that are responsible for certain inherited diseases, such as von Willebrand disease (Doberman Pinschers), exercise-induced collapse (Labrador Retrievers), and many others. A positive test doesn't always mean that the dog has the disease, but it shows breeders that he is a carrier and shouldn't be bred.
Inherited Trait Testing
This test determines if the dog carries genes that are responsible for certain inherited traits, such as coat color, length, and texture. As with inherited disease testing, a positive result indicates that the dog carries the trait even if he doesn't exhibit it. For example, this test allows breeders to tell if a dog carries the "long hair gene," because a longer coat is considered a fault in competitions for some breeds.
Genotyping shows the dog's complete DNA profile for identification purposes. This test does not determine the breed makeup of mixed-breed dogs, nor does it provide information about inherited diseases or traits. Genotyping secures a permanent ID for your dog in case he is lost or stolen. Some breeders also use genotyping to keep DNA records of dams and sires in case they need to perform parentage verification of their puppies. The American Kennel Club (AKC) offers genotyping and parentage verification for AKC-registered dogs and maintains a database of the results.
How to Test Your Dog
Various companies, laboratories, and other organizations conduct DNA testing on dogs. In most cases, the owner can order a test kit, obtain a DNA sample by swabbing the inside of the dog's cheek, apply the swab to a designated place in the kit, and mail the kit out for analysis. The test results are returned by e-mail or standard mail in about two to four weeks, and the cost for each test ranges from about $60 to $100.
Karla S. Rugh, DVM, PhD, is a practicing veterinarian, consultant, and writer in Rocheport, Missouri. She has twice received the National Institutes of Health Research Service Award.