You can swab the inside of your dog’s cheek to find out whether they have any genes linked to certain canine diseases — but it may be best if you don’t. These services have flaws similar to those of human DNA tests, including false positives and false negatives.
Two veterinarians and a geneticist, writing in science journal Nature, tell the story of a 13-year-old pug they’ll call Petunia, who began to have trouble walking and controlling her bowels. Her owners had her euthanised after learning she had a mutation for an incurable neurodegenerative disease — but her condition could have been caused by something more benign and treatable.
Many of the tests are based on preliminary research that hasn’t reliably connected the gene to a health condition, or where the connection is only considered solid in some breeds. In Petunia’s case, for example, only one in 100 dogs with her result are likely to ever develop the associated disease.
False negatives are a problem, too. If there are multiple mutations that cause a certain disorder, but a testing company only looks for one of them, the results may say (or imply) that the dog doesn’t have that condition.
For any medical test, for yourself or your pet, you have to ask: What will I do if this result is positive? What will I do if this result is negative? So far, genetic tests for dogs just aren’t reliable enough to be the basis for serious veterinary health care decisions. The same is true of consumer-level tests for human genetics as well, so the dogs aren’t alone.