As people peer into DNA for clues to health and heritage, man’s best friend is under the microscope, too. Genetic testing for dogs has surged in recent years, fueled by companies that echo popular at-home tests for humans, offering a deep dive into a pet’s genes with the swab of a canine cheek. More than a million dogs have been tested in little over a decade. The tests’ rise has stirred debate about standards, interpretation and limitations. But to many dog owners, DNA is a way to get to know their companions better. “It put some pieces of the puzzle together,” says Lisa Topol, who recently tested her mixed-breed dogs Plop and Schmutzy. Plop was the top-scoring mixed-breed, and Schmutzy also competed, in Saturday’s agility contest at the Westminster Kennel Club dog show. Judging toward the coveted best in show prize begins Monday. A test by Embark – which this fall became Westminster’s first DNA-testing partner – confirmed Topol’s guess that her high-octane pets are more Australian cattle dog than anything else. But Schmutzy’s genetic pie chart had surprise ingredients, including generous amounts of Labrador retriever and Doberman pinscher. Huh? Topol thought at first. And then: Maybe Schmutzy’s love of water and fetching is her inner Lab coming out. And doesn’t she walk a bit like a Doberman? “They are the dogs that they are … They’re unique, and they’re special,” said Topol, a New York advertising executive. But the testing “makes me understand them better.” Canine DNA testing for certain conditions and purposes goes back over two decades, but the industry took off after scientists mapped a full set of dog genes and published the results in 2005. Wisdom Health, part of pet care and candy giant Mars Inc., launched a breed-identification test in 2007, added a health-screening option a few years later and says it has now tested over 1.1 million dogs worldwide. Numerous other brands are also available. Mass-market tests have fueled research and helped animal shelters attract adopters by providing more information about prospective pets. DNA can back up purebred dogs’ parentage and help breeders try to eliminate certain diseases. The technology has been used to identify dogs whose owners don’t pick up their droppings, to pursue accused biters and to free a Belgian Malinois from dog death row after he was accused of killing a Pomeranian in Michigan. And some veterinarians feel DNA testing enhances care. “I want to know as much about my patients as possible,” says Dr. Ernie Ward, a veterinarian and TV personality in Ocean Isle Beach, North Carolina. He recommends testing all puppies. But qualms about the dog DNA boom spilled into the prestigious science journal Nature last year. “Pet genetics must be reined in,” a Boston veterinarian and two other scientists wrote. Their commentary opened with a troubling story: a pug being euthanized because her owners interpreted DNA results to mean she had a rare, degenerative neurological disorder, when in fact her ailment might have been something more treatable. “These (tests) should be used in a limited way until we get a lot more information,” says co-author and vet Dr. Lisa Moses. One concern is that tests can show genetic mutations that are linked to disease in some breeds but have unknown effects in the breed being tested. It also may be unclear how often dogs with the mutation ultimately get sick. That means tests, in themselves, can’t necessarily tell pet owners how much they should worry. Or tell breeders whether a dog shouldn’t reproduce. Some in dogdom fear that DNA test results could keep animals from passing on otherwise good genes because of an ambiguous possibility of disease. Published in Daily Times, February 12th 2019.