Introduction to Genetic Testing

Photo by Kikko Kåhre.

Breeders have always used whatever information is available to them to try to make the best informed decisions in their planned matings. However, the day is coming when breeders are going to have MORE information to consider when planning breedings: We are on the verge of being able to choose sire and dam not only on the basis of phenotype (the way the dog looks, moves, and acts), but also genotype (the blueprint you cannot see, which predisposes the dog to the development of future traits or diseases)—of the dog itself and of its relatives—for genetic conditions in addition to Factor VII. While we must all strive to breed the healthiest dogs possible, we must also preserve the gene pool that we still have.


To quote geneticist Dr. Jerold Bell, “Genetic tests do not determine which dogs get bred, only which dogs they get bred to.” While we must all strive to breed the healthiest dogs possible, we must also preserve the gene pool.

All breeders should take the information they get on genetic disease genotypes and add it to all the other information they have to weigh when it comes to picking a mate. Genetic testing is a tool and needs to be used with all of the other tools in a breeder’s toolkit. Genetic testing should not be used in isolation! For instance, a short list of desirable traits in a potential mate might be:

  • Desired/complementary conformation features
  • Desired temperament in mate and family
  • Desired coursing/hunting ability in mate and family
  • Proven ability to convey desired traits to offspring, if any exist
  • Tendency for long life in family
  • History of good health in mate and family
  • Desired Factor VII genotype
  • Desired other genotypes, as tests become available.

Many more items can be added to this list. But just as we now make trade-offs among phenotypic factors, we are going to have to make trade-offs among genotypic factors and among phenotypic and genotypic factors. In a rare breed such as ours, none of us will have access to enough potential mates to avoid making such trade-offs. A breeder will have to weigh desirable conformation against a desirable array of health-related genetic factors. Do they go to a mate with ideal conformation that complements their dog perfectly, but accept that it carries an undesirable genetic health variant? And does it matter how undesirable the genetic health variant is? Or do they compromise on conformation, or temperament, or coursing ability in order to avoid an undesirable genetic variant? This is where we are or soon will be, and there is no easy answer. But even if an undesirable genetic variant is passed on in one breeding, the long-term goal of every breeder should be to reduce the incidence of these variants from the breed WITHOUT reducing our gene pool. So no otherwise worthy dog should be eliminated from breeding because of an undesirable genotype. Instead, that dog should be bred to a Deerhound that is normal for that genotype.

Another important thing to consider is these undesirable genetic health variants only INCREASE THE RISK that an affected dog will have the disease. So, for instance, when Dr. Carlos Alvarez, our osteosarcoma researcher, spoke at the 2018 national specialty, he talked about dogs with some osteosarcoma variants being more than nine times more likely to contract osteosarcoma than dogs without them. However, some dogs, despite having those variants, will never develop osteosarcoma. The vast majority of disease variants, both in dogs and in people, only confer increased risk. We are all already familiar with this phenomenon in our breed with Factor VII deficiency, for instance, as many affected dogs don’t have bleeding problems during surgery, while others do.

Below please find the link for the Health & Genetic Committee’s position statement on Factor VII. We will be working with the best available data from our researchers and the literature to create a series of these statements as new genetic tests become available. If you have any questions, we encourage you to get in touch with any member of the Health & Genetics Committee.

Genetic Testing in Deerhounds — Factor VII

Our blog also has more information: see the Recommended Health Test and Genetic Testing Information categories.