The genetics that give various breeds their particular attributes (like the spots on a Dalmatian or the short legs of a Dachshund) are often the result of inbreeding. New research has demonstrated that the majority of dogs are highly inbred. Unfortunately, the study findings indicate that inbreeding of dogs contributes to an increase in disease and health care costs throughout their lifespan.
The researchers partnered with Wisdom Health Genetics, a world leader in pet genetics, to obtain the largest sample size possible for analysis. Wisdom Health’s database is the largest dog DNA database in the world, helping researchers collect data from 49,378 dogs across 227 breeds — primarily from European sources.
Some Dog Breeds are More Inbred than Others
What makes a dog breed more inbred than others? The lead researcher of the study says that it is often a combination of a small founding population followed by strong selection for particular traits in a breed. The selection of particular traits is often based on appearance rather than purpose.
Inbreeding Adversely Affects Health
The average inbreeding based on genetic analysis across 227 breeds was close to 25%, or the equivalent of sharing the same genetic material with a full sibling. These are levels considered well above what would be safe for either humans or wild animal populations. In humans, high levels of inbreeding (3-6%) have been associated with increased prevalence of complex diseases as well as other conditions.
“Data from other species, combined with strong breed predispositions to complex diseases like cancer and autoimmune diseases, highlight the relevance of high inbreeding in dogs to their health.”
-Dr. Danika Bannasch, veterinary geneticist, University of California, Davis
Journal Reference: Danika Bannasch, Thomas Famula, Jonas Donner, Heidi Anderson, Leena Honkanen, Kevin Batcher, Noa Safra, Sara Thomasy, Robert Rebhun. The effect of inbreeding, body size and morphology on health in dog breeds. Canine Medicine and Genetics, 2021; 8 (1) DOI: 10.1186/s40575-021-00111-4