Since early in canine domestication, humans have been selecting individual dogs with desirable behavioral and physical traits to be founder breeding animals for the hundreds of dog breeds we have today. Early on, the traits selected for were often of great importance for their role as working animals. With time, as the world of dog fanciers took shape, dogs with particular physical traits of aesthetic value began to be the chosen bearers of future generations regardless of their ability to work. Unfortunately however, there are multiple examples of selected physical traits that are significant risk factors for disease.
One important example is a disorder seen in Rhodesian ridgeback (RR) dogs known as a dermoid sinus that has been associated with the characteristic “ridge” trait in the skin overlying the spine. In 2007, a large genetic duplication on canine chromosome 18 was identified as the underlying genetic cause of the ridge in this breed.2 Unfortunately, the same genetic duplication responsible for ridge formation has also been found to predispose RRs to formation of dermoid sinuses.1,2
Dermoid sinuses are tubular to round shaped cavitations in the skin often filled with hair and keratin that are present at birth. It ...