Archives for July 1, 2013

Are There Risks for Genetic Disease with Cross-breeding?

Are There Risks for Genetic Disease with Cross-breeding?

Some people will say that there is little or no risk for genetic disease in crossbreeding and no need for genetic testing by virtue of the fact that the dogs are crossbred. I use Progressive Retinal Atrophy as an example to illustrate the potential genetic consequences of such breeding, but the premise and the potential risk for disease holds true for any possible genetic condition that affects dogs.

Progressive Retinal Atrophy (PRA) is an inherited progressive eye disease that affects the part of the eye called the retina.  Light striking special cells of the retina (primarily photoreceptor cells called rods and cones) leads to the creation of the picture that is seen by the brain.  The retina is often compared to the film of a camera.  PRAs can progress from vision impairment, to night blindness or to hesitancy in certain situations and lead ultimately to total blindness.  Total blindness in a PRA affected dog may not be recognized until they are taken to an unfamiliar environment while other dogs may be recognized far earlier due to dilated pupils, an attempt by the eye to let in more light, and eye shine that occurs when the retina ...