«There has to be more systematic review, with control groups and treatment groups in
different canine populations — overweight versus pets with ideal body condition, and so on.
Previous studies indicate that some inherited disorders do not have significantly
different prevalence across both the purebred and mixed - breed dog
populations [6] which may represent ancient disease liability genes that preceded breed formation that are now distributed throughout the
canine population as a whole or reflect recent purebred contributions to mixed - breed individuals.