If the environment affects the course of a disease/trait, then that proves the trait is not genetic. This is the twin of myth #3 & just about as common. Environment is PART of the genetic inheritance of a person or dog: a certain enviroment is necessary for each and every gene to get "turned on" & expressed. They work TOGETHER, not in opposition. For example, if a dog with genes for hip dysplasia is fed carefully with low protein & low calcium and kept from any real exercise, this dog may express the genes later and with less obvious original bone changes than the pup who eats a ton & runs around unsupervised. Both will end up with arthritis, likely, & both EQUALLY are going to pass on their genes for this crippling disease to their offspring. The first dog is just less "honest" about what sort of genetic parent he really is. Diet & supplements can mask the effects of disease & even control them--think about adult onset diabetes which is usually controlled wholly by diet. But disease controlled by environmental manipulation isn't a cure & the offspring of dogs who need enzyme supplements, for example, are going to display the same kind of pancreatic insufficiency their parents did, even if none of these animals are ever properly diagnosed and their genetic defect isolated or even admitted. As Richard Dawkins says: "A gene's meaning is context dependent." |
BluePink 
