Karlin,
I see what you are saying, but you should be aware that there is no genetic mechanism for evolution (other than random mutation). Mutation by its very nature is not something planned - it occurs because of an outside factor - something has gone wrong in the genetic copying - a mistake has occured. As such there is no "gene" for genetic change. Genetic change is not part of genetics - genetics preserves genetic information as best it can. Sometimes (very very rarely) this process goes wrong and we get mutation.
Evolution is not a biological or genetic "mechanism". Evolution merely says that in the process of trying to survive as best they can, and preserve their genes as best they can, very very rarely mistakes occur in the genetic copying process (genetic mutation) due to random outside factors. These random very rare mistakes are the (only) thing which leads to genetic diversity according to evolution.