It seems that during reproduction particular genes are targeted for modification (mutation, deletion, insertion, etc.) given environmental inputs of either or both of the parents.
If a creature was fit given its environment, its seems there is little mutation. However, if the creature becomes less fit (i.e, due to increasingly becoming prey to a predator) it will undergo increased rate of mutation to find a successful adaption to the new environment. But it seems that the mutation is also targeted to particular genes that maybe most beneficial to mutate (i.e, to develop camouflage).
This begs the question - given environmental inputs, is there something that controls gene modification during reproduction? More specifically, is there a process that targets a specific gene or trait?