Some selective breeders can increase genetic variation by creating mutations. Mutations can occur spontaneously, but they can also occur with radiation and chemicals. Many mutations are harmful, however breeders do this because they want desirable characteristics not found in the original population. The small size of bacteria has been useful to radiate and poison all the organisms, therefore creating a higher chance of a mutation. Oil-digesting bacteria has been mutated in laboratories. Mutations are harmful and kill several organisms, but in the end a desired trait is achieved. Mutations have also created polyploid plants. Polyploid plants have many sets of chromosomes, they are usually fatal in animals. Banana’s and some citrus fruits are polyploid. I love banana’s! This mutations was a good call.