Mutation: Induced Mutations

H. J. Muller showed in 1927, working with Drosophila, that X-rays induce mutations, including sex-linked recessive lethal mutations, which he detected with his ClB method.
For this discovery of the production of mutations by X-ray irradiation, Muller received the Nobel Prize in Physiology or Medicine in 1946.
Cytoplasmic inheritance (Correns) and recombination of linked genes as such were not awarded Nobel Prizes; genetic engineering is a technology rather than a single discovery.
So the discovery that X-rays induce sex-linked recessive lethal mutations resulted in a Nobel Prize.