Mutation

1. 
   The act or process of being altered or changed.

2. An alteration or change, as in nature, form, or quality.

3. A sudden structural change within a gene or chromosome of an organism resulting in the creation of a new character or trait not found in the parental type.

4. The process by which such a sudden structural change occurs, either through an alteration in the nucleotide sequence of the DNA coding for a gene or through a change in the physical arrangement of a chromosome.

5. A mutant.