mutation

noun

• 1the action or process of mutating:the mutation of ethnic politics into nationalist politics his first novel went through several mutations

• 2the changing of the structure of a gene, resulting in a variant form that may be transmitted to subsequent generations, caused by the alteration of single base units in DNA, or the deletion, insertion, or rearrangement of larger sections of genes or chromosomes.
• a distinct form resulting from a change in the structure of a gene.

• 3 Linguistics regular change of a sound when it occurs adjacent to another, in particular.
• (in Germanic languages) the process by which the quality of a vowel was altered in certain phonetic contexts; umlaut.
• (in Celtic languages) change of an initial consonant in a word caused (historically) by the preceding word. See also lenition.