A spontaneous change in the genetic composition of an organism at the gene, chromosome, or genomic level. Mutations usually refer to alterations to new allelic forms, and represent new material for evolutionary change.

In genetics, a permanent, heritable change in the nucleotide sequence of a chromosome, usually in a single gene; commonly leads to a change in or loss of the normal function of the gene product.

are the changes of a gene from one allelic form to another (i.e., the nucleotide sequence changes).

Mutations is an indie rock album by Beck and was released in 1998. Though less successful on the charts than the preceding Odelay, Mutations established Beck as a progressive and innovative artist, for his mixture of far-ranging musical genres, including tropicalia, bossa nova, country and blues. The album's title is most likely a nod to an influential tropicalia band of the 1970s, Os Mutantes.

Mutations is an EP released by metal band Fight in 1994. It features live tracks and studio remixes from first album.

an imperfect test

a particularly difficult one