A set of genes derived by duplication of an ancestral gene, followed by independent mutational events resulting in a series of independent genes either clustered together on a chromosome or dispersed throughout the genome.

A group of genes, clustered or dispersed, with related nucleotide sequences.

A number of identical or related genes present in the same organism, usually coding for a family of related polypeptides.

a group of homologous genes with similar function

A collection of genes with similar or identical sequences, presumably of common origin. mutagen( myoot-uh-jen) [L. mutare, to change + genus, source or origin] A chemical or physical agent that interacts with DNA and causes a mutation.

A set of sequence-related genes within a genome that evolved from a single ancestral gene by gene duplication and subsequent mutations.

Multigene families occur when several similar genes exist in multiple copies in the same region of DNA. They are very similar and may differ by a few nucleotides. They occur in clusters and differ from tandem clusters.