Somatic mutation

A somatic mutation is a mutation in the body's cells that do not become eggs or sperm. By definition, the cells of the germline (see also germline mutation) are not affected by the mutation. Mutations in somatic cells are not hereditary and only affect the person in whom the mutation occurs.

A special form is represented by immediate postzygotic mutations, which occur in the zygote or the first division stages. These mutations are distributed only to certain germ layers and thus cause the emergence of a genetic mosaic.