Mutagén

Mutagén (mutagen) is any physical, chemical, or biological agent that increases the frequency of genetic mutations in DNA. Mutagens can affect germ cells or somatic cells, and the resulting mutations may be detectable in offspring if germ cells are affected. Some mutations are neutral, others deleterious or occasionally advantageous in an evolutionary context.

Mutagens are classified by their origin: physical mutagens such as ionizing radiation (X-rays, gamma rays) and ultraviolet light; chemical mutagens including alkylating agents (for example, mustard gas derivatives), nitrosamines, and intercalating compounds; and biological mutagens such as insertional mutagens from viruses or transposons that disrupt DNA sequence or regulation.

Mechanisms include DNA strand breaks, cross-linking, base modification, and replication errors; some provide altered bases that mispair during replication; defects in DNA repair pathways can amplify mutagenic effects. Resulting mutations include point mutations, insertions, deletions, and chromosomal rearrangements.

Mutagens are studied to assess chemical safety and understand gene function. In research, mutagens induce mutations to create model organisms or to map gene function. The Ames test is a widely used bacterial assay to screen compounds for mutagenicity. Not all mutagens are carcinogens, but many carcinogens are mutagenic.

Historically, the concept of mutagens emerged with work by Hermann J. Muller and others showing that X-rays and other agents increase mutation rates in model organisms, laying the groundwork for modern mutagenesis and toxicology.