Mutagen

A physical, chemical, or biological agent that increases the frequency of genetic mutations. Mutagens can alter DNA directly or disrupt the processes that copy and repair it.

DNA damage: Alterations to DNA structure that can interfere with replication, transcription, or chromosome stability. Many mutagens raise mutation rates by damaging DNA bases or its backbone.
Ames test: A bacterial assay that screens chemicals for their ability to cause mutations. It provides a widely used initial screen for potential chemical mutagens.
Ultraviolet radiation: Electromagnetic radiation with wavelengths shorter than visible light that can damage DNA. UV exposure can create pyrimidine dimers that cause mutations if unrepaired.
Point mutation: A mutation affecting a single nucleotide position in DNA. Many mutagens produce substitutions at individual bases.
DNA replication: The cellular process that copies DNA before cell division. Replication can turn unrepaired mutagen-induced damage into permanent sequence changes.
Mutagenesis: The generation of genetic mutations, occurring spontaneously or through induced exposure. Mutagens are agents that increase the rate of this broader process.
Ionizing radiation: Radiation energetic enough to remove electrons from atoms and molecules. It can break DNA strands and generate reactive molecules that damage genetic material.
Frameshift mutation: A DNA insertion or deletion that shifts the reading frame of a coding sequence. Some mutagens cause insertions or deletions that alter downstream protein coding.
DNA repair: Cellular pathways that detect and correct damage or errors in DNA. Repair systems counteract mutagens, while repair failures can magnify their effects.
Site-directed mutagenesis: A laboratory method for introducing a chosen genetic change at a specific DNA site. Unlike exposure to a mutagen, this method targets a planned sequence alteration.

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