Mutagény

Mutagény, often referred to as a mutagen, is an agent that increases the frequency of genetic mutations by altering DNA. Mutagens can act at the level of DNA sequence or structure and may affect germline cells, somatic cells, or both. They can be chemical, physical, or biological.

Chemical mutagens include alkylating agents that modify bases, base analogs that substitute for natural nucleotides, and intercalating compounds that distort the DNA helix, causing insertions or deletions during replication. Physical mutagens include ultraviolet and ionizing radiation; UV light induces pyrimidine dimers, while ionizing radiation causes breaks in DNA strands. Some mutagens are forms of oxidative stress or replication inhibitors. Biological mutagens involve infectious agents such as certain viruses that insert or disrupt genetic material.

Mutagenicity is assessed through assays such as the Ames test, which uses bacteria to detect mutations that restore metabolic function; results are used for initial screening of chemical safety. Not all mutations induced by mutagens are pathogenic; in some cases they may be neutral or even advantageous in evolution, though most mutations are detrimental or harmful to the organism. The effects depend on dose, exposure duration, tissue type, and DNA repair capacity.

Exposure to mutagens is regulated for human health and environmental protection. Long-term exposure to certain mutagens, especially carcinogens, is associated with an increased risk of cancer, but risk assessment involves considering exposure levels, genetic susceptibility, and other factors.