Mutagenesis

Abstract

Mutagenesis, the formation of mutations, can occur as a result of exposure to DNA-damaging (genotoxic) agents, or it can occur spontaneously in cells. Genotoxic agents may be present naturally (e.g., solar UV, natural radionuclides) or produced anthropogenically. Damage to DNA is of concern because it may lead to irreversible effects that can affect fitness of organisms. DNA damage can result in a variety of mutations. This article discusses the types of pollutant-induced DNA damage that may lead to mutations, repair of DNA damage, the categories of mutations, environmental factors that can affect formation of DNA damage and mutations, and effects of DNA damage and mutagenesis on fitness parameters, and how such effects might be translated in higher-level effects (population, community, and ecosystem). DNA lesions include damage to DNA bases or to the deoxyribose sugar, including chemical adducts, base oxidations, base loss, strand breakage, damage induced by UV light, and DNA cross-links. Mutations are caused by unrepaired or misrepaired DNA, and can include point mutations, frameshift mutations, and chromosomal mutations. These mutations may be harmful (deleterious), neutral (silent), or, in rare cases, beneficial to cells or organisms. Deleterious mutations may affect fitness of individuals, eventually resulting in population-level effects or effects on communities and ecosystems.