Environmental factors can result in the incorporation of mutations into DNA. Many mutagenic compounds and various forms of radiation lead to mutations through the activity of an error-prone DNA repair mechanism. Which of the following causes mutations by the process of dimerization of adjacent pyrimidines?

Question

Quizplus · Accepted Answer

Ultraviolet light causes mutations by inducing the formation of pyrimidine dimers, particularly thymine dimers, in DNA.  Pyrimidine dimers are formed from thymine or cytosine bases in DNA via photochemical reactions. Ultraviolet light induces the formation of covalent linkages generating cyclobutane pyrimidine dimers, CPDs (including thymine dimers). Pyrimidine dimers can be repaired by a process termed photoreactivation. This requires photolyase enzymes that directly reverse CPDs following the absorption of fluorescent light or sunlight. This absorption enables the photochemical reactions to occur, which results in the elimination of the pyrimidine dimer, returning it to its original state.

Environmental Factors Can Result in the Incorporation of Mutations into DNA