noun, plural: transversions
(genetics) A small-scale mutation characterized by the replacement of a purine by another pyrimidine (e.g. A → C) or a pyrimidine by another purine (e.g. T → G)
In genetics, transversion is a type of mutation. Mutation is defined as a change in the nucleotide sequence of a gene or a chromosome. Based on the effect of mutation on the gene structure, mutations may be: (1) small-scale mutations or (2) large scale mutations. Small-scale mutations are a type of mutation where one or few nucleotides of a gene are affected. They are further classified as follows: (1) substitution mutations, (2) insertion mutations, and (3) deletion mutations. Substitution mutations are a type of mutation in which a nucleotide is substituted with a different nucleotide. Depending on the type of nitrogenous base involved, this type of mutation may be categorized as transition or transversion. A transition is a substitution of a purine nucleotide by another purine (A → G), or of a pyrimidine by another pyrimidine (C → T). In contrast, transversion is the substitution of a purine by a pyrimidine, or of a pyrimidine by a purine.
Since transversion mutation involves only one nucleotide, it may also be a sub-type of point mutation.
- transition (genetics)