In the context of genetics, a transversion is a type of mutation where a purine (adenine or guanine) is substituted with a pyrimidine (cytosine or thymine), or vice versa. This contrasts with transitions, which involve the substitution of a purine with another purine or a pyrimidine with another pyrimidine. Transversions are considered more disruptive than transitions due to the structural differences between purines and pyrimidines.