Related to De novo mutation: back mutation, conditional mutant. [mu-ta´shun] 1. a permanent transmissible change in the genetic material. 2. an individual exhibiting such a change. point mutation a mutation resulting from a change in a single base pair in the DNA molecule. somatic mutation a genetic mutation occurring in a somatic cell, providing the basis for mosaicism. suppressor mutation the correction of the effect of a mutation at one locus by a mutation at another locus.