insertion mutant Insertion a mutant genotype in which one or more extra nucleotides have been added into the DNA. Insertions may be reversible, particulary if caused by transposable elements. They may alter the reading frame of a gene, or may cause large scale additions of genomic DNA. Adapted from: http://ncicb.nci.nih.gov/xml/owl/EVS/Thesaurus.owl#C19295 Insertion Mutation Abnormality Mutation, Insertion mutant mutant