Intercalation of Base Analogs

    Acridine dyes are histological stains with a planar three-ring structure that resembles a purine / pyrimidine base pair. If these base analogs slip into the DNA molecule between two adjacent base pairs, the intercalated molecule may cause DNAPol to "stutter" and copy the molecule as an extra base pair. This introduces a frameshift mutation.

    Ethidium bromide (EtBr ) is widely used in molecular biology as a specific dye for staining DNA: the intercalated molecule fluoresces on exposure to ultraviolet light. EtBr may be incorporated into electrophoretic gels, or the gel may be stained after running. In Bio2250 labs, care should always be taken not to expose oneself to either gels or buffer containing EtBr.