Intercalation of Base Analogs
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 stain to visualize DNA: the intercalated molecule fluoresces on exposure to ultraviolet light. EtBr may be incorporated directly into electrophoresis 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.