Intercalation of Base Analogs
are histological stains with
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 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.