A single-reaction method for DNA sequence determination.

A chemical method for the determination of DNA sequence is presented. Heating of DNA, labeled at a single 3' extremity, in the presence of formamide results in efficient cleavage of phosphodiester bonds 3' of A, G, and C residues. The relative efficiency is A = G greater than C. The bias between A and G is solved by a simple pretreatment (photoreaction in methylene blue) followed by heating in formamide. The entire procedure does not require any intermediate purification step or handling of hazardous chemicals and allows determination of the sequence on only two electrophoretic lanes. Its simplicity and rapidity favor automatization.