Maxam, Allan M.; Gilbert, Walter

Proceedings of the National Academy of Sciences of the United States of America (1977), 74(2), 560-4 CODEN: PNASA6; ISSN: 0027-8424. English.

DNA can be sequenced by a chem. procedure that breaks a terminally labeled DNA mol. partially at each repetition of a base. The purine-specific reagent is dimethyl sulfate; the pyrimidine-specific reagent is hydrazine. The lengths of the labeled fragments then identify the positions of that base. Reactions are described that cleave DNA preferentially at guanines, at adenines, at cytosines and thymines equally, and at cytosines alone. When the products of these 4 reactions are resolved by size, by electrophoresis on a polyacrylamide gel, the DNA sequence can be read from the pattern of radioactive bands. The technique will permit sequencing of ≥100 bases from the point of labeling.