Identification of DNA adducts at specific locations by sequencing techniques

1. A simple procedure for the accurate identification of the positions of adduct formation when viral M13mp18 single stranded DNA is treated with chloroacetaldehyde (CAA) is presented. 2. The normal dideoxy sequencing reaction protocol was employed except no dideoxy nucleotides were used to cause chain termination. 3. Instead, the CAA adducted bases of the template DNA act as points of polymerase fall off causing the appearance of bands of DNA sequencing gel autoradiographs marking locations where adduct formation may have occurred.