Figure 5.

Formation of −1 and −2 mutations in specific sequence contexts. (a) Gel analysis of the full-length (0), and −1 and −2 deletion products in the bypass of homogeneous substrates in selected sequence contexts. C refers to the control sequence NN lacking the abasic site whose full-length product corresponds to a −1 deletion. The EcoRI sequence in the primer was mutated (G→T) to prevent cleavage at this site and retain the 5′-³²P label on the bypass products. (b) Frequency of substitution, −1 and −2 mutations as a function of sequence context.