Figure 2.

(a) Primer extension opposite an abasic site model in a random flanking sequence library of 16 possible sequences. The abasic site model F and its flanking random sequence are in bold. The EcoRI restriction sites are italicized, the 15-mer primer is underlined. The control template is identical to the F-containing template, except that F was not incorporated. (b) Formation of the sequence tags for oligomerization. Polyacrylamide gel electrophoresis of the products of PCR amplification of the bypass products of the abasic site and control sequence followed by restriction digestion with EcoRI. PCR primers are underlined.