Figure 1.
Bacterial genome subtractive DNA method. Solid lines represent AluI-digested tester and driver DNA fragments. Boxes represent outer part of PCR adaptors, which lack phosphate groups at their 5′ ends. Adaptors 1 and 2 are identical near their 5′ ends but differ near their 3′ ends. Note that after recessed 3′ ends are filled, types a, b, and c molecules having adaptor 2 are also present, but are not shown. This method is adapted from the subtraction subtractive hybridization method for studies of mRNAs in eukaryotes (18, 19).