EXPERIMENTAL FIGURE 6-19 A specific target sequence in genomic DNA can be amplified by PCR for use in cloning. Each primer for PCR is complementary to one end of the target sequence and includes the recognition site for a restriction enzyme that does not have a recognition site within the target region. In this example, primer 1 contains a BamHI recognition sequence, whereas primer 2 contains a HindIII recognition sequence. (Note that for clarity, in any round, amplification of only one of the two strands—the one in brackets—is shown.) After amplification, the target segments are treated with appropriate restriction enzymes, generating fragments with sticky ends. These fragments can be incorporated into complementary plasmid vectors and cloned in E. coli by the usual procedure (see Figure 6-14).