Figure 4.

Spectra of mutations generated in the cro gene during in vitro replication by pol V or by pol III holoenzyme. The 201 nt of the coding region of cro are shown. Mutations generated by pol V are shown above the cro sequence, whereas mutations generated by pol III holoenzyme are shown underneath the sequence. Δ, −1 deletion; M, −2 deletion; V, +1 insertion next to the marked nucleotide. The identity of the inserted nucleotide is shown in parentheses, unless it is identical to the template nucleotide after which it was inserted. W, +2 insertion. In addition to mutations in the coding region, eight mutations were found upstream to cro: for pol V, two C → A and one each of T → G, T → A, C → T, +T; for pol III holoenzyme, C → T and G → T, one each.