FIG 2.

Sequence changes in thyA. The locations of spontaneous mutations in the CC107 wild-type background are shown above the DNA sequence (black); the locations of CPR-derived mutations in the wild-type BW25113 background (red) and the CC107 background (black) are shown below. The letters represent base substitutions, the circles indicate the A·T→T·A base substitution at the hot spot at bp 131, the diamonds indicate deletions of a single base pair, the triangles indicate insertions of a single base pair, the solid lines are aligned with deleted base pairs, and the arrows indicate the locations of insertions. The numbers with plus signs in parentheses show the number of additional mutations at any given site that appeared more than once in a sample of four from the same culture.