Strengths and sequences analysis of the dnaQ mutators selected from kanamycin stress (KanR group), n-butanol stress (BtlR group), and acetate stress (AceR group). (A) Mutator strengths of the dnaQ mutators relative to the wildtype gene, based on the frequency calculation of rifamycin resistant colony generation. For better understanding and comparisons, weak mutators, medium mutators, and strong mutators are distinguished with light blue, marine blue, and dark blue. (B) Summary of the amino acids substitutions on sequences of all the dnaQ mutator genes isolated. The full length of the ϵ subunit sequence is divided into two parts by the black line, pointing to the ϵ186. Three red line marked the three conserved and essential regions for the 3′->5′ exonuclease activities. Amino acids substitutions are labeled with black bars and characters.