Fig. 5

Time-series analysis of the mutation fixation. a Timing of mutation fixation events in strain F. To identify the timing of mutation fixation, genomic DNA samples obtained at 12 different time points (216, 384, 576, 744, 888, 1056, 1224, 1392, 1584, 1824, 1968, and 2232 h after inoculation) were applied to Sanger sequencing. For each of the 5 identified mutations, the results of the Sanger sequencing is presented as a solid or dotted line. The solid line indicates that the mutation was fixed in the population at the corresponding time point, while the dashed line indicates the case of two peak signals, which indicates polymorphism in the population with and without the mutation. For example, in cells at 576 h after inoculation, only some have mutations in relA and cspC. b Specific growth rates of cloned E. coli cells with and without cspC and relA mutations under ethanol stress condition. Each bar represents the specific growth rate of an isolated clone, which were obtained from strain F cell populations at 576 h. " + " and "-" mean with and without the corresponding mutation, respectively. Blue, green, and red bars represent the growth rates of clones without mutations, that with cspC mutation only, and with cspC and relA mutations, respectively. Error bars indicate standard deviations calculated from three independent cultures