Growth dynamics in 96-well plates indicate that the E2 population is slower than the ancestor. Although much slower than wild-type (green), all populations other than E2 had increased their growth rate between generation 60 and 120 (light and dark blue). The E2 population, however, was slower than the EM ancestor (red) at both 60 and 120 generations (light and dark purple). Note that below a threshold OD600 of ~0.002, cultures other than E2 fail to recover, including one of the EM ancestors. Data represent the mean of three replicates on the plate.