Fig. 1.

Representative trajectories showing changes in fitness during the evolution of the four E. coli strains discussed. (A, Top Left; Parent) Two lineages of nonrecoded ECNR2 (engineered from E. coli MG1655 K-12). (A, Top Right; Recoded) Two lineages of recoded C321.∆A (321 UAG→UAA and RF1⁻). (A, Bottom Left; Recoded.∆RF1) Four lineages of recoded C321.∆A-v2 (C321.∆A with engineered reversion of some off-target mutations that occurred during recoding). (A, Bottom Right; Recoded.∆RF1-v2) Two lineages of recoded C321 (C321.∆A with prfA gene restored). (B) Ancestral and final doubling time measurements sampled from all lineages of Parent (blue), Recoded (red), Recoded.∆RF1 (yellow), and Recoded.∆RF1-v2 (green).