Fig. 3.

Fitness effects of evolved pykF mutations in the ancestor and a 20,000-generation clone isolated from the population in which they occurred. (A) Fitness effects of pykF mutations in the ancestor. (B) Fitness effects of pykF mutations in evolved clones. The A301S mutation evolved independently in the Ara–5, Ara+1, and Ara+5 populations, and thus its effects were measured in three evolved strains. Error bars indicate 95% confidence intervals (with n = 4 in each evolved background and n = 8 in the ancestral background). Asterisks indicate the significance of genetic background on fitness (two-tailed t test): ***P < 0.001, ** 0.001 < P < 0.01, * 0.01 < P < 0.05.