Average fitness effects and standard deviations of reconstructed heterozygous pgm1 and alg9 mutations (closed circles) compared to evolved clones containing those mutations plus three to nine additional mutations (open circles). Replicate measurements are plotted as gray circles. Note there are two clones from different populations with an alg9-S230R mutation. Asterisks (*) represent statically significant differences between fitness effects of evolved clones and fitness effects of reconstructed clones (Welch’s modified t-test): pgm1-T231A (p < 0.0001, t = 36.1, df = 28.9); pgm1-G514C (p < 0.0001, t = 11.8, df = 18.4); pgm1-T521K (p < 0.0001, t = 33.8, df = 27.3); pgm1-R64C (p < 0.0001, t = 52.9, df = 24.3); pgm1-D295N (p = 0.05, t = 2.10, df = 19.9); alg9-S230R (left) (p < 0.0001, t = 53.7, df = 49.7); alg9-S230R (right) (p < 0.0001, t = 44.1, df = 46.1).