Adaptive Evolution of the Lactose Utilization Network in Experimentally Evolved Populations of Escherichia coli
A) Steady state Plac-GFP levels (RFU) are shown for evolved clones grown in the presence of 100 µM TMG. Clones are divided into categories by evolution environment: Glu, Lac, G+L and G/L. Markers of the same color denote clones recovered from the same evolved population. Data points are the average of two independent replicates. As a reference, data for six independent ancestral (Anc) samples is also shown. B) Native lac promoter activity for the ancestor, evolved clone G+L3-1 and the ancestor with lacI and lacO1 mutations. Basal promoter activity was measured for strains grown in the absence of inducer, and maximum promoter activity was measured in the presence of saturating levels of inducer.