Effect of carbon source on expression profiles of the commonly-used ACT1 and genes of interest. Normalized expression of ACT1 and GPH1, GSY2, SGA1 in sample set "A" (n = 9). This set includes 5 samples selected during growth on glucose (grey, see legend from Figure 5) and 4 characteristic samples from growth on galactose (blue): early exponential phase (respiro-fermentative), entry in the diauxic shift (disappearance of galactose), mid of post-diauxic (respiratory) growth, and 3 days stationary phase. The exponential phase sample on glucose was used as calibrator for this sample set. Normalization was performed using the three most stable genes (NF(UBC 6, TAF 10, ALG 9), dashed bar), the geometric mean of ACT1, PDA1 and IPP1 (NF(ACT 1, PDA 1, IPP 1), empty diamond) or ACT1 alone (NF(ACT 1), black diamond). Normalized expression data and error bars calculated as described in Figure 5. For the sake of clarity, we did not plot standard deviation of ratios obtained from NF(ACT 1, PDA 1, IPP 1).