Figure 4.

TATA-containing genes exhibit greater expression levels and transcriptional plasticity than TATA-less genes. (a) Comparison of the expression levels (measured as the logarithmic transformation of the Fragment Reads Per billion) between TATA-containing and TATA-less genes for duplicates (red and orange boxes, respectively) and singletons (blue and white boxes, respectively). Differences were tested using the Wilcoxon rank test and significant differences are identified as * and **, for probabilities of P < 0.05 and P < 0.01, respectively. The percentage of genes with TATA-containing promoters for transcriptionally plastic and transcriptionally unaltered genes when S. cerevisiae is growing under four different stress conditions (ethanol, glycerol, lactate and oxidative stress in a medium supplemented with dextrose) was compared for duplicates (b) and for singletons (c). Significant differences between plastic and unaltered genes were identified using Fisheŕs exact test and are identified as ***, to indicate a probability of P < 2.2 × 10⁻¹⁶.