Distribution of genes among expression clusters. Nine clusters, grouped according to their regulation by CRE1 (i.e. repressed, induced, or independent) were obtained from the microarray results (from A to H, and X). The color code indicates the effect of the growth rate: blue specifies clusters of genes affected only by a high growth rate (dark blue indicates upregulation, light blue downregulation). Purple specifies the genes upregulated at a low growth rate. Gene clusters whose expression is not influenced by the growth rate are given in orange. The percentages indicate the fraction of the total genes that is present in the respective cluster and the number of genes in each cluster is specified in parentheses.