Clusters of genes that are coexpressed at specific growth rates from 0.02 to 0.33 per hour. (a) The transcript levels of differentially regulated genes are shown as transformed values between -1 and 1, where 0 indicates the average expression level over all six specific growth rates (μ = 0.02, 0.05, 0.1, 0.2, 0.25, and 0.33 per hour). The average transcript level within a cluster is indicated by the curve and the error bars give the standard deviation on the transcription profiles (clusters can be found in Additional data file 3). The 13 clusters originate from 27 clusters that were reduced manually (Additional data file 2). This was done by merging very similar clusters (clusters close in the dendrogram and discarding clusters that appeared to arise from experimental variation). Finally, ORFs that could not be assigned to a cluster with at least 80% probability (Pa < 0.20) were discarded and collected into a 'trash' cluster 14 together with the discarded clusters. (b) shows the expected distribution of ribosome related genes (black bars) and the actual distribution of ribosome related genes (white bars) in the 13 clusters.