Fig. 1

Schematic illustration of digital and analog control. The different levels of system information. Part (a) shows the positions of genes/operons on the circular chromosome and the regulatory interactions mediated by transcription factors. These are analyzed separately in terms of the transcriptional regulatory network (b), which contains all interactions mediated by transcription factors, and the gene proximity network (c) contains links between two genes/operons if their distance on the chromosome is smaller than a certain threshold. Transcriptome data are then mapped onto these two networks in order to quantify the corresponding strengths of digital and analog control (d)