The notable extent of preservation of M9, M15 and M16 in all four networks (Figs. 2 and 3 and Supplementary Table 2) warranted further exploration. To begin to characterize these modules in terms of their constituent genes, we plotted the expression levels for the ten genes with the strongest average membership for each of these modules across all four networks (Fig. 4); these genes were consistently coexpressed in every network.
