For each human brain data set, modules of coexpressed genes were identified by unsupervised hierarchical clustering on the basis of topological overlap (see Methods and refs. 15,18 for additional details regarding network construction and module identification). We identified 19 modules in CTX, 17 modules in CTX_95, 23 modules in CN and 22 modules in CB (Fig. 1 and Supplementary Fig. 2 online). To determine whether modules from different networks were composed of the same genes, we calculated the overlap and corresponding hypergeometric probability for each possible pair of modules (Supplementary Table 2 online). The majority of the gene coexpression modules that we identified in cerebral cortex were found in both CTX and CTX_95 (Fig. 2), with the extent of overlap ranging from 36% (module 19 (M19), P = 3.8 × 10−4) to 87% (M9, P = 1.9 × 10−68). To provide additional cross-platform validation for these findings, we also analyzed a microarray data set generated from human cerebral cortex samples using Illumina HumanRefseq-8 microarrays28 (CTX_ILMN). A majority of the gene coexpression modules that we identified in CTX were found in
