Pathway enrichment. Result of the pathway enrichment analysis. For each method applied to our data set, we plotted the pathway enrichment index (PEI). This index gives the fraction of KEGG pathways found enriched in at least one submode or cluster (see Methods). GraDe obtained a much higher PEI than PCA, k-means clustering or FunCluster. This indicates that sources obtained by GraDe map much closer to biological pathways.