Overrepresentation maps of six selected gene sets containing between N
= 157 and 472 genes. Overrepresentation in each tile of the mosaic is calculated in units of log(pHG) using the hypergeometrical distribution and color-coded (maroon > red > yellow > green > blue). White areas indicate metagenes not containing genes from the respective set). Strongest overrepresentation of the different gene sets is found in different regions of the SOM (see red circles). Overrepresentation can be concentrated within one or a few adjacent metagenes (e.g. nervous system, panel b) or spread over different disjunct regions of the map (apoptosis, panel d).