Classification of 198 differentially expressed genes in the discovery set. The figure shows the number of significant genes identified at each step of the microarray analysis procedure with subsequent filtering steps for statistical significance and fold change expression differences. WT vs KO represents a joint comparison of all data, whereas WT vs GKO and KKO represent separated analyses. The numbers of genes falling through the analysis are shown separately for gene level and exon level summarization. The pie chart shows the grouping of molecular functions for the 198 gene set.