Clustering the samples based on their overall gene expression programs. A, Clustering based on all genes used in the analysis (1,100 random genes). B, Clustering based on the differentially expressed genes after averaging spots representing the same gene as listed in Tables I to IV. C, Average expression profiles of gene groups obtained by hierarchical clustering. Groups 1 to 5 are described in the text and Tables I to IV and contained 10, 13, 38, 33, and 10 genes, respectively.