k -means clustering of expression profiles with assigned GO terms. Thirteen gene clusters determined by k-means clustering are depicted with corresponding, significantly enriched GO terms  (see also Figure 4). Over- and underrepresented GO terms are indicated by red and green symbols, respectively. Black lines mark genes with a baySeq  likelihood value >0.99, which indicates differential expression; all other genes are colored in grey. All values are depicted by Z-score transformed NPKM values (y-axis) versus sampling points I to V (x-axis).