The identified probesets with P < 0.05 were hierarchically clustered based on their expression profiles under the effects of the four factors. One hundred and seventeen genes with differentially expressed profiles under the effect of at least one factor were used in this analysis. The logarithmic values of the ratios of two levels in each factor are indicated by different colors. Green and red color stands for up- and down-regulation, respectively. Black encodes no signifcant changes. (A) Hierarchical average linkage clustering. Ten clusters have been created with each of them labeled on the side of the heatmap. (B) The ten clusters represent the genes with the expressions induced by the change of the four factors.