Figure 2

Multivariate Analysis and Principal Component Analysis (PCA) of experimental samples and groups. (a) The figure shows hierarchical clustering on the 150 genes showing the greatest inter-group variance among expressed genes in mice at 1 month of age (left panel) or in female mice only (right panel). (b) PCA based on the expression values of the 17,200 genes detected in the experimental samples (detection P value < 0.01 in at least one sample of an analysed series). A bi-dimensional visualization of the first two principal components is shown (PC1 accounted for 35.2% and PC2 for 25% of the variance among samples).