Organization of data by multivariate analysis. (A) and (C) correspond to female; (B) and (D) correspond to male. (A) and (B) – principle component analysis score plots. PCA has been performed on a correlation matrix, each spot represents a gel. (C) and (D) – hierarchical clustering dendrogram with single linkage and Euclidean distance. The spots that participated in both types of multivariate analysis were present in 100% of the 2-DE maps and passed the filter of the one-way ANOVA (p < 0.05) statistical test.