Principal component analysis and hierarchical clustering (A) RNA-seq data. Principal Component 1 (PC1, x-axis) represents 31.4% and PC2 (y-axis) represents 22.1% of total variation in the data. Hierarchical cluster of 9 samples with heatmap representing all 9 PCs in left-to-right order. (B). Exon array data. PC1 vs. PC2 on Exon array data together representing 33.2% and 21.8% of the data variability. Hierarchical clustering shows similarities to that in A, e.g. sample C4 departs strongly from remaining data, samples C3, C5 appear to be neighbors in both data sets.