Correlation between pairs of probe sets. A. Histograms of the Fisher transformed Pearson correlation values (Z score) of related (red) and not related (blue) pairs of probe sets in the four datasets examined. Only informative pairs (see methods) are shown. B. Scatter plot showing the Fisher transformed Pearson correlation values of all the pairs in two datasets. C. Comparison between the correlation values obtained in all four datasets. The color in the intersection between two datasets depicts the correlation values. The correlation disappears in shuffled data.