The Pearson correlation coefficient and the mutual information for all pairwise comparisons of genes for two large-scale gene expression datasets are shown (black points) overlayed by the same measures obtained from shuffled data (blue points). The expected mutual information calculated from Eq. (14) is shown as read curve. For the first dataset (left) genes containing undefined values were omitted resulting in 5345 genes measured under 300 experimental conditions . For the second dataset (right) containing 22608 genes measured under 102 experimental conditions , a representative fraction is shown.