Comparison of correlation and mutual information based co-expression measures in 8 empirical data sets. Absolute value of bicor versus AMI,UniversalVersion 2for all probe pairs in each data set. The Spearman correlation and corresponding p-value between the two measures are shown at the top. The two measures show different levels of monotonic relationships in data sets. The red curve predicts AMI,UniversalVersion 2from bicor based on Eq. 18. The blue circle highlights the probe pair with the highest AMI,UniversalVersion 2z-score among those with insignificant bicor z-scores (less than 1. 9 ); the red circle highlights the probe pair with the highest bicor z-score among those with insignificant AMI,UniversalVersion 2z-scores (less than 1. 9 ).