Distribution of correlations and global network properties. (A) Distributions of correlation values. We see that Pearson correlations are bimodally distributed, with a peak at zero and otherwise a bell-shaped distribution centered at the right side of zero. The partial correlation corrects this and centers the distribution around zero, showing that spurious correlations occur as a result of genome expansions and contractions. The inset shows the distribution in log scale. (B) Clustering behavior for partial correlations (pcor) and sign score (sign)-based networks, where clusters are simply connected components of size ≥2. (C) Degree distributions for different thresholds. For the thresholds shown here, the best fit is given by a power law with exponential cutoff (see Supplementary material S6).