Fig. 4
Effects of number of interactions and gene expression on strength of coevolution. The relationship of a the mean degree (average number of interactions between a protein pair) and b mean ancestral gene expression estimate with the phylogenetically-corrected correlation ρC for the binding group. Both protein pair metrics are weakly, but significantly correlated with the phylogenetically-corrected correlation ρC: weighted Spearman rank correlation ρS=0.26 (p<10−16) for mean degree and ρS=−0.09 (p=0.00131) for mean ancestral gene expression. This suggests both metrics are poor predictors of the strength of coevolution of gene expression between protein pairs