Testing the different lists of protein-protein interactions and evolutionary rates from the two studies. (a) A significant correlation is found when using evolutionary rates of orthologs from Jordan et al.  with our list of protein-protein interactions. Several outliers are not shown but were included in the analysis. (b) No correlation is seen when using our evolutionary rates of orthologs with Jordan et al.'s list of protein-protein interactions.
Fraser et al. BMC Evolutionary Biology 2003 3:11 doi:10.1186/1471-2148-3-11