Post-duplication relaxation of purifying selection in paralogs. a – Schematic illustrating the rationale for the comparison of dN/dS for human-mouse orthologs versus human paralogs. dN/dS levels were averaged for sets of proteins, related as shown, where the human paralogs duplicated after the human-mouse divergence. b – Average dN/dS leves, with 95% confidence intervals (y-axis), is plotted for human-mouse orthologs (diamonds) and human paralogs (squares). A series of increasing cut-offs based on the level of dS (x-axis) between human paralogs was employed so that each set is restricted to more and more distantly related paralogs.
Jordan et al. BMC Evolutionary Biology 2004 4:22 doi:10.1186/1471-2148-4-22