Histogram of the rate of (A) protein evolution and (B) regulatory evolution in orthologs between C. elegans and C. briggsae vs. paralogs within C. elegans and C. briggsae. Both protein (d_N) and regulatory evolution (d_SM) are accelerated in paralogs compared to orthologs for the same amount of synonymous divergence. (C) Histogram of protein vs. regulatory evolution in orthologs and paralogs. For the same amount of regulatory divergence, paralogs have an accelerated rate of protein evolution compared to orthologs.