Recent work has shown that expression level is the main predictor of a
gene’s evolutionary rate, and that more highly expressed genes evolve
slower. A possible explanation for this observation is selection for proteins
which fold properly despite mistranslation, in short selection for
translational robustness. Translational robustness leads to the somewhat
paradoxical prediction that highly expressed genes are extremely tolerant to
missense substitutions but nevertheless evolve very slowly. Here, we study a
simple theoretical model of translational robustness that allows us to gain
analytic insight into how this paradoxical behavior arises.Comment: 32 pages, 4 figures, Genetics in pres