The effect of multifunctionality on the rate of evolution in yeast.

Multifunctional genes are expected to evolve at lower rates because mutations in such genes that improve one function might often have deleterious effects on other functions. Here we tested for an association between multifunctionality and evolutionary rates in genes of Saccharomyces cerevisiae, and we find a highly significant negative correlation between the number of biological processes in which a gene is involved in and its rate of evolution. However, the magnitude of this effect is small, and the results do not support the notion that multifunctionality limits a gene's rate of evolution.