What makes proteins evolve?

Dennis Wall
Computational Biology Initiative


The process of protein evolution can be caused by a combination of active and passive forces including genetic drift, adaptive selection, and structural canalization. Which force is most important for a given set of proteins can be difficult to determine, but important to discern in order to build more coherent models of molecular evolution. In an influential paper (cited below) Kimura and Ohta proposed that proteins which are dispensable to the organism will evolve more rapidly, simply because they have fewer residues constrained by function. An alternative claim, brought out much later (Pal et al), suggested that a protein's dispensability is a correlate of the rate at which that protein is expressed and that any relationship between protein evolutionary rate and expression will disappear when expression is factored out. In this theory lunch, I will shed some light on what principles may in fact be governing the rate of protein evolution, using functional genomic data from yeast.


M Kimura, T Ohta "On some principle governing protein evolution", PNAS 71:2848-2852 1974

C Pal, B Papp, L D Hurst, "Genomic function: Rate of evolution and gene dispensability", Nature 421:496-7 2003. PubMed