Evolution of molecular error rates and the consequences for evolvability

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 108; no. 3; pp. 1082 - 1087
• Main Authors: Rajon, Etienne, Masel, Joanna, Lindquist, Susan
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 18.01.2011; National Acad Sciences
• Subjects: Alternative Splicing - genetics; Biological Sciences; Biological variation; Computer Simulation; Error rates; Evolution; Evolution, Molecular; Evolutionary genetics; Genes; Genetic diversity; Genetic loci; Genetic mutation; Genetic Variation; Genetics; Genotype & phenotype; Genotypes; Life Sciences; Models, Genetic; Molecules; phenotype; Population Density; Population dynamics; Population mean; Population size; Populations and Evolution; Protein Biosynthesis - genetics; protein folding; Proteins; Selection, Genetic; Stop codon
• ISSN: 0027-8424; 1091-6490; 1091-6490
• DOI: 10.1073/pnas.1012918108

Making genes into gene products is subject to predictable errors, each with a phenotypic effect that depends on a normally cryptic sequence. Many cryptic sequences have strongly deleterious effects, for example when they cause protein misfolding. Strongly deleterious effects can be avoided globally by avoiding making errors (e.g., via proofreading machinery) or locally by ensuring that each error has a relatively benign effect. The local solution requires powerful selection acting on every cryptic site and so evolves only in large populations. Small populations with less effective selection evolve global solutions. Here we show that for a large range of realistic intermediate population sizes, the evolutionary dynamics are bistable and either solution may result. The local solution facilitates the genetic assimilation of cryptic genetic variation and therefore substantially increases evolvability.