On the evolution of codon volatility.
Volatility of a codon is defined as the probability that a random point mutation in the codon generates a nonsynonymous change. It has been proposed that higher-than-expected mean codon volatility of a gene indicates that positive selection for nonsynonymous changes has acted on the gene in the recent past. I show that strong frequency-dependent selection (minority advantage) in large populations can increase codon volatility slightly, whereas directional positive selection has no effect on volatility. Factors unrelated to positive selection, such as expression-related or GC-content-related codon usage bias, also affect volatility. These and other considerations suggest that codon volatility has only limited utility for detecting positive selection at the DNA sequence level.
Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan 48109, USA. jianzhi@umich.edu
Jianzhi
J
Zhang
D000818:Animals; D001482:Base Composition; D005075:Biological Evolution; D003062:Codon / Q000235:genetics*; D020862:GC Rich Sequence; D005796:Genes / Q000235:genetics*; D016678:Genome; D006801:Humans; D009154:Mutation / Q000235:genetics*; D012641:Selection, Genetic
D003062:Codon