Median mutational variance in gene expression

Value 4.7E-05 (Substitution/generation)^2
Organism Budding yeast Saccharomyces cerevisiae
Reference Landry CR, Lemos B, Rifkin SA, Dickinson WJ, Hartl DL. Genetic properties influencing the evolvability of gene expression. Science. 2007 Jul 6 317(5834):118-21PubMed ID17525304
Method Researchers performed a mutation-accumulation (MA) experiment (Fig. 1A) in S. cerevisiae in order to isolate the contribution of the mutational process to gene expression evolution.With serial transfer of random colonies, they accumulated spontaneous mutations by maintaining parallel lines with effective population sizes of ~10 individuals. The lines diverged from an isogenic common ancestor for 4000 generations. They estimated the Vm of gene expression for genes that showed significant statistical differences (Bayesian posterior probability > 0.99) in expression among any pair of the four MA lines by using logtransformed relative expression levels.
Comments The rate of phenotypic evolution due to mutation alone can be measured by the mutational variance (Vm), which is defined as the increase in the variance of a trait introduced by mutations each generation. It can be calculated from the variance of traits among MA (mutation accumulation) lines. For haploid asexual organisms, Vm = 2sb^2/t, where sb^2 is the between-line variance and t is the number of generations. See BNID 105091
Entered by Uri M
ID 105090