Gene expression noise refers to the stochastic variation in the expression level of a gene among isogenie cells under the same condition.Previous studies showed that the level of expression noise varies substantially among genes,is determined genetically,and is selectable.In this talk I address two questions on gene expression noise.First,I present evidence for adaptive elevation of expression noise in a group of plasma-membrane transporters in the budding yeast Saccharomyces cerevisiae and offer a mathematical model explaining why and when high noise may be beneficial.Second,using the flux balance model of metabolic networks,I estimate the deleterious effect of expression noise on the growth rate of yeast cells and show that gene expression noise lowers the maximal fitness as well as the efficacy of natural selection.Thus,expression noise is a two-edged sword that can be both advantageous and deleterious.
展开▼
