Oct. 24-26, 2009, Yingjie Overseas Exchange Center, Peking University, Beijing, China中文版

Gene Expression Noise and Evolution

Jianzhi Zhang

University of Michigan, USA

Abstract

Gene expression noise refers to the stochastic variation in the expression level of a gene among isogenic 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.

Jianzhi Zhang

University of Michigan, USA

Biography

Jianzhi Zhang is Professor of Ecology and Evolutionary Biology at the University of Michigan, Ann Arbor, Michigan, USA. He has a wide array of research interests in molecular and genomic evolution, including molecular basis of adaptation, evolution of duplicate genes, genetic basis of human origins, vertebrate sensory gene evolution, and evolutionary systems biology. His researches combine theoretical modeling, empirical data analysis, and experimental molecular biology. He has published over 100 research articles, reviews, and commentaries. Zhang obtained B.S. from Fudan University in 1992 and PhD from Pennsylvania State University in 1998, both in genetics. He is the current Secretary of the Society for Molecular Biology and Evolution, and serves on the editorial boards of six journals, including PLoS Genetics, Genome Biology and Evolution, and Gene.