Convergent Divergence: Jacque Monod’s "Necessity and Chance" in the Age of Epigenetics

Dr. Hong Qian

Professor

Department of Applied Mathematics, University of Washington, Seattle

Abstract

Single-molecule biophysics is one of the important recent developments in molecular biology. We now know that biochemical reactions are chancy events, and gene expressions inside a single living cell are stochastic. Following Jacque Monod’s idea of “Chance and Necessity”, we develop a quantitative (even mathematical – but don’t be discouraged!) description of cellular dynamics based on network of biochemical reactions in a single cell: We show that different epigenetic phenotypic states of a single cell are different “forms” of a same biochemical reaction system, just as different conformational states of a single enzyme molecule are different “forms” of a same polypeptide chain. There is an “evolutionary” process, with punctuated equilibria, gives rise to a sustainable diversity among individual cells in a homogeneous population. The emergent epigenetic states have natural robustness against both internal and external perturbations.

• Date : July 3 (Wednesday), 16:00-17:00pm

• Venue: New Biology Building RM143

• Host: Prof. Hongwei Wang