NEWS AND VIEWS Modularizing gene regulation

As our ability to tinker with cellular components increases, the possibility of designing and controlling the functioning of living systems seems closer than ever. In the pioneering monograph ‘What is life?’, Erwin Schrödinger pointed out the now obvious fact that living organisms obey the well-established laws of physics (Schrö-dinger, 1945). Yet, there is a long way from the atomic interactions at the molecular level to the behavior of even the simplest bacterium. So far, the type of predictive behavior that has been so successful in physics, chemistry, and engineering is largely missing in biology. Biological systems are not static; they evolve and adapt, grow and die. They are also intrinsically stochastic and live in a fluctuating environment. All these contingencies make quite a challenging task to apply the well-established principles of engineering to biology