Abstract

All intracellular processes involve components present in low numbers, creating spontaneous fluctuations that in turn can enslave the components present in high numbers. The mechanisms often appear complex, with reaction rates that depend nonlinearly on concentrations, indirect feedback loops, and distributed delays. Most systems are also sparsely characterized, with a few steps known in detail but many important interactions not even identified. In the first half of the talk, I will discuss mathematical approaches that exploit natural fluctuations to more reliably analyze data and to make predictions about what complex biological networks cannot do. In the second half I will discuss some of our recent experimental results on the role of fluctuations in cells, e.g. in the segregation of mitochondria, oscillations of synthetic genetic networks, bacterial cell fate decisions, and DNA repair.