20 November 2015
Johan Paulsson
Department of Systems Biology
Harvard Medical School
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 are often 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. I will present mathematical frameworks that exploit natural fluctuations to more rigorously analyze data and to make predictions about what complex biological networks cannot do. I will also discuss some recent experimental results on how cells exploit fluctuations for control, e.g. in the design of synthetic genetic networks, bacterial cell fate decisions, and the connection between stochastic gene expression and DNA repair.