We are interested in identifying systems-level design principles of cellular differentiation circuits. We specialize in measuring the dynamics of gene regulatory circuits that control cellular differentiation at the single cell level. Using quantitative fluorescence time-lapse microscopy, we can directly observe the activities of multiple circuit components simultaneously in individual cells. The resulting data provides quantitative insights into the dynamics of circuit component interactions that can be analyzed in terms of mathematical models to uncover systems-level design principles. We are also interested in identifying evolutionary pressures that select for specific circuit architectures and dynamics.