We study the cis-regulatory mechanisms that drive differential patterning in embryos and other tissues. We are interested in questions such as how do transcription factors act in combination at cis-regulatory modules to support patterns of expression? Or how do cis-regulatory modules located on non-contiguous stretches of DNA coordinate their temporal action? Also, we are interested in how patterning of distinct cell types in the embryo controls cells' behaviors. Developmental biologists use many different approaches to understand how cells acquire their identities and how this influences their roles within the animal. We use the Drosophila model system to provide insights into cell patterning and cell migration, because it is a great system with a long-standing history that allows us to use a variety of approaches to provide rigorous answers to our questions: genetics, biochemistry, live in vivo imaging, and quantitative analysis.