Dr. Barbara Wold is the Bren professor of molecular biology and director of the Beckman Institute at Caltech. A substantial biological challenge is to understand the regulation and execution of developmental decisions that lead from multipotential, undifferentiated precursor cells to their specialized differential products. In the Wold lab at the California Institute of Technology, we are interested in several interrelated aspects of this problem, and we also work to develop new methods for studying it. The particular cell lineage problem we study begins with the specification of mesoderm in early development and continues to the final differentiation of skeletal muscle or cardiac muscle in the fully developed animal. To study this process we use the mouse as our experimental system. Molecular-level analyses use cell culture model systems and transgenic mice. These projects include studies of in vitro and in vivo protein-DNA interactions and of factors that amplify or suppress expression activity. Computational approaches involve the development of algorithms for use in large-scale gene expression analysis and the construction of a simulator framework for regulation in muscle development.