The understanding of the development and evolution of organs and organ systems is one of the major challenges in present day biology. The research in our laboratory is focused on two basic biological problems: how cells fuse to form giant multinucleate cells and how organs form in animals. In addition, we are studying how these two universal processes have changed during evolution. We are studying these processes in developing embryos and larvae of the nematode Caenorhabditis elegans. We will determine the precise physicochemical mechanism of developmental cell fusion events in an animal system and how this process is controlled in development.