Cell movements during vertebrate development: integrated tissue behaviour versus individual cell migration

Cell migration during development is fundamental to the establishment of th e embryonic architecture. Depending on the context, cells may move either a s integrated sheets of tissue or individually. Recently, molecules that are involved in both these types of cell behaviour have been identified, helpi ng us to understand developmental processes as important as gastrulation an d neural crest formation, and ultimately, the morphogenetic movements that shape the embryo.