The vertebrate limb is a classical model for understanding patterning of three-dimensional structures during embryonic development. Although decades of research have elucidated the tissue and molecular interactions within the limb bud required for patterning and morphogenesis of the limb, the cellular and molecular events that shape the limb bud itself have remained largely unknown.
Department of Genetics, Harvard Medical School, and Center for Systems Biology, Massachusetts General Hospital, 77 Avenue Louis Pasteur, Boston, MA 02115, USA.
