We all start as a single cell, which divides and eventually forms the body. A great deal of cell communication goes into making decisions about this body plan. My research examines how cells communicate with one another during embryonic development. The body plan is set up by organizing centres, or groups of cells that dictate signals to other parts of the early embryo. Two centres have been identified in mammals: the anterior visceral endoderm (AVE) coordinates the development of the head, and the node arranges the trunk into front, back, left and right. The way these organizing centres control growth of the embryo, and the cell-to-cell signalling involved in the process, are poorly understood. The same signalling systems used in creating an embryo break down during cancer. Ultimately, if we can identify what happens under normal circumstances, we can better understand what goes wrong with signalling pathways during the development of cancer or congenital defects. The results of my research also have implications for stem cell research. Stem cells have the potential to differentiate into various types of cells. If we can determine the signals that cause particular cells to become liver, brain or kidney cells during embryonic development, researchers should be able to cue stem cells to differentiate into specific cell types.