The shape of an organism largely depends on movements of epithelial sheets during embryogenesis. The discovery of a second MAPK kinase in Drosophila provides new insights into mechanisms that control the coordinated movement of epithelial cells.

A left-right asymmetry in neuronal function is specified surprisingly early during embryogenesis in Caenorhabditis elegans. Do early cues influence left-right asymmetries in other animals? How are early cues remembered until late in development?