Researchers observed in zebrafish and fruit fly embryos how cancer-related mutations in the RAS pathway -- a biochemical system cells use to transmit information from their exterior to their interior -- caused severe deformations. Fruit-fly embryos (above) showed how signals at the early stage of development (red in top photo) activate genes (purple in middle photo) and pattern structures in the fly larva (bottom photo.) Credit: (Photo courtesy of Stanislav Shvartsman, Department of Chemical and Biological Engineering