In order for vertebrate embryos to develop their body axes, they require what is known as an embryonic signaling center. This group of cells provides the instructions that determine where up and down, left and right, and front and back are. Biologists at Friedrich Schiller University Jena have now discovered that even cnidarians—which form the sister group to all other multicellular animals, according to current understanding—possess this fundamental coordinate system. The study is published in the journal Nature.