SHH, Species: Human

Sonic hedgehog (SHH) is a member of a small group of hedgehog secreted proteins that are essential for development in both vertebrates and invertebrates. There are three mammalian hedgehog homologues, sonic, desert, and indian, that signal via the Patched-1 and Patched-2 receptors. SHH is a morphogen that is essential during vertebrate organogenesis and adult stem cell division.