Hedgehog signaling is required for many aspects of development in vertebrates and invertebrates. Misregulation of the Hedgehog pathway causes developmental abnormalities and has been implicated in certain types of cancer. Large-scale genetic screens in zebrafish have identified a group of mutations. termed you-class mutations. http://www.roneverhart.com/KNIPEX-7-1-4-in-88-01-180-Alligator-Water-Pump-Pliers/