Keratins are the structural proteins of skin, hair, nails, feathers, and scales. There are 54 described  keratins in humans, a subset of which has also been found in the green anole genome. Distinct combinations of keratins in skin appendages are what give these tissues their unique properties such as flexibility, rigidity, or cornification (i.e., the process of forming an epithelial barrier). Leer más.