Keratins are structural proteins in skin, hair, and fingernails. one gene, called krt10, is located on the 17th chromosome in humans. it produces a keratin molecule that strengthens skin cells. researchers have identified several mutations that can lead to rough, damaged, blistering skin because the keratins are not as strong as normal. each of the identified mutations changes a specific amino acid at a particular location in the protein, and so is an example of a(n) mutation.