The Chicken Frizzle Feather Is Due to an Alpha-Keratin (KRT75) Mutation That Causes a Defective Rachis

The study identified a mutation in the α-keratin gene KRT75 as the cause of the frizzle feather phenotype in chickens, characterized by a defective rachis and altered feather structure. This mutation involved a 69-bp in-frame deletion, leading to protein dysfunction and affecting keratin dimerization. The frizzle gene was transmitted in an autosomal incomplete dominant mode. Experimental approaches, including retroviral-mediated expression and misexpression studies, confirmed the mutation's impact on feather morphology, highlighting the role of α-keratins in feather development. The research suggested potential physiological effects of the mutation and emphasized the importance of genetic approaches in understanding feather morphology and evolution.