The Shaven (Sha) Mutation, Chromosome 15

The study investigated the Shaven (Sha) mutation in mice, which affected hair growth and was linked to Chromosome 15. Hair growth in affected mice began between 28 and 34 days of age, resulting in short fuzzy hairs primarily on the head and anterior back, with cyclic regeneration and abnormal vibrissae. The mutation was associated with altered hair keratin expression or structure, leading to a greasy coat appearance due to abnormal lipid content, similar to other mutations like rough (ro) in mice and "sticky" in guinea pigs. Histological skin abnormalities resembled those in the naked (N) mouse mutation, and the Sha mutation was compared to other mouse mutations with alopecia used in chemical carcinogen studies.