The Shaven (Sha) Mutation, Chromosome 15

The study investigated the Shaven (Sha) mutation in mice, which was first identified in the 1960s in Edinburgh, Scotland. Mice with this mutation exhibited hair growth between 28 and 34 days of age, characterized by short fuzzy hairs primarily on the head and anterior back, with cyclic regeneration and abnormal vibrissae. Genetic linkage studies on Chromosome 15 suggested that mutations like caracul, shaven, and velvet might result from altered hair keratin expression or structure. The mutation caused a greasy coat appearance due to abnormal lipid content, similar to the rough mouse mutation and "sticky" in guinea pigs. Histological skin abnormalities were noted to resemble those in the naked mouse mutation, and the Sha mutation was compared to other mouse mutations with alopecia in chemical carcinogen studies.