Inheritance of Hair Constrictions in Mice

The frequencies of multi-constricted hairs in the pelage is the same (75%) in the caudal mid-dorsum of C57BL/10 and CBA inbred mice, but there are more single-constricted hairs in C57BL mice (9.41%) than in CBA mice (0.13%). This structural feature is used as a basis for genetic analysis of the hair coat.-The frequency of single-constricted hairs (4.41%) in F(1) mice is intermediate between the frequencies observed in the CBA and C57BL parent strains. Data from the F(2) crosses and backcrosses to the respective parent strains indicate that the presence of numerous single-constricted hairs in the pelage is an inherited characteristic. The mode of inheritance is controlled primarily by a semi-dominant autosomal gene (single-constriction; Hct), without the involvement of maternal factors.