ABSTRACT
Caracul, a dominant mutation, arose as a single individual in a litter of seven in a stock of Swiss mice. Directional caracul heterozygotes resemble caracul heterozygotes except for a ridge of hair extending down the dorsal midline that disappears at weaning. Directional caracul homozygotes have very curly truncal hair and develop bald spots over the upper back that persists through life. The caracul mutation on this background was held at the Jackson Laboratory prior to 1947. Genetic linkage studies of hair keratin genes and the mutations caracul, shaven, and velvet on Chromosome 15 suggested that these mutations may be due to altered hair keratin expression or structure. In 1971, the caracul mutation in the caracul, hammertoe, steel linkage testing stock was replaced by a point mutation, caracul, that occurred on the C57BL/6J inbred background in 1963.
