ABSTRACT
The fuzzy (fz) mutation arose spontaneously in 1945 in the CFW stock of F. G. Carnochan at the Carworth Farms. Double mutants have been produced by crossing fuzzy with crinkled. Since crinkled mice only have awl hairs and it was initially thought that the fuzzy mice only had zigzag hairs, the double mutants were expected to have no hairs, which turned out not to be the case. Mice homozygous for the fuzzy mutation (fz/fz) can be identified by 6 days of age by the presence of abnormal vibrissae and unevenness of the truncal coat. The dermal papilla of fz/fz mice is short and abnormal during the stage of hair shaft proliferation (anagen), which may be responsible for the failure of the hair to develop normally. The fuzzy mutation affects the ability of the epidermis to produce normal hair in response to dermal influences. Morphological abnormalities in the dermal papilla suggest that the biochemical abnormality lies in this region.
