Wavy coat (Krt27Re-wc) resembles rex (Krt27Re) except that its effects are more severe. Waviness of the juvenile coat is visible a little earlier, and the adult coat appears rougher. Morphology of individual hairs and hair development are also affected in the same order of severity.
The mutation wavy coat, a dominant allele at the rex (Krt27Re) location, arose in 1968 in a chronic neutron irradiation experiment using an unspecified genetic background. It was imported to the Jackson Laboratory from Dr. Mary Lyon at Harwell in 1989. It was outcrossed once to a C57BL/6J female and then sibling mated. Embryos were cryopreserved in 1990 from matings of wavy coated homozygous males at N1F2 to C57BL/6J females.