Four dominant autosomal mutations affecting skin and hair development in the mouse.

Four new dominant autosomal mutations influencing the development of skin and hair in the mouse were tested for allelism with each other and with hairless, hr. Three of the mutations probably constitute an allelic series and have been given the symbols Frl1, Frlb, and Frlc. The Frl series shows no evidence of linkage with hr. The fourth mutation, Hrn, is a dominant and homozygous viable allele at the hr locus. With the possible exception or Frlb, all mutants were of spontaneous origin. Because of their unique characteristics, these new mutants are of potential value as mouse model systems in studies of skin carcinogenesis and related areas of research.