Nucleotide Sequence of Endothelin-B receptor Gene Reveals Origin of Piebald Mutation in Laboratory Mouse

Piebald (Ednrb^s) is a coat color mutation of laboratory mice caused by a decreased expression of endothelin-B receptor gene (Ednrb). The IITES and JF1 mouse strains, whose origins are believed to be different from those of the common laboratory inbred strains, also show a phenotype similar to Ednrb^s. In the present study, we found that the nucleotide sequence of the Ednrb gene of the IITES and JF1 mice is identical to that of the Ednrb^s allele, Ednrb^s allele has an RFLP of the Ednrb gene identical with that of M. m. molossinus but different from other subspecies, and at least particular regions of chromosome 14 proximal to the Ednrb locus of the IITES and JF1 strains are derived from M. m. molossinus. These findings clearly indicate that the Ednrb^s allele of the laboratory mice has its origin in M. m. molossinus.