A missense mutation in the bovine MGF gene is associated with the roan phenotype in Belgian Blue and Shorthorn cattle

The Roan locus is responsible for the coat coloration of Belgian Blue and S horthorn cattle. The solid-colored and white animals are homozygotes, and t he roan animals, with intermingled colored and white hairs, an heterozygous . The roan phenotype was mapped to cattle Chromosome (Chr) 5 with microsate llites, and a candidate gene was proposed (Charlier et al. Mamm Genome 7, 1 38, 1996), PCR primers to the exons of this candidate gene, the steel locus or mast cell growth factor (MGF) were designed. Solid-colored and white an imals were sequenced. A missense mutation at 654 bp (amino acid 193, Ala -- > Asp) was detected in these two groups. A PCR-RFLP was designed to this si ngle base pair change, and 143 animals in total (Belgian Blue, Shorthorn, a nd various other breeds) were screened. In addition, the Canadian Beef Catt le Reference Herd (http://iskyway.usask.ca/similar to schmutz) was used to verify Mendelian inheritance of this marker with the phenotypic inheritance of roan. Our data suggest that this mutation in the bovine MGF gene is res ponsible for the roan phenotype.