Coat colour genes in diversity studies

In this paper we describe the use of polymorphic genes affecting coat colou r as a tool in diversity studies of domestic animals. Although phenotypic d ata has been the main criteria for establishing different breeds, calculati on of genetic distances between breeds is normally performed using noncodin g microsatellite markers. As anticipated, MC1-R (melanocyte stimulating hor mone receptor) allele frequencies vary greatly between cattle breeds expres sing different coat colours. In multicoloured breeds, like Icelandic cattle , a high frequency of the E+ allele appears to be essential for colour vari ation. Whereas black breeds have a high frequency of the dominant acting al lele ED, entirely red breeds have no ED. Animals being homozygous for the d efective allele e occurred frequently in some cattle breeds, indicating tha t the MC1-R does not have crucial impact on animal physiology other than co at colour. The Et and e alleles were observed in the closely related river buffalo as well. None of the breeds included in this study express the roan phenotype. Consequently, they were monomorphic at the MGF locus. As for th e MC1-R locus, a correlation to colour pattern was observed for two c-kit a lleles as well, confirming that selection of specific phenotypes strongly a ffect the allelic variation of underlying loci. Information on genes affect ing the phenotype is therefore well suited for describing different breeds of livestock and, consequently, a practical tool in breed conservation.