Presence of the dominant extension allele E-D in red and mosaic cattle

The melanocyte-stimulating hormone receptor (MC1-R) is a central regulator of mammalian coat colour, encoded by the extension locus. In cattle, the do minant extension allele ED is associated with the production of black pigme nt in coloured areas. Genotyping of the MC1-R gene in a bull with mosaic ex pression of red vs. black pigment verified the existence of the E-D allele, in spite of the fact that the majority of the animal is red coloured. No f urther mutations were found within the ED variant of the MC1-R gene, which was inherited from a completely red mother (genotype E-D/e).