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 dominant extension allele E(D) is associated with the production of black pigment in coloured areas. Genotyping of the MC1-R gene in a bull with mosaic expression 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 further mutations were found within the E(D) variant of the MC1-R gene, which was inherited from a completely red mother (genotype E(D)/e).