This webpage is part of a series on Dog Coat Color Genetics and was last updated on July 1, 2006 by Sheila Schmutz

  • Black versus Red
  • Brown
  • DNA Diagnostic Services
  • Black versus Red

    Black, or black and white is a very common coat color in many dog breeds. Red is the classic color associated with the Irish Setter. However red also occurs in many other dog breeds in paler shades ranging through red to orange and yellow. It would appear that most of the hunting dogs that have black variants, such as German Shorthairs, German Wirehairs, and Pudelpointers are black because they have an E alllele at the MC1r gene. The Large Munsterlander is "always" E/E and black. However the Amreican Brittany and the Irish Setter are always e/e and red or orange or yellow. But the Small Munsterlander and German Longhair are brown, not red, and are also E/E due to the interaction of another gene B, explained below.

    The gene causing red/black is the Melanocyte Stimulating Hormone Receptor Gene (MSHr), also called the Melanocortin Receptor 1 gene (MC1R). This gene has two common alleles E and e. When E is present in a dog, it has some black or brown in its coat because of the production of eumelanin. This is the dominant allele in the series. Dogs that are e/e are red or yellow due to phaeomelanin production, and this is the recessive genotype.

    These 2 Dachshunds exemplify the two genotypes at this locus. The red dog has a black nose but is a clear red and has the genotype e/e at MC1R. The black is a black-and-tan and has an E allele, however his black-and-tan pattern is due an agouti allele (at)(see the agouti page for more details).

    There is a third allele at the E locus, E which is discussed on the page about Melanistic Mask. Melanistic masks do not occur in the hunting breeds.

    There are Dachshunds, such as the one shown, and dogs of other breeds that have red hairs with darker or black tips on them. These dogs do not have an e/e genotype. This non-solid red is caused by an allele at the agouti locus, ay. Other breeds such as Chows also fall into the category of not being red because of an e/e genotype. The colors tan or fawn, typically associated with agouti, are not always that easily distinguishable from the red of an Irish Setter. Depending on the breed, one red or the other is more common and in most breeds only one or the other red occurs.

    In some breeds, such as Labrador Retrievers the dogs are more yellow than red. The shade varies as is illustrated by the two littermates above whose parents were also both yellow.

    The MC1R gene has been mapped to dog chromosome 5.

    Little did not include the Hungarian Vizsla in his studies. They are hunting dogs which are typically gold to red and typically have brown noses because they are also homozygous for the recessive brown allele/s at the B locus. (see Brown for further details)

    This very white coat color is desirable in English Setters but it makes it difficult to tell what color the pigmented part of her coat is. By MC1r testing, she is e/e and therefore red.

    Breeds in which yellow-to-red dogs of the "e/e" genotype have been detected

    Note that in some breeds dogs with an e/e genotype are more often cream to white than yellow to red (see page on white for a discussion of these breeds).

  • Newton, J., A. Wilkie, L. He, S. Jordan, D. Metallinos, N. Holmes, I. Jackson and G. Barsh. 2000. Melanocortin 1 receptor variation in the domestic dog. Mamm. Genome 11:24-30.
  • Everts, RE, Rothuizen,J. and van Oost,B.A. 2000. Identification of a premature stop codon in the melanocyte-stimulating hormone receptor gene (MC1R) in Labrador and Golden retrievers with yellow coat colour. Anim. Genet. 31: 194-199.
  • Schmutz, S.M., J. S. Moker, T. G. Berryere, and K. M. Christison. 2001. A SNP is used to map MC1r on dog chromosome 5. Animal Genetics 32:43-44.
  • Thomas, R., M. Breen, P. Deloukas, N. G. Holmes and M. M. Binns. 2001. An integrated cytogenetic, radiation-hybrid and comparative map of dog Chromosome 5. Mamm. Genome 12:371-3100.
  • Brown

    The two dogs at the left are representatives of the two possible color phases of the Large Munsterlander. Most Large Munsterlanders are black and white but occasionally a brown and white one is born. All Small Munsterlanders are brown and white.

    The reason that the German Longhair, who is E/E, is always brown or brown and white and the Large Munsterlander, who is also E/E is usually black and white, is due to another gene - B (for brown and black from Little's labelling) or Tyrosinase Related Protein 1. There are actually 3 common mutations and perhaps additional rare ones that occur in this gene which result in brown instead of black eumelanin production. The black allele B is dominant to the brown alleles (bS,S, bc). The nose leather, pads, and eye rims are also affected by this gene. They are black if a B allele is present but brown if not.

    In dogs which are yellow to red (e/e at MC1r), TYRP1 mutations affect the nose and pad coloration, changing it from black to brown. The yellow lab puppies, above, both have black noses but the Vizslas have brown or flesh colored noses.

    All dogs which have brown coat color have at least one E or Em allele so that eumelanin is produced. The German Longhair, at the left, is homozygous for one of the common mutations. Her genotype is bdbd. The Large Munsterlander, above, is homozygous for the other with a genotype of bsbs. The Newfoundland, at the right, is homozygous for the rarer brown mutation. His genotype is E/E, bc/bc. Dogs which are heterozygotes of any combination of these mutations would also be brown, i.e. bs/bd

    .

    Breeds in which brown dogs of with TYRP1 DNA changes have been detected

    The list of alleles may not be complete because relatively few dogs have been tested for some breeds