UC Davis School of Veterinary Medicine Veterinary Genetics Laboratory
Dog Coat Color Dominant Black Test

Dominant Black (K Locus)

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The wide variety of coat colors in mammals is achieved by the production of two pigments, eumelanin (black) and pheomelanin (red or yellow). In most mammals, the switching between these 2 pigments is controlled by MC1R and Agouti genes. In dogs, original coat color research of pedigrees suggested that a third gene, named Dominant Black (K locus), was involved. This gene produces dominant black vs. brindle vs. fawn colors in breeds such as Great Danes, Pugs and Greyhounds among others.  Researchers recently have discovered that dominant black is due to a mutation in a Beta-defensin gene (CBD103).

The Veterinary Genetics Laboratory offers a test that can assist owners of black dogs to determine if their dogs are homozygous for dominant black or if they carry brindle or fawn.

Results are reported as:

K/K 2 copies of dominant black are present.
K/N 1 copy of dominant black is present.*
N/N Dog does not have the dominant black mutation.

* This result is sometimes associated with the brindle pattern.


Candille Sophie I, C B Kaelin  et al. A beta-defensin mutation causes black coat color in domestic dogs. Science 318, 1418 (2007) DOI: 10.1126/science.1147880

Veterinary Genetics Laboratory, Tel 530-752-2211, Email VGL