The Dominant Black gene (K Locus) affects pigment switching between eumelanin (black) and phaeomelanin (red or yellow) by interacting with the Agouti and MC1R genes.
Phenotype: Dogs with the Dominant Black variant display solid coat coloration in fully pigmented areas or, in some cases, display a brindle pattern.
Mode of Inheritance:Autosomal dominant
Alleles: N = No Dominant Black, K = Dominant Black
Breeds appropriate for testing: Many breeds
Explanation of Results:
Dogs with N/N genotype are expected to be able to express the Agouti gene. They may display black pigment in their coats, but they can also exhibit a variety of other colors and markings including those produced by hairs with alternating bands of color (Agouti). They cannot transmit this dominant black variant to any of their offspring.
Dogs with N/K genotype are expected to be unable to express the Agouti gene or exhibit reduced Agouti expression. Dogs with this genotype are sometimes brindle. If not brindle, they are expected to display solid eumelanin pigmentation (no pigment banding in the hair shaft) in colored areas on the body. Overall appearance is also determined by genotype at MC1R (E Locus), Brown (B Locus), merle, and other loci. N/K genotype dogs will transmit this dominant black variant to 50% of their offspring.
Dogs with K/K genotype are expected to be unable to express the Agouti gene, leading to solid eumelanin pigmentation (no pigment banding in the hair shaft) in colored areas on the dog's body. Their overall appearance is also determined by genotype at MC1R (E Locus), Brown (B Locus), merle, and other genes. These K/K dogs will transmit this dominant black variant to all of their offspring.
$45 one test per animal
$65 two tests for coat color/fur type/bobtail (same animal) (excludes Cocoa)
$85 three tests for coat color/fur type/bobtail (same animal) (excludes Cocoa)
+ $15 each additional test if ordering more than three coat color/fur type/bobtail tests on the same animal (excludes Cocoa)
$115 per animal
Additional coat colors $15 per test (excludes Cocoa)
The wide variety of coat colors in mammals is achieved by the production of two pigments, eumelanin (black) and phaeomelanin (red or yellow). In most mammals, the switching between these two pigments is controlled by MC1R and Agoutigenes. 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).
Testing for Dominant Black can assist owners of black dogs to determine if their dogs are homozygous for dominant black or if they carry brindle or fawn.