What is the difference between dominant and recessive black genes?

The difference between dominant and recessive black genes comes down to their location in the dog’s DNA, how they are inherited, and whether they actually exist in the Great Dane breed.

Dominant Black (K 

B

 )

• Genetic Location: The dominant black gene is located on the K-locus (specifically the CBD103 gene). Before modern genetic discoveries, researchers initially thought dominant black was located on the A-series.

• Expression: Because it is the most dominant allele, a dog only needs to inherit one copy of the K 

B

  allele to have a solid base coat (which can be black, or modified to blue, chocolate, or lilac by other genes). This dominant gene acts as a “gatekeeper” that completely overrides the A-locus, preventing patterns like fawn or tan points from being visible.

• Presence in Danes: This dominant gene is responsible for the solid black coats commonly seen in Great Danes.

Recessive Black (a)

• Genetic Location: The recessive black gene is located on the A-locus (the ASIP gene), which typically controls the distribution of red/yellow and black pigments across the coat.

• Expression: Because it is a simple recessive trait, a dog must inherit two copies of the a allele (a homozygous a/a genotype) from its parents in order for the recessive black color to be visually expressed.

• Presence in Danes: The recessive black allele (a) is not present in Great Danes. Instead, it is found in other breeds, such as certain herding dogs.