Description:  The locus K has three alleles in the order of dominance: dominant black (KB)> brindle (kbr)> recessive yellow (ky). The phenotypic expression of the KB allele is inherited autosomal dominant. The resulting coat color is affected by the E and A loci. When eumelanin is expressed, the final coat color is black or brown (presence of wild type E allele). When pheomelanin is expressed, the final coat color is light, red-brown, red or brindle.

The second allele is kbr, also known as “brindle”. The KBr allele is probably due to a single mutation that still allows for the expression of the agouti gene but causes annealing of the agouti patterns that are due to the presence of alleles in the locus-A. The KBr allele is recessive to the KB allele and is also dominant over the third Ky allele.

The ky allele is a normal allele without mutation and has no effect on coat color. Allows full expression of the colors defined by locus A. If the dog is Ky/Ky in the K-locus, the dog’s coat color is determined by locus A. If the dog is KB/KB in the K-locus, the A-locus will be hidden and its color will be determined by the B and E loci.

Currently, the test for the “KBr” allele is not available, although its presence can be deduced through testing for the presence of the dominant black allele, as well as through parent and offspring phenotypes.

The assay does not exclude the presence of any unknown mutation in the CBD103 gene.


Inheritance: autosomal dominant


Mutation: c.67_69delGGA in CBD103 gene


Sample: EDTA whole blood (1.0 ml) or 2 buccal brushes. For official purposes, the confirmation of the dog’s identity by Veterinarian is recommended.


The analysis is suitable for the following breeds: KB is an important allele in the formation of black pigment in at least 50 breeds.