Dr. van Haeringen Laboratorium B.V.

H819 Coat Colour K-locus


During the last decades, a large number of scientific publications have described the genetic principles of coat colour and coat variation. Coat colours and coat variations are influenced by many hereditary factors. The DNA-tests are based on physiological effects in the body, in which the production and distribution of pigments result in many coat colour variants. In several cases, the coat colour of an animal may only be decided using DNA-tests.

The Beta-defensin gene (CBD103 gene) produces dominant black vs. brindle vs. fawn coat colours. This gene is also known as the K-locus or Dominant black gene. The coat colour is further complicated by the interaction with the E-locus and the A-locus (agouti). The Coat Colour K-Locus (H819) tests for the genetic status of the K-Locus. The K-locus has three variants (alleles). The allele KB is dominant over the alleles kbr and ky; allele kbr is dominant over allele ky. The dominant allele KB, also called dominant black allele, does not allow the agouti gene to be expressed. A dog with at least one copy of the KB allele expresses a base colour, which is determined by the B- and E-Locus. The allele kbr results in brindling and allows the agouti to be expressed but causes brindling of the agouti patterns. The A-Locus (agouti) represents several different colours, such as fawn/sable, wild sable, tan points and recessive black. The allele ky allows the agouti to be expressed without brindling. When a dog has two copies of the ky allele (homozygous ky/ky) the agouti locus determines the dog’s coat colour. The test does not discriminate between the alleles kbr and ky.

Test specific information

Since 2015, two brands have been developed. CombiGen® is mainly directed at veterinarian applications, whereas CombiBreed® is mainly directed at breeders and/or owners.
Detailed information about Coat Colours and Coat Variation is presented at www.combibreed.com.


Most coat colours and coat types are usually visible directly after birth.

Turn Around Time

The turn-around-time of a test depends to a large extent on the logistics of sample transportation to the laboratory. After receiving the sample at the test location, you can normally expect the result within 10 working days. A longer delivery time applies to tests carried out by a Partner Lab.

Location of disease or trait

Genetic factors influencing coat colours and coat types are usually visible on the outside of an individual. Several factors may be hidden by the external variation.

Breed dependence

For this test samples from all breeds are accepted.

Sample type

For this DNA test we accept the following materials: Blood EDTA, Blood Heparin, Swab, Semen, Tissue. Please contact Dr. Van Haeringen Laboratorium if you wish to submit other material as listed.


Coat colours and coat types are based on many genetic factors. For each factor, a separate test result will be returned.


Various genetic factors influencing coat colour and coat types are inherited in a dominant or recessive mode. Coat colours are influenced by a large number of genetic factors.

Severity of Disease


Code H819

Coat Colour K-locus

€ 47,80 (Incl. 21% VAT)
€ 39,50 (Excl. VAT)