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.
A horse that inherits a Grey coat colour can be born in any colour. The grey gene causes progressive depigmentation (fading) of the hair and is considered to be the “strongest” of all coat colour modifying genes. The depigmentation process may last for years, but once the hair is depigmented, the original colour will never return. Some grey horses become completely white whereas others will keep tiny non-faded spots (also called fleabites). A horse can also carry mutations for other modifying genes which can further affect its coat colour.
The Coat Colour Grey test (P807) tests for the genetic status of the STX17 gene. This gene has two variants (alleles). The dominant allele G results in the Grey coat colour and the recessive allele N does not have an effect on the basic colour. The dominant allele G has a duplication of a part of the DNA. The test does not discriminate between horses carrying 1 or 2 copies of the duplication (N/G or G/G). All horses carrying the duplication will turn grey.
Test specific information
This test is also included in a Combination Package Coat Colour.
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.
The Turnaround Time (TAT) depends on various factors, such as the shipment time of your sample to the test location, the test method(s) and whether the tests are performed completely or partially by a Partner Lab or Patent owner.
The TAT of tests performed at our facilities is normally 10 working days after receipt of the sample at the testing laboratory (VHL, VHP or Certagen). For tests performed by a Partner Laboratory (so-called "partner lab test") or patent owner, the TAT is at least 20 working days after receipt of your sample. Because the shipment time to our Partner Labs or patent owner may vary due to factors we cannot influence, the mentioned 20 working days are therefore an estimate.
Sometimes it is necessary to re-run your sample. We call this a retest. In that case, the TAT will of course be extended.
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.
For this test samples from all breeds are accepted.
For this DNA test we accept the following materials: Hair, Semen, Blood EDTA, Blood Heparin, Tissue. Please contact Dr. Van Haeringen Laboratorium if you wish to submit other material as listed.
Coat colours are based on many genetic factors. For each factor, a separate test result will be returned.
This genetic factor is inherited in an autosomal, dominant, mode. This means, that the individual can be free of the mutation (homozygote normal), affected (homozygous affected) or carrier (heterozygous affected). Both carriers and affected individuals will show symptoms of the mutation.
Severity of Disease