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 Silver dilution gene dilutes the black pigment but has no effect on the red pigment. The effect of the Silver dilution gene can vary greatly. The mane and tail are lightened to flaxen or silver gray, and may darken on some horses as they age. A black horse will be diluted to chocolate with a lightened mane and tail. A Bay horse with Silver dilution will usually have a lightened mane and tail, as well as lightened lower legs (places with black pigment). A horse can also carry mutations for other modifying genes which can further affect its coat colour.
The Coat Colour Silver dilution test (P784) tests for the genetic status of the PMEL17 gene. This gene has two variants (alleles). The dominant allele Z results in the dilution and the recessive allele N does not have an effect on the basic colour.
The same mutation responsible for the coat color Silver is also associated with Multiple Congenital Ocular Anomalies (MCOA) Syndrome, a wide range of ocular defects that occur in the anterior and posterior parts of the eye. The severity of the syndrome is dose related, so horses with 1 copy of allele Z have fewer severe signs than those with 2 copies of allele Z.
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.
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
Genetic characteristics are not a disease.