Background
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. Splashed white is a variable white spotting pattern characterized by a large blaze, extended white markings on legs, variable white spotting on belly, pink skin and often blue eyes. In other cases, the unpigmented areas are quite small and cannot be distinguished from horses with other more subtle depigmentation phenotypes. Splashed white horses are sometimes deaf, however most splashed white horses are not deaf. Hearing loss is due to the death of the necessary hair cells, caused by the absence of melanocytes in the inner ear. Although the majority of splash horses have pigment around the outside of the ear, the pigment must occur in the inner ear to prevent hearing loss. There are several different mutations identified that are associated with splashed white patterns. The Coat White Spotting 3 test (P595) tests for the mutation known as SW3 in the MITF gene. This test detects two variants (alleles). The allele SW3 is dominant. One or two copies of the SW3 allele result in splashed white. It is speculated that two copies of the SW3 allele are lethal (the foal dies). The allele N is recessive and does not have an effect on the basic colour.
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.pharmaDNA.com.
Age
Most coat colours and coat types are usually visible directly after birth.
Throughput
Normally the result can be expected within 15 working days. This turn-around-time starts when both the sample and the fully filled-out and signed submission form have been received.
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
This DNA test is available for the following breeds: Quarter Horse.
Sample type
For this DNA test we accept the following materials: Blood EDTA, Blood Heparin, Hair, Tissue, Semen. Please contact PharmaDNA if you wish to submit other material as listed.
Result
Coat colours are based on many genetic factors. For each factor, a separate test result will be returned.
Inheritance
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
Factors influencing coat colour and coat types are usually not related to diseases.
