Dominant White | Equine Testing | Animal Genetics



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Dominant White (W3, W5, W10, W13 and W20)


White coat color or de-pigmentation phenotype in horses is inherited as a monogenic autosomal dominant trait showing a variable expression of coat depigmentation. Dominant white” refers to a class of white spotting patterns in which a horse with one copy will display markings on 50-100% of the body. Unlike other extreme white patterns, this trait generally leaves the eyes dark. Dominant White markings are a result of various mutations occurring in the Kit gene.

Allele Breed Origination
W1 Franches Montagnes Cigale, 1957
W2 Thoroughbred KY Colonel, 1946
W3 Arabian R Khasper, 1996
W4 Camarillo White Horse Sultan, 1912
W5 Thoroughbred Puchilingui, 1984
W6 Thoroughbred not published, single horse
W7 Thoroughbred not published, single horse
W8 Icelandic not published, single horse
W9 Holstein Horse not published, single horse
W10 Quarter Horse GQ Santana, 2000
W11 South German Draft Horse not published
W13 Quarter Horse Haase B et al.
W20 Gypsy and many other breeds Hauswirth R et al.
W22 Thoroughbred Airdrie Apache, 1993

Dominant White is a dominant physical trait, so if a horse has one or two copies of the Dominant White gene, the horse will display the pattern associated with the gene mutation. Testing can determine if the coat pattern of a horse is actually Dominant White (W3, W5, W10, W13 and W20) or if a different modifier is present. This can be particularly useful in horses that have additional patterns, such as Frame Overo and Tobiano. DNA testing for Dominant White (W3, W5, W10, W13 and W20), also identifies if a horse has 1 or 2 copies of the gene, which can be an informative tool for breeders.

If you believe your horse is included in one of these 11 families identified as carrying a Dominant White allele and you would like to confirm if it carries the specific KIT mutation, Animal Genetics has developed genetic tests for many of these alleles and can verify whether or not the horse carries the suspected allele. Please call our office or email us for more information.

Test Results:

Animal Genetics offers DNA testing for Dominant White (W3, W5, W10, W13 and W20). The genetic test for each verifies the presence of the specific mutation and presents results as one of the following:

W#/W# Homozygous Indicate that the horse carries two copies of the specified Dominant White KIT mutation.
n/W# Heterozygous Horse carries one copy of the specific Dominant White KIT mutation that was tested for. Horse will usually exhibit a coat pattern phenotype associated with the particular mutation which could vary greatly from small areas of white to a completely white coat, depending on which mutation is involved.
n/n Negative This horse does not carry the specific Dominant White gene mutation that was tested.

    Submit a Sample for Testing:

    To submit a sample for testing please click on ORDER and download a sample submission form. Then follow the sample collection and submission instructions.


    Please see our Equine Fee Schedule for all equine testing rates.