Dog Coat Color Piebald, Parti or Random White Spotting


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Dog Coat color (S Locus) Parti, Piebald, or Random White Spotting


There is no single basis for white spotted patterns that occur in animals like cats, dogs and horses. In horses random white spotting, or deletion of color, has been determined to be caused by more than half a dozen known genetic factors.  In more than 25 different dog breeds, a mutation found in a gene called Microphthalmia Associated Transcription Factor-(MITF) is associated with a piebald spotting.


In many breeds piebald behaves as a dosage-dependent trait. This means that dogs like the French Bulldog who have a single copy of the MITF variant will express a limited white spotting pattern, while dogs that have 2 copies (S/S) of the variant will exhibit more white with very little color. In some breeds dogs that are (S/S) are completely white while dogs that are (n/S) have what is referred to as mantle.


As with horses and other animals, dog breeds with white spotting patterns can be affected by additional mutations in MITF and or other genes that effect coat color deletion and distribution. For example, the irish spotting pattern seen in many breeds of dogs (such as Collies) is not caused by this mutation.


S Locus Testing:

Animal Genetics offers a test for the S-Locus to determine allele a dog is Parti, Piebald, or Random White Spotting Dogs can be DNA tested at ANY age.

Testing Is Relevant For The Following Breeds:

Australian Shepard, American Cocker Spaniel Basset Hound, Beagle, Border Collie, Boxer, French Bulldog, Cavalier King Charles Spaniel, Chihuahua, Chinese Shar-Pei, Dachshund, English Cocker Spaniel, French Bulldog, German Longhaired Pointer, German Shorthaired Pointer, German Wirehaired Pointer, Goldendoodle, Havana Silk, Havanese, Labradoodle, Newfoundland/Landseer, Pointer, Poodle, Portuguese Water Dog, shetland sheepdog, Shar Pei, Saint Bernard, Whippet, Yorkshire Terrier

Sample Type:

Animal Genetics accepts buccal swab, blood, and dewclaw samples for testing. Sample collection kits are available and can be ordered at Canine Test Now.


Animal Genetics offers DNA testing specific for the mutation in MITF known to be associated with piebald/random white spotting. The genetic test verifies the presence of the mutation and presents results as one of the following. Note- white patterns will vary among individuals and from breed to breed.

S-Allele Results:

S/S Piebald The dog carries two copies of the dominant MITF S allele. The dog will have limited coat color and will always pass on the "S" allele to any potential offspring.
n/S Carrier The dog carries a single copy of the S allele. In some breeds the dog may have limited random coat color deletion. The dog can pass on either allele to potential offspring.
n/ n Negative No copies of the MITF S allele where detected. The dog will not pass the MITF mutation on to offspring.