At Embark, we strive to provide the most comprehensive testing service available, continually conducting research and collaborating with leaders in the field to add new health conditions and traits tests to our Embark for Breeders suite of products. This process includes adding new probes to the research-grade microarray we use to test each dog’s DNA sample as new discoveries are published. Whenever possible, we also update the results of previously tested dogs to include the new information at no cost.
We are pleased to announce a highly requested physical trait test is now available: White spotting via the “S Locus” (the MITF gene). If your dog was tested with an Embark for Breeders or Breed + Health kit (no matter which microarray version they were tested with), your dog’s trait results have been updated with their genotype. Simply log in to your Embark profile, select your dog, and click “traits.”
The S Locus, MITF, controls where pigment is produced in a dog’s coat and skin. An insertion near the MITF gene turns off pigment production in the coat and skin, resulting in white hair and/or pink skin.
Dogs with two copies of the insertion (sp) will likely have breed-dependent white patterning, with a nearly all white, parti, or piebald coat. Dogs with one copy of this variant will have more limited white spotting and may be considered flash, parti or piebald.
S Locus testing may be of interest for the following breeds (not intended as a comprehensive list):
- Australian Shepard
- Basset Hound
- Border Collie
- French Bulldog
- Cavalier King Charles Spaniel
- Chinese Shar-Pei
- Cocker Spaniel
- English Cocker Spaniel
- German Longhaired Pointer
- German Shorthaired Pointer
- German Wirehaired Pointer
- Portuguese Water Dog
- Shetland Sheepdog
- Saint Bernard
To see a complete list of traits tests included in the Embark for Breeders products along with explanations for each, please visit our traits page.
The MITF insertion variant does not explain all white spotting patterns in dogs, and other variants are currently being researched. For example, some dogs may have small amounts of white on their paws, chest, face, or tail regardless of their S Locus genotype. This is referred to as residual white. Dogs of some breeds are fixed for Irish spotting, a pattern of white undersides, often a white neck collar, and sometimes white facial markings. Research into the genetics of Irish spotting is ongoing.
One such example of ongoing research is that of Mary Langevin, a prominent researcher on merle, who is using the raw data provided by each Embark DNA test to look into “white head”. For more information on this research visit her site here: Canine Whitehead Research.
For a complete explanation of white spotting and the S-Locus, please reference this excellent summary: http://www.doggenetics.co.uk/white.htm
For the scientific basis of the S-Locus and its impact on dog traits, please reference the full scientific paper here: Karlsson et al 2007