Embark for Breeders Dog DNA test includes a variant in the HPS3 gene that causes a coat color referred to as “cocoa.”
What Does Cocoa Look Like Phenotypically?
This variant causes dogs that would otherwise produce black pigment to produce dark brown pigment in their skin and hair. Dogs must have two copies of the co allele to show the cocoa color phenotype. Thus far, this variant has only been observed in French Bulldogs.
The normal brown genotype, displayed on a dog’s Embark results as bb at the B (TYRP) locus, may mask the cocoa phenotype (represented by the genotype coco on results), so dogs that are both bb at the B locus and coco at the Cocoa locus might have mid/light brown skin and hair like other bb dogs.
The cocoa color will only be visible in a dog’s coat if the coat contains dark hair. This means that dogs with the coco genotype at the Cocoa locus that are also ee at the E locus will not show cocoa in their coat but should show it in their skin. This may also occur in dogs that are considered “clear sable” and express the ay allele at the A locus.
Left: “normal” brown color. Right: “Cocoa” color
Image source: Kiener, S. et al. (2020). [Figure 1 ]. Genes (Basel). https://pubmed.ncbi.nlm.nih.gov/32526956/
Interestingly, the cocoa coat color sometimes starts out very light – almost like dilute brown – and darkens as the dog reaches maturity.
Left: coco dog as a puppy. Right: Same dog as an adult.
Image source: Kiener, S. et al. (2020). [Figure 1 ]. Genes (Basel). https://pubmed.ncbi.nlm.nih.gov/32526956/
What possible Genotypes may be reported?
A dog’s Embark results may be displayed as one of the following:
- Genotype- NN; Predicted phenotype- No effect on coat/skin color
- Genotype- Nco; Predicted phenotype- No effect on coat/skin color
- Genotype- coco; Predicted phenotype- “Cocoa” (dark brown) coat and skin, unless masked by the B, A, or E locus genotype
From time to time, Embark updates our genotyping technology to add additional genetic markers. The technology in use at the time of genotyping may impact which results we can provide. This Cocoa result will be displayed for all dogs, regardless of breed, tested on our V5 microarray (approximately those tested after late November 2020) and to the present. To see which microarray version your dog was tested on, learn more here.
