What is the EM allele, and how does it work?

The E 

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  An allele is the specific genetic variant responsible for creating a dark mask on a dog’s face. It is located on the E-locus, which corresponds to the MC1R gene.

Here is how the E 

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  allele works:

• Dominant Trait: The E 

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  An allele is dominant, meaning a dog only needs to inherit one copy of it to possess a genetic mask. If a dog is homozygous for the trait (meaning it inherited two copies of the allele), all of its offspring will also possess a mask.

• Interaction with the Base Coat: The mask caused by the E 

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  The allele will be visible only in dogs with a lighter base coat, such as fawn or brindle.

• Camouflaged on Dark Coats: If a dog with a dark coat color—such as solid black, blue, harlequin, or merle—inherits the E 

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  allele, the mask will still be present but completely hidden, as the dark mask blends into the dog’s dark base color.

Because the E 

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  An allele can be hidden by dark coats; breeders can use DNA testing to identify if a solid black or blue dog is a secret carrier of the mask trait.