Domino: In Depth About The Husky Masking Gene

What is domino?

Domino is a term for a group of E locus locus mutations, which have a rather complex effect on coat color. It always wipes some eumelanin away, and so the basic A locus pattern the dog shows turns into different version of it: 

For example, tanpoints get FAR bigger points, agoutis will be just paler, especially from face, sables turn more clear. Even a/a recessive solid darks get some kind of paler points. Also KB dominant solid dark dogs are affected; their coat turns also paler. 

How does it work?

Domino on average turns pheomelanin paler than it would have been, and often adds some white, most often to the middle line of face. A domino patterned dog often (but not always) has the "domino nose" or “snow nose” where there is a vertical pink stripe in the middle of the nose leather, with crisp edges. 

Three this far known domino mutations are eg (mainly in sighthounds), eA (mainly in northers spitz type breeds) and eh (only in English Cockers). There could be others, too. In sighthounds, domino is most often called grizzle, except in Afghans, where it is called domino. In English Cockers it is called sable, although it is not related to real sable. In Siberian Huskies it is often called "color and white". 

Color testing labs can call domino mutations with fancy made up names like "widow's peak pattern" or "ancient red".

How Does It Show Up On Testing?

Domino will be referred to as Ed or Ea depending on the researcher or testing  company used! They are essentially the same thing.