The Horse Colors Site

The Pangare, or Mealy, Modifier

This is a subject that is the center of much discussion and dissension.

In the past this has been suggested as a single gene that causes a bay to have the "wild donkey" look, a chestnut to have the pale muzzle, underbelly, etc. like the typical Haflinger or Belgian, and a black to be a seal brown (also known as brown, dark brown, black bay and dark bay.)

However, newer research has proven this theory false. See the Base Colors page for a genetic explanation of seal brown. Now that there is a test for the "a" allele, and we know that seal browns do not test "a", they cannot be black + pangare or black plus anything. In addition, population studies had already shed doubt on the theory (there are breeds in which seal browns outnumber blacks by about 10 to 1, so if seal was caused by a pangare gene, it should occur in the majority of bays and chestnuts, as well - but it doesn't. In fact it's very rare to find a pangare-marked bay or chestnut at all in that breed..)

We have been shown photos of pangare-marked horses from parents that had none, and horses with no pangare from parents which were both pangare-marked. This rules out a simple, single gene, either dominant or recessive. It is now believed to be some sort of multi-gened effect, like flaxen. But nobody has studied it thoroughly yet, to our knowledge, so many questions about it remain unanswered.

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