Varnish roan is thought to occur due a single, simple dominant gene on equine chromosome 1 (ECA1). It also appears that specific white patterning genes produce the assorted blanket, leopard, and snowflake coat patterns.
Varnish roan is thought to be caused by a single, simple dominant gene on equine chromosome 1 (ECA1).  Specific white patterning genes are responsible for the various blanket, leopard, and snowflake coat patterns.