The Dun Gene Information

So what does the dun gene do? It is a dilute gene that changes the coat color characteristics in
equines. Some schools of thought now believe it could be a modifying gene instead, but either way,
it is a gene that affects the coloring. It is sometimes called a primitive gene because it is believed to
have been around as long as horses have been around. It is found with more frequency in some breeds
than others. It is very prevalent in the Fjord, Mustang, and Quarter Horse breeds - but very rare to
non-existent in the TB and gaited horse breeds. The gene can manifest itself on all coat colors and
often appears with other modifying and dilute genes. It generally dilutes the body color, but leaves the
points a darker shade of the same color. It is also responsible for the primitive markings, often called
dun factor markings, you find on dun gene horses. It is a dominant gene, which means one parent
must have the gene to pass it down to the offspring. It doesn't "hide" under some coat colors like
agouti or silver dapple only to pop up generations down the line. So if you see a pedigree with several
dun horses farther back, but the sire and dam are not dun, then neither is the horse in question.

Click on the link to learn more about the dun gene and how it affects horse coat colors. You
will also find information on breeding for the grullo color in the document.