group of horses


Horse Genome Project


International Equine Genome Mapping Workshop
The 8th Dorothy Russell Havemeyer Foundation International Equine Genome Mapping Workshop took place near Newmarket, UK from July 22 to 25, 2009...[more]

Writers at the Louisville Courier Journal recently won the 2008 Media Eclipse Award for journalism based on an article about Thoroughbred racing and break-downs. They published a 3 part story, including genetics, track surfaces and medications. In connection with the genetics section they interviewed several members of the Horse Genome Project. See the accompanying links for the full stories on the 2008 Media Eclipse Award and the article itself.

Courier-Journal Web site wins award for horse project
Genetics may hold key to Injury-prone horses
[December 2008]

The first draft of the horse genome sequence was recently completed and deposited...
[JAVMA News, April 2007]

Data on Equine Genome Freely Available to Researchers Worldwide
[NIH News, February 2007]

The first genome map of a horse is complete, providing scientists with new tools for investigating equine disease. [ April 2006]



Why are there so many colors of horses?

Wild animals often have muted colors that allow them to blend into the background.  The dun coloration of the Przewalskii horse is sometimes referred to as a primitive coloration and very well may be the color of all horses 10,000 years ago.  A horse with extensive white might stand out in a herd and become a target of predators. We just don’t know. Horses were domesticated around 6,000 years ago.  But we do know that once animals are domesticated, people delight in selecting for color variants.  All domestic animals, including cats, dogs, cattle, sheep, horses, goats, and guinea pigs, exhibit a wide range of color patterns, even though they belong to the same species.  People have selected for color.

Where does the color come from?  We are just now identifying the genes responsible for the different color patterns.  There is one gene that determines whether a horse produces black pigment or only red pigment in its hairs. Another gene determines whether that black will occur throughout the body or be restricted to the mane, tail and legs.  There are several genes that dilute the red or black coat pigments to create palomino, buckskin, silver and other colors. There are several genes that produce white hairs in distinctive patterns that we call overo, tobiano, sabino or white.   Several genes interact to produce the various white hair patterns we call appaloosa.  A gene called grey will cause all colored hairs to turn white as the horse ages.

Selection for coat color was probably the first use of genetics after horses were domesticated.    A single gene can create a color change. People can see the effect of the single change. Selecting for color can be immediately gratifying as compared to selection for performance or health traits which can take generations of trial and error. 

We know the gene for tobiano creates white spots on horses but we do not know why the spots occur where they do.  For example, why do sabino horses almost always have white on the lower leg but not above the knee?   Likewise, the gene for appaloosa has been found but there are at least 10 different types of white appaloosa patterns.  The next frontier in color genetics is to understand what underlies these more subtle influences on color.


running horses

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