Sabino Horses

What is Sabino?
Sabino (Sah-BEE-no) is a white spotting pattern that is usually included with Frame and Splash and given the generic name, Overo. This is because it displays pattern characteristics which can be very similar to either of these patterns.

The term Sabino comes from northern Europe and in Spanish means "pale red" or sometimes "roan". Sabino in South America specifically means flea bitten Grey, especially Grey that has red flecks instead of black. In the United States it is a term used for this particular pattern and although it may resemble Roan or Grey at times, it should not be confused with either as it is totally separate.

Sabino is very prevalent and occurs in many, many breeds such as: purebred Thoroughbreds, Tennessee Walkers, Akhal-Tekes, American Baskir Curly, Spanish Mustangs, Quarter Horses and Morgans, just to name a few. There are actually very few breeds in which Sabino does not occur - Icelandic Horses being one.

Clydesdales and Shires are exclusively Sabino, although these breeds calls it "Roan". Some breeds such as the Gelderland are also almost exclusively Sabinos, having the large facial white, chinspot and high leg white as one expression that is found with this pattern.

One Sabino characteristic is a white marking on the face which can vary from a few white hairs to a large blaze. Anoter very common characteristic of Sabino is white on the lower lip and/or chin, ranging from small to large. Some very minimal Sabinos may not have this characteristic white spotting but will have other traits of the pattern. Even though facial white is common, even to the point of causing a "bald" or "apron" marking at times, blue eyes not considered a trait of the pattern and if it does occur in conjunction with Sabino it is usually a trait of a certain line of horses and these horses usually only have one blue eye, not two. (The Khemosabi line in Arabians is very prevalent with Sabino, some of which have blue eyes), or it is being caused by another gene.

Leg white that ranges from a coronet to a high stocking is also common. There really is no rule as to how many legs are white, but generally at least one will have some white on it. Patches on the knees, that are not connected to any other white, are also a trait that can occur with Sabino.

Another common characteristic of Sabino is roaning, this is the most minimal expression of Sabino. This can vary from a small amount of roaning concentrated in an one area of the horse to roaning that covers the entire body. It's also common for roaning to be found on the head and legs, especially if a white marking is present. This roaning will vary in extent from very minimal to very extreme and occurs to some extent in all breeds which have Sabino.
Sabino can also cause roaned areas that may not be present at birth and grow with age.

Body spotting is can range from very minimal that usually begins in the belly area to maximum effects involving the entire body. The minimal expressions can be seen as roaning, to speckled areas to larger white patches. Most Sabinos are flecked or roan and this is especially true when a horse has extensive spotting. Towards the more maximum expression of the pattern, some Sabinos can look very similar to Splashed Whites, the difference being that Sabinos generally have some roaning to the edges of their white. Splash spots (without Sabino present) should be crisp and clean.

At it's most maximum expression Sabino will cause the horse to be totally white, if any color remains it's usually as roan or speckled on areas such as the ears, tail base, chest and flanks, these areas may not have colored hair, it may just be the colored skin showing through the white hair. In the past, a horse colored like this was said to be "Dominant White". This dominant gene, labled W, was thought to be lethal when homozygous, like Frame. The problem with this theory was that many horses who were "Dominant White" didn't have the necessary "Dominant White" parent, the rule of dominant genes being that at least one parent must have it for the foal to have it. Research has shown that these "Dominant White" horses who are usually born from non-white parents are really Sabinos with the maximum expression of the pattern. The theory of the "Dominant White" gene has been left in the past, especially since there has never been any scientific evidence to support that it exists.

Sabino is the most common cause of solid colored horses with "chrome" or horses that have lots of facial white and high leg white but no body spots, although it's common to see small to large belly spots. These horses are thought to be "solid" with "normal" white markings, but are in fact Sabinos and depending on the horse they are mated with they could be just as likely to produce a Sabino foal as another Sabino with more pattern expressed. An example of this is the many Quarter Horses that are minimal expression Sabinos, these horses can and do produce full patterned "Paint" foals that are called "crop-outs". Sabino also very commonly mixed with Frame and Splashed White in Miniature Horses, American Paints and Pintos.

Some in the equine genetics community believe that Sabino is a polygenic trait which means there are more than just one gene controlling it's expression. This group also is inclined to believe that Sabino is the cause for all white markings in horses, the polygenic theory would support this claim. After studying Sabino in many different breeds, I am inclined to be one of those that believes both theories. Further research by breeders and scientists will hopefully shed some more light on this fascinating pattern.

Due to Clydesdales & Shires being exclusively Sabino, it's very unlikely that Sabino is lethal in homozygous form as many horses in those breeds are very sure to be homozygous for the Sabino allele.