Sabino is a pinto pattern often confused with overo. It differs from overo in these ways:
-- The edges of the white areas of a sabino are jagged, feathery, or "roaned." The edges of the white areas of an overo are more crisp.
-- Sabinos often have a white feathery-edged patch underneath their throat. Overos don't necessarily have this.
-- Sabinos rarely have blue eyes. Overos often do.
-- Sabinos often have hind stockings in which the white area seeps up the front side of the leg; also, if they have no white stockings on their forelegs, they often have a white patch on the knee.
Sabino is caused by the dominant gene Sb. Homozygous SbSb horses are often almost solid white; heterozygous Sbsb horses display "normal" sabino patterning, and homozygous sbsb horses are not sabino. There is no lethal factor associated with the sabino gene.
Splashed white is another pattern that's often confused with overo. Its characteristics are a white belly and legs, white on the back of the butt, and a white face with blue eyes. Yes, that sounds remarkably like overo, but overos usually do not have white legs.
Splashed white is caused by a dominant gene, Spl.
A true white horse is caused by the W gene. This color is referred to as dominant white, since W is a dominant gene. The presence of the W gene masks the expression of all other color genes (a mechanism called epistasis). White horses are born solid white with pink skin and usually brown eyes. All dominant white horses are Ww genotypically. Homozygous WW foals die in utero or shortly after birth.
White horses are not albinos. An albino would have pink eyes and would not have the brown or blue eyes characteristic of a white horse.
There are other colors that resemble white. They are:
Cremello and perlino. These aren't white, they're cream, and perlinos have pale reddish-tinted manes and tails.
Grey. An old grey horse may have a white coat, but its skin remains dark, unlike the pink skin of a white horse. Also, greys are born colored and get whiter with age, while a white horse is born white.
Extensively marked pintos.
Some pintos, particularly sabinos, may look white, but this is caused by a spotting gene. Dominant white is caused by a solid white gene. A sabino will often have some color on it somewhere, perhaps atop the head or at the dock of the tail, but a white horse is solid white.
All of these colors are different genetically, so not only do they not look the same visually, they will also breed
