orses come in all kinds of colors and patterns, and even the most experienced horse enthusiasts will occasionally come across something so unusual that it stumps them. (Thank goodness for DNA testing.) But there are some basic rules of coat color genetics that you can always count on. If you have additional ones to share, please comment at the bottom of the article.
*Aramus, Wayne Newton's homozygous grey Arabian stallion. Note the porcelain white color that's common to mature homozygous greys. Photo by Johnny Johnston
Grey: A dominant gene, grey will always express itself over other color genes if a horse inherits the grey gene. It’s not possible for a horse to carry a recessive (and therefore unexpressed) grey gene, so all grey horses have at least one grey parent.
Some horses are homozygous grey, meaning they carry two grey genes and can only pass grey on to their offspring. Since grey is dominant over other colors, a homozygous grey will always produce or sire grey offspring. Homozygous greys can be found in Lipizzans and Arabians, among other breeds.
What’s the difference between a tobiano and other types of pinto coloring? A tobiano is a horse with large, rounded colored spots on a white background and it almost always has four white legs. (Very rarely, you can find a tobiano that has one dark leg — but those are usually in miniature horses or Shetland ponies. See a photo of a rare Pintabian with a dark leg below.) Unlike other types of pinto coloring, white commonly crosses over the back of a tobiano. In Pintabians, the ideal tobiano pattern is 50% color and 50% white.
It takes a total of eight generations to breed a horse with more than 99% Arabian blood. First, a purebred Arabian is bred to a tobiano of another breed, and if the resulting foal is also tobiano, that foal is bred to a purebred Arabian in the hopes of producing another tobiano. Each successive tobiano part-bred Arabian foal is crossed with a purebred Arabian for seven generations until a tobiano foal that is 127/128ths Arabian is produced. This means that 127 of the 128 ancestors in that horse’s pedigree were purebred Arabian.
Trademark Flair, a Pintabian stallion. Photo courtesy of Flair Park
Fancy Lady Flair, a Pintabian mare owned by Flair Park. Photo courtesy of Flair Park
The key is to maintain the tobiano coloring throughout all those generations. That can be hard to do, and any “crop-outs” (in this case, solid-colored horses that don’t inherit the tobiano coloring) have less value in Pintabian breeding because they can’t pass on tobiano coloring to their offspring and they aren’t eligible for Half-Arabian registration if they were the result of breeding two Pintabians to each other. (The official Half-Arabian registry won’t accept horses that don’t have a purebred Arabian parent.) However, a solid-colored horse from a Pintabian breeding program that has one purebred Arabian parent can most likely be registered and shown as a Half-Arabian and enjoyed as a riding horse.
Other challenges with breeding Pintabians is maintaining quality conformation. Sometimes a beautiful part-Arabian tobiano will have undesirable conformation faults, but it may still be used for breeding Pintabians because of its attractive coat color. As a result, it can be an elusive goal to breed horses that have tobiano coloring and ideal riding conformation and temperament in addition to satisfying the Pintabian Horse Registry’s standards of minimum Arabian blood.
Trademark Flair, a Pintabian colt with "cat tracks." He was DNA-tested and shown to be homozygous tobiano. He's also extremely unusual because he has one dark leg. Photo courtesy of Flair Park
Is there a fool-proof way to breed a tobiano Pintabian foal? Yes, as long as one of the parents is a homozygous tobiano. That means the horse carries two tobiano genes, so it always passes one to its offspring. Every foal produced or sired by a homozygous tobiano will be tobiano itself because the gene is dominant.
DNA testing can predict that a horse is probably homozygous tobiano, but there are also characteristics that indicate a horse may be homozygous:
The horse has “cat tracks” – small, round colored spots that look like cat pawprints on the horse’s body.
If the horse is of breeding age and has only produced or sired at least 10 tobiano foals (and no solid-colored foals) out of solid mates, the horse is probably a homozygous tobiano.
The horse is a product of two tobianos bred to one another. In Pintabians, this means both parents are at least 99% Arabian blood. Each parent could contribute a tobiano gene to the foal, making it homozygous for tobiano.
A few years ago, a uniquely-colored filly named Eclyse (pronounced “uh-KLEE-suh”) made a splash when she appeared at a German safari park.
Eclyse, a zebra/horse hybrid foaled in Germany.
Eclyse’s dam, Eclipse, was given a vacation in Italy where she lived in a herd of horses and zebras. One of the zebras, a stallion named Ulysses, had a special relationship with Eclipse during her stay. When the mare returned to the Zoosafari Park in Schloss Holte Stukenbrock, Germany, near the Holland border, she delivered a surprise foal – a “zorse”!
Just like the name sounds, a zorse is a hybrid zebra/horse. Like mules and hinnies, they are generally sterile and exhibit traits of both parents. In Eclyse’s case, she inherited a tobiano gene from her horse dam and zebra markings from her sire.
Eclyse's unique pinto markings on her head and neck.
Eclyse is a good example of how dominant the tobiano gene is. Any time a horse (or horse hybrid) inherits at least one tobiano gene, tobiano is always expressed and it determines where the colored patches appear.
I wasn’t able to find a picture of Eclyse’s dam on the web, but we can make a couple of assumptions about her:
She’s a tobiano
She may be a bay tobiano
We know for sure that Eclyse’s dam is tobiano because zebras don’t carry the tobiano gene, and tobianos must always have at least one tobiano parent. My guess is that Eclyse’s dam is a bay tobiano because Eclyse inherited her father’s stripes on top of a brown coat color. If you look up zorse on Google, you’ll find a lot of different photos of zorses and many of them seem to retain the base coat color of their horse parent. If you know what Eclyse’s dam looks like, please leave a comment.
The public can see Eclyse in person at the Zoosafari Park in Germany. Below is a video with some good close-up footage of this unusually marked hybrid filly.