While it's true that many can spot a roan horse, the question remains: can you distinguish between genuine roans and other phenotypes that have roaning? Join us on a journey to uncover the nuances of roan.

Many breed registries, including the AQHA, offer a limited array of options for horse registration when it comes to coat colour and pattern. There is no distinguishing betwen roan, rabicano, sabino, or any other white pattern. However, in our modern era, we are fortunate to wield the power of genetic testing, enabling breeders and horse owners to unravel the mysteries of equine genetics and make informed decisions.

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What is a true roan?

A true roan is a horse with a coat pattern that presents as white hairs intermingled with coloured hairs across the body, creating a stunning contrast with the base colour. What distinguishes roan from other patterns is that it is uniform throughout the body and spares the horse's head and legs, making those areas less effected by the roaning effect. This trait is unlike many other genetic modifiers such as the cream gene, or champagne, which dilute the horse’s entire body.

While roan can appear on horses of any base colour, it's most easily discerned on darker coats due to the stark contrast it creates. Roan, not unlike other genetic markers, can also be a expressed atop a number of other genes that can make it difficult to distinguish exactly what is going on. A red (sorrel/chestnut) horse with the roan gene is commonly referred to as red or strawberry roan, black base with the roan gene are commonly referred to as blue roan, and bay bases are simply called bay roans. The trio of core bases aside, any other combination is just referred to as base (plus modifiers) + roan. For example, a Palomino horse that is heterozygous for the roan gene (n/Rn) is a 'Palomino Roan.' It's also important to note that on lighter combinations, such as palomino or cremello, identifying the roaning effect can be more challenging due to the reduced contrast.

Roan is a complete gene, in that heterozygous and homozygous differ only on paper and how they can reproduce, but will not appear differently to the naked-eye. A heterozygous roan horse will carry one copy of the gene (n/Rn), where homozygous horses will have two copies of the gene (Rn/Rn) but you will not be able to tell from simply looking at them. For more information regarding heterozygous and homozygous traits, read our artice here.

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Roans of a Different Colour

The roan gene itself is dominant, which means that for it to be passed on to offspring, at least one of the parents must carry the roan gene (meaning they must be heterozygous (n/Rn)). One of the interesting aspects of a true roan horse is that it is often born with a solid coat colour, though not always. In these cases, when the horse sheds its first foal coat that the roan pattern begins to emerge. In these horses, the roan colouring remains consistent and doesn't lighten as the horse ages – though you may see seasonal changes due to longer or shorter hair-coats. This remarkable permanence sets roan apart from other coat patterns, where permanent changes over time are not uncommon, such as the gray gene.

Another intriguing aspect of roan is its reaction to injuries. When a roan horse sustains an injury, the subsequent healing process results in the hair growing back in its base colour. For example, if a red roan horse experiences a cut or abrasion, the hair that regrows in the affected area will be the original solid red (chestnut/sorrel) colour. In contrast, injuries to horses with different coat patterns may result in hair growing back white. In the example above, Funny B Blue Muchaman, you can see these injury marks, or 'corns' on his neck.

While roan is a distinct coat pattern, it can sometimes be confused with other white markings that are caused by different genes. For instance, the American Quarter Horse Association recognizes sabinos and rabicanos with sufficient ticking as roans, as there is no separate colour category for these patterns. Unfortunately, this means that horses are improperly or incompletely registered all the time, forcing horse owners to invest in genetic testing to uncover the truth of their horse. However, some specific colour registries such as the American Roan Horse Association only allow registration with confirmation of roan zygosity present (though not in all cases, but at least in the case of my mare which was registered as a red dun with the AQHA, as I was unable to add 'roan' to her papers at time of registration; she is in fact a red dun roan).

It's essential to distinguish between a true roan, the roaning effect caused by the sabino gene, and rabicano patterns. These are the most commonly confused patterns for true roan. While sabino and rabicano can create a roaning effect on the body, they are not products of the roan gene. In a true roan, the 'Rn' gene is responsible for the distinct roaning pattern. Sabino, on the other hand, often presents with facial white markings, a white chin spot, white socks on the legs, and body roaning – making it distinguishable from a true roan. Transversely, a rabicano marked horse will often have vertical “barring” on the ribs, roaning/ticking intensified on the flank, and a “coon” tail. True roan horses (unless they are in combination with rabicano) will not have these traits. Rabicano horses also don’t have roaning uniformly throughout their bodies like a true roan horse will. Another distinct marker is that many rabicano horses won’t have any white hairs on their necks/shoulders where a true roan horse will.

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Rabicano, Defined

Rabicano is a distinctive horse coat pattern featuring white ticking which is often confused for roan, it is characterized by white hairs concentrated primarily at the tailhead and flanks, where the hindquarters meet the body. The term "rabicano" originates from the Spanish words "rabo" for "tail" and "cano" for "white" – which is a main component of this gene. While minimal rabicano expression may include a few white hairs in these regions, horses with chestnut or chestnut-based coats are more likely to exhibit extensive white patterns. It's worth noting that rabicano is a roaning pattern, distinct from true roan, and its genetic mechanisms are not yet fully understood. That said, lets have a look at a classic visual representation of rabicano:

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What's a Skunk Tail?

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So what is sabino?

Sabino patterns display roaning, white patches with uneven or jagged borders, belly spots, white beyond eyes or chin, white above knees or hocks, and splash-like marks. Some show partial roan on the body, often the barrel and flanks. Sabinos can also have one or two dark legs but often feature four white legs. The sabino markings can also range from subtle facial or leg white to nearly all white coats in those that are maximally expressed. With all of that noted, let's take a look at a stallion who carries the sabino gene:

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What happens when these genes stack?

With what we now know about Roan, Rabicano, and Sabino – let's see if we can decipher what's going on with a horse that has a series of markers that point to multiple genes. Technically speaking, a horse could be a roan sabino rabicano, and possess all three genes, but we'll start with a stallion that has two of the three:

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One final thought...

We feel that this is worth mentioning, even though this is much more common in the Thoroughbred world. There is a common misconception that leads owners/breeders to refer to and register their foals as gray/roan but are simply gray horses in the stages of progression of the gray gene. Now, that is not to say that a gray horse could not also possess the roan gene (ref. Two Legitt who is a gray (buckskin roan) stallion); but in this instance, we have a gray colt that is likely not roan at all:

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