THHNPinto.pdf

HORSE COLOR

Lesli Kathman, 4700 Lone Tree Ct., Charlotte, NC 28269 <leslikathman@earthlink.net>

Pinto Patterns

In past installments of this column, we have mostly dealt with

dilution genes, which can be classified as effecting red or black hairs

(pigment specific), or the body or points (location specific). At this

point we will be moving on to the pattern genes, which mask specific

areas with white rather than alter the base color. For this reason the

pattern genes are best understood in terms of where these “masks”

first appear (the points of origin) on the most minimally marked

animals, and the directions they spread (the pattern progression) on

more extremely marked animals. Variations in these two aspects -

“points of origin” and “pattern progression” - are especially important

with pinto patterns since they make it possible to tell one pattern from

another. (Note: In the years since I wrote this article and started using

these two phrases to help explain pinto patterns, I have found it also

helpful to talk about where the white does not go in each pattern, the

“areas of exclusion”. Since this article is older, that aspect of pattern

progression is not included.)

It should be noted, however, that pattern progression in pintos

applies to groups of horses showing varying amounts of white, and

not the individual horse itself, since these patterns are fixed from birth

and do no change with age.

Of the patterns of white found in horses, those that make up the

pinto patterns are probably the most popular at the moment, both in

the real horse world and in our industry. There are currently four

patterns in this group. The first one, tobiano, is probably the best

known, while the remaining three are frequently lumped as a group

and collectively called overos. While this is not inaccurate - they are

indeed all overos - it is also not particularly helpful since frames,

splashes and sabinos vary a great deal from one another. They are

also the result of separate genes, and not all breeds said to come in

overo actually have the three different genes in their breeding group.

Arabians, for instance, can be found with sabino patterns, but not

frame or splash. Someone learning that Arabians could be “overo”,

but not aware that there were three different types of overo, might

choose to paint an Arabian model with a frame pattern, which would

be unrealistic. For that reason I am a big advocate of understanding

the differences between the overo patterns, and using specific terms

for them whenever possible.

The following are overviews of the pinto patterns in horses. In

subsequent issues, we will look at each one more closely.

Although tobianos do look like they have dark markings on a

white background, it is much easier to understand how the patterns

work if the subject is approached in terms of white markings covering

the base color. Although the pattern progresses as dark spots grow in

size and frequency until they run together and make more of the

horse dark, pinto breeders tend to define a horse by how much white

is present. Therefore, a horse with a lot of spots that have run

together (making him predominantly dark) would be termed by pinto

breeders as “minimally marked”. Remember that the points of origin

and pattern progression are being described as the start of the white

areas, so this approach will seem to be looking at tobianos

backwards, in a way!

This Saddlebred gelding has a very typical tobiano pattern.

Points of origin: On all four legs (solid legs are exceedingly rare,

and found on only the most minimally marked tobianos), along the

topline between the neck and withers, and at the base of the tail.

Pattern progression: On a minimally marked tobiano, usually

what is seen are high stockings that appear to come to a point along

the side of the leg, and a small patch that crosses the neck or withers.

There may also be white at the base of the tail which turns the top half

of the tail white (a dark tip to the tail will often remain, even in the

more extremely white tobianos). As the pattern progresses, the patch

along the neck will spread down the back, eventually joining with the

patch at the tail. At the same time, the white will spread down the

sides roughly perpendicular to the ground. As more white appears,

the individual (dark) spots become more obvious.

Tobiano

Tobianos look like white horses with dark spots, as opposed to

the other three patterns that tend to look like dark horses with white

spots. Their face markings tend to be conservative and the eyes are

usually dark. Tobianos almost always have four white legs and the

white on their body will usually cross over their back or neck. The

borders of the spots are usually rounded and well-defined, but

sometimes the placement of many smaller spots in one area will make

the white areas seem jagged. However, even in the wildest tobiano

pattern it is usually possible to see how roundish spots grew together

to form the pattern.

Frame Overo

In many ways, frame overo is opposite in appearance to tobiano.

Frame overos appear to be dark horses with white spots that

resemble torn paper. Bald and apron faces are quite common, but the

leg markings are conservative. The markings tend to concentrate on

the neck, shoulder and flanks, and the pattern does not generally

flamboyant markings, and indeed the pattern does seem to work by

extending the white normally found on the face and legs of solid-

colored horses. Usually there will be high stockings, especially on the

hind legs where the markings often extend up the stifle. Patches will

appear along the belly or girth, and sometimes on the legs as well,

more often on the knees. There is a lot of facial white, although not

as extreme as it is seen in frames or splashes, and it tends to spread

under the jawline rather than across the face. It is along the belly and

up the sides of the body that the pattern usually grows, as well as up

the stifle and along the hindquarters. Sometimes this progression up

the hindquarters will form a peculiar jagged line straight up the

hindquarters to the croup. On the forelegs the markings will

eventually move up the chest and from there run up the neck, where

in the more extremely marked animals it will eventually join the white

along the jawline. The tail and mane will often remain dark, though

roany sabinos often have mixed manes and tails. The most extreme

sabinos are born white, often with faint ticking on the skin. The eyes

of sabinos are typically dark, even when the foal is born white.

Splash Overo

This frame overo displays white in the typical areas - the face, the broad sides

of the neck and barrel, while the hindquarters and legs remain mostly dark.

This is probably the least known of the overo patterns, although it

is actually more widespread across a variety of breeds than the

better-known frame overo pattern. Horses with this pattern look as if

they have been dipped feet-first into a vat of white paint. Splash

overos have more face white than any other pattern, with bald faces

standard and paper faces (where the entire head is white, except the

ears) not at all uncommon. The legs are also typically marked with a

great deal of white. The edges of the markings are even, without

roaning or flecking. The tail may be dark or light, and occasionally a

light tip will be seen on an otherwise dark tail. Both eyes are typically

blue, though some minimally marked horses will only have one blue

eye or a partial blue eye.

Points of origin: On the face including the eyes, on the legs, and

on the belly.

cross the topline or extend to the hindquarters. The tail is almost

always dark. Blue eyes are occasionally seen, but they are not a

hallmark of the pattern in the way that they are for splash overos.

Many geneticists believe that this is the pattern involved in Lethal

White Syndrome. (Update: Scientific testing has since proven this.)

Points of origin: On the face but not necessarily including the

eyes, on the sides of the neck, and on the barrel.

Pattern progression: In the most minimally marked frame

overos, there will be a bald or irregular face marking and a small

patch on the side of the body without coming too close to the edges of

the horse, when viewed in profile (hence the name - the dark areas

“frame” the pattern). As the pattern progresses, more white will

appear on the sides of the neck and body. Because the white

concentrates on the body and neck, and grows towards the shoulder

area, the hindquarters often remain dark even in more extremely

marked horses. Irregular patches do occasionally appear on the

forearm and stifle, but are extensions of the body pattern rather than

extensions of the leg markings.

Sabino Overo

The sabino pattern is probably the most common form of spotting

in equines, and is known by a variety of names depending on the

breed or geographical area; “wild white”, “flash markings”, “calico”,

“particolor”, and “lit-up roan” are just a few. The sabino pattern is an

exaggeration of the face and leg markings found on solid horses, but

beyond that generalization the pattern has a great deal of variation.

Some sabinos will look blotchy, with roundish spots of dark hairs in

the middle of their white areas, giving them an almost appaloosa-like

appearance. Some will have ragged white markings with little roaning

at all, while others will be heavily roaned and ticked with no distinct

areas of dark and white. The current belief is that the sabino pattern

is actually the result of a set of genes, which would account for the

variation and for the fact that certain variations are found in some

breeds but not others.

Points of origin: On the face and under the jaw, up the legs

along the stifle, and under the belly, possibly the girth area.

Pattern progression: Many people mistake these overos, at least

in the pattern’s more minimal expressions, as being solid horses with

This Paint gelding shows how the sabino pattern can appear to be just a

slightly more flashy form of ordinary stockings and blazes. Minimally marked

sabinos - horses with only a little less white than this horse - will often slip

through registries that do not register “pintos” because their patterns are seen

as attractive markings, rather than as less extensive versions of a pattern.

Although it might look flaxen, the tail on this splash overo is red chestnut. The

lighter bottom is white, and is part of his pinto pattern. This trait, along with

his completely white face and blue eyes, is typical of splash overos.

When a horse inherits more than one pattern, for the most part

the end result looks very similar to what would happen if the two

patterns overlapped. For example, if you took a sketch and shaded in

all the area of white from a given tobiano pattern, and then took the

same drawing and shaded in a frame pattern, in the end the shaded

areas would look a lot like a pattern that might be seen on a tobiano-

frame combination. Most of the time, this is how combination patterns

work. The exception to this ‘overlapping rule’ is sabino. In many

cases sabino does not just cause overlapping, but also causes the

edges of the other pattern(s) to appear irregular, lacey or roaned.

No matter which patterns are involved, two things are true of

combination pintos; the horses more reliably produce colorful

offspring, and they themselves tend to be more extremely marked. If

you look at the points of origin for the various patterns, you will quickly

see that most of the patterns start from a different area, and move in a

different direction from the others. Therefore, it comes as no surprise

that when horses carry multiple patterns - all with diverse areas

inclined to be white - the end result is a horse with more than an

average amount of white.

Pattern progression: In its most minimal form, this pattern can be

hard to distinguish from a minimally-patterned sabino, since the points

of origin are much the same. What will differentiate the two are the

edges, which are even like those seen on the tobiano, and the eyes,

which are almost always blue. As the pattern progresses, the white

on the legs will extend as if the horse was dipped further and further

into a bucket of white paint. From the belly it will travel up the sides of

the body, often crossing the middle of the back, leaving a dark area on

the hindquarters and on the lower neck and shoulders. Eventually the

only remaining dark area will be the ears. While minimal splash

overos are occasionally seen with only one blue eye (or even a partial

blue eyes), the vast majority will have blue eyes.

horse color that originally appeared in The Hobby Horse News, a magazine for the

model horse collecting community that is no longer published. The articles may be

copied for personal, non-commercial use. Individuals may also offer the files for

downloading provided they are properly attributed, but inclusion in commercial

publications (magazines, newsletters, books) is forbidden unless written

permission is obtained from the author.

“Toveros” or Combination Overos

Although the American Paint Horse Assocation only registers

horses as being tobiano, overo or tovero (a combination of the first

two), it is quite possible - even likely when horses are being bred

specifically for color - that a horse will have more than one of the four

basic patterns. While many of these horses will end up classified as

toveros, some with a combination of two or more overo patterns will

simply be called “overos”. The important thing to remember is that all

four patterns are the result of separate genes, and that when several

are inherited by the same horse, identifying just which patterns are

involved can be difficult.

Like many combination pintos, this tovero - a combination of tobiano and

sabino overo - is predominantly white.

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