Tag Archives | roan patches on tobianos

Requested images

BlazedTobiano

One of the commenters asked for images of the other side of this horse, which appeared in the original tobiano marking post. I was fortunate to get quite a few good images of him. (If only all the classes were held in this particular arena, which is situated just right relative to the morning sun!)

TobianoFace7 copy

You can almost see the random roan patch on his left hip in the side shot, but it is more visible in this one taken from behind.



I liked the way his tail was variegated, so I got a number of shots of it. (Be warned, however, that because Paint Horses can use tail switches, colors on tails may not always be natural to that horse.)

TobianoFace6

This was a good shot for showing how the color on the head of a tobiano spreads downward towards the jaw, so that in individuals with more white, there is a narrow “V” at the throat where the color on the two sides merge. I am working on a post that goes into more detail about this, and about how color tends to travel on the faces of tobianos, since that is relevant to the discussion on tobiano face white.

I am also trying to pull together some pieces to expand on some of the unusual colors that have appeared in recent posts. I apologize that we have wandered off in several different directions, but threads tend to come back around eventually. Fortunately you are all pretty tolerant when we take the more erratic, meandering path!

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More roaning and ticking

Dexter1

Another kind of roaning that is often attributed to the sabino gene is the kind seen on this chestnut tobiano pony, Dexter. This has a softer look than the “laced” edges that Dexter’s sabino-tobiano stablemate Splash has.

What makes Dexter unusual, though, is that he has a solid face.

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He does have a white patch on one side of his chin which does not reach up to his lower lip, which can just barely be seen in this picture. (Because it is really under his chin it is hard to get a good image.)

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It may be that modifiers are suppressing the sabino gene to such an extent that his chin patch is all that is left. It’s also possible that this type of roaning is itself some kind of modifier, and that the white on his chin is unrelated. The commonly accepted rule is that tobiano by itself does not create white on the face, though both myself and others have had reason to question the absolute nature of that rule.  (Because that statement is nigh upon heresy to many horse color enthusiasts, elaborating on that probably merits a separate blog post at a later date.)

But it is pretty clear that this is different from true roan. Here is what true roan, when combined with tobiano, looks like. (The photo comes from Reasontobecrazy stock photography.)

stock___dark_red_roan_tobiano2_by_reasontobecrazy-d46eo0z3

Here is a close-up of another roan tobiano.

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Notice how the roaning is evenly distributed across the spots. Now compare that to a close-up of Dexter’s hip.

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It’s also different from the roan patches that are sometimes seen on tobianos, particularly homozygous tobianos like the one below. Those tend to be rather random, whereas the roaning on horses like Dexter are concentrated around the borders of the dark patches.

Here is a close-up of roughly the same area on Dexter.

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Here is another horse showing the same kind of softly roan edges,  although he has the white face markings that Dexter lacks. (The photo comes from Citron Vert Stock.)

tobiano_pony_by_citronvertstock-d3er0932

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Sabino influence – lacing the edges

The post from yesterday talked about the tendency of sabino to break dark areas of a pattern into smaller, more numerous pieces. The other thing that sabino tends to do is degrade the edges of the other pattern by making them lacey, roany or ragged.

Using the pattern from yesterday, here is an example of how that might look.

The tobiano pattern is still plainly visible, but the edges have become lacy and irregular.  Looking carefully, it’s obvious that this isn’t an overlay of a loud sabino pattern because the irregular areas are concentrated along the edge of what would be a tobiano pattern, instead of the areas associated with sabino.

Here is a horse with this type of sabino influence.

SabLace3

Notice that while he does have lacey markings along the girth – something you could expect on a sabino – the primary direction is upward toward the withers, following the line his tobiano pattern might take.  Meanwhile, there is almost no white under that front armpit or along the belly, which would be the most likely place to look for white on a purely sabino horse.  So the sabino instruction to “add lacey white” has been redirected to follow the pattern edges laid out by the tobiano gene.

And here is a more extreme version of lacing the edges.

SabLace4

The edges aren’t always lacy, though. Sometimes the edges take on more of a ragged, torn appearance. This horse is a good example of that.

RaggedEdges

(I apologize for the “headless horsewoman”. Since I am only taking pictures for my own reference, I often zoom in to get the horse big in the frame, which means a lop a lot of people off!)

Laced edges are something not only seen when sabino is paired with tobiano, but other patterns as well.  This horse is most likely carrying sabino and frame.

SabLace2

The softened, roany look to the marking on her side is very typical of sabino, yet all four legs are unmarked.  Although not as obvious in this picture, the marking did not extend under the belly either.  The appearance is that of a purely frame pattern with just the outline altered.

And here is a splash overo with laced edges. Notice how the sabino patterning follows the edge here, too.

SabLace1

I should caveat this post with one warning for painters, though. It is true that complex, ragged edges are associated with the presence of sabino and that horses without it have simpler patterns. The edges are more even, but it should be said that even on simple tobianos – and simple splash overos, the other “smooth” edged pattern – that the edges can still have irregularities. Here is a close-up of the brown tobiano mare from the previous post.

UnevenEdge

The overall impression is still that of a large, fairly even patch – but the up-close look will often show this kind of edge.  (I’ll talk about her roaning in a later post, because that’s not necessarily a sabino trait either!)

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