Appaloosa


ColorShiftTypical

I have been busy with work on the upcoming book, but I wanted to share some good examples of the color shifting found in some horses with the Leopard Complex (Lp) mutation. Appaloosa shows are less common than Paint shows in this area, so I was glad when one was scheduled for the Garrison Arena in nearby Clemson, South Carolina on a weekend that I was free to attend.

The mare above is a shade of warm pewter gray that is very common in appaloosas. I would expect her to test black (E_aa) and negative for dilutions, just as my mare does. What is interesting is that not all black appaloosas end up looking like this. At the same show, there was a jet black leopard. Just why the color shifts on some, but not all, is not yet known, though it does not seem necessary for there to be a true dilution gene present for it to occur.

SnowcapFeet

The change in this guy is more subtle. He might be mistaken for a sun-faded black horse, but look closely at his lower legs. They do not look black, nor do they have the reddish or  yellowish tones that are more typical of sunburnt hair. Instead they have a dark chocolate tone. In my experience, that “off” color is even more noticeable in person – especially in natural light.

That brings me to the last horse. This mare may well be chestnut, but I would not be entirely surprised if she was in fact black-based. Her odd tone is present to an extent in this photo, but it was more obvious in person. She would certainly be an interesting one to test.

BaseColorQuestion

I would also add that all three of these horses are probably homozygous, and the last two images are good shots to show how homozygous horses have shell-colored hooves on their unmarked feet. My own mare is heterozygous, and as her images (linked above) show she is actually more diluted in color than the first two of these. Whatever causes the shifting, it does not seem to be influenced by whether or not the horse is homozygous for Lp.

(Clicking on the last two images will take you to larger versions.)

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Thumper2013

The official Leopard Complex test is now available for $25 from UC Davis. A paper detailing the causative mutation is expected in the near future. Congratulations to Sheila Archer, Dr. Rebecca Bellone and the Appaloosa Project on the discovery!

For more information on Leopard Complex, including some older posts that explain how it works together with patterning genes to produce the variety of appaloosa coat patterns, can be found by clicking on “Appaloosa” under the Categories menu to the right of this page.

In the comments section of the last post, some posters noted the similarity of the white areas to fleabitten grey. That is not an uncommon thing with appaloosa patterns. Although it is easiest to think of the action of Leopard Complex (Lp) as a form of progressive roaning, where white hairs gradually replace the colored ones to form what American horsemen call varnish roan, in actual practice the process can go both directions. That is, it can add white hairs to lighten the coat, and it can add concentrated bits of color to speckle the coat. These darker hairs are sometimes called repigmented spots because they typically occur after the coat has already begun to roan out, or in an area that previously had white patterning.

The varnish roan mare at the top of this post is a very good example. I have run photos of Freckles before for the series of posts on appaloosa mottling. I have easy access to her, since she shares a pasture with my own appaloosa pony, Sprinkles. This particular image shows her coloring from four years ago, when the lightest parts of coat were an even mixture of white and color. At that time, had she not had such pronounced varnish markings on her body, and a sprinkling of dark spots on her hips, she might easily have been mistaken for a pale grey. (This particular photo was taken in early May, so she had not fully shed out for the summer and was just a shade or two darker than she would be in summer coat.)

Here is Freckles as she appears now.

Each year she has gotten more pronounced dark ticking in the roaned areas of her coat, even as she gets lighter in the areas that were colored. This lighter ticking is most noticeable if you compare the right hind leg in the two pictures. The repigmented specks first began to appear on her shoulder, but over time they have spread across most of her body.

This close-up of her topline shows just how closely this resembles fleabitten grey. In fact, if I use Photoshop to remove the hip spots and what remains of her varnish marks, the resemblance to a true fleabitten grey is quite striking.

I suspect some type of repigmenting is part of what was going on with the roaned areas on the horse in the previous post. With Freckles, the flecking ties visually with what is already going on with her coat, so it looks less jarring. With the horse from the previous post, the odd transitions between his colored areas and the patterned areas make him look a bit like you pasted together parts of a bay appaloosa and a fleabitten grey.

 

While searching through some old binders, I found some photographs of an unusual Appaloosa pattern. I apologize for the rather poor quality of the images, which were taken in a poorly lit arena using a traditional (non-digital) camera. I’ve tried to bump up the brightness without losing too much in the way of detail. Apparently the horse was never in the right position to get a good side shot, which is a shame.

He caught my eye because of how abruptly his coat transitioned to the dark areas of his pattern. Also unusual was how rounded the edges were. This is especially visible on his face and neck.

 

The other unusual aspect of his pattern was the “bleached edge” effect on some of the roaned areas. You can see one on the bridge of his nose, both in the picture above and this one from the front.

 

The above shot also shows how the roaned areas appear to “pool” around the dark parts of his legs. Dark leg marks like this are pretty common on appaloosas, but the nature of the roaning, which looks a lot like fleabiting on a grey, all in discreet areas (with those oddly rounded edges) while areas of relatively clear bay remain is quite odd. If this was an artistic representation, and not a real horse, I would have said the artist needed to work on more realistic transitions  on the legs.

 

On both the leg shots, the faintly whiter outline on the roan areas can be seen. The blanket pattern on his hindquarters, though, is pretty normal. I’ll include a close shot, since the spots show a really nice contrast between the two different types of halo-spotting. The darkest spots have halos that are made up of a mix of white and colored hairs, while the centers are colored. The centermost spot has a halo created by dark skin underneath white hair. The center of that spot is a mix of white and colored hair, though elsewhere there are spots that have dark skin halos and purely colored hair centers.

These photos are probably close to 15 years old now, and I never did learn the name of the horse. If anyone recognizes him, please drop me a note. I’d love to be able to look into his background.

 

Nicole Jory shared a photo of her appaloosa pony, Jack, in the comments section of the post on snowflake patterns. I wanted to share him here because he is also a great example of color shifting on a bay appaloosa. His stockings hide it on the other three legs, but if you look closely at the left foreleg you can see the odd pewter color where the leg would normally be black. For some reason color shifting seems more common on black appaloosas than on bays, so I was happy to find such a good example.

He also has what I call an “occluding spot” over what would probably have been a bald face. Nicole suspected he was carrying a splash pattern, and I would tend to agree. Blue eyes and this type of face marking are very common in Appaloosas that trace back to Bright Eyes Brother, who is believed to have carried classic splash (SW1).

Jack will make a good jumping off point for the next set of posts about those occluding spots, which I hope to post later over the weekend.

Before I move on to badger faces, I wanted to share another unusual appaloosa from Steph’s files. She took these pictures at the 2012 Midwest Horse Fair, and I apologize for my less-than-perfect color corrections on them. This particular horse seemed intent on staying in the shade, so I had to play with the settings quite a bit so that his pattern was more visible.

Appaloosas that develop clusters of white hairs are often called snowflake appaloosas. Appaloosas that have larger, overlapping clusters of white hairs are sometimes called marbled. Horses that inherit both varnish roan (Leopard complex, or Lp) and grey seem particularly prone to developing the marbled pattern, but it also occurs on non-greys like this horse. Appaloosas like this tend to stand out from other appaloosa roans because they look more blotchy and contrasted, as the picture of this guy among other appaloosas shows.

If you look closely, this guy looks to have some kind of lacy, spotted hip blanket in addition to the marbling. The marbling also extends down the tailhead in fairly distinct round spots, which I thought was interesting. Like the moldy spots on yesterday’s horse, the whole effect looks very layered, with the darkest spots sitting on the topmost “layer” of the coat.

The marbling was not evenly spread across the coat, but concentrated on the forehand and on the chest in particular. That is more noticeable in this shot.

In some ways those areas are reminiscent of type of patterns seen on horses with the white fungal markings. There are also horses that develop a similar pattern that is not thought to be related to the appaloosa patterns. You can find some of those, and some marbled appaloosas, on this Pintrest board.

Many appaloosas get some clustered spots of white as they roan. Here they are on the ears of my own near-leopard mare.

Around the same time she acquired white spots on her neck, chest and face, though those the existing roaning made them less noticeable than the ones on her ears.

It is not known why some appaloosas develop such an exaggerated version of this kind of clustered white spotting while most do not. Perhaps it is a modifier that redirects the roaning process, much like the Bend Or pattern appears to redirect the the sooty hairs into clusters on some horses. It is also possible that some of these horses may have some unrelated white spotting pattern, since breeders often assemble breeding groups that contain similar-looking colors that have a very different genetic cause.

My friend Steph Michaud sent some pictures from the 2012 Minnesota Horse Expo, which included the really loud chestnut leopard DREA Chief Fireagle. He is a great example of what the leopard pattern looks like on a horse without markings. Appaloosas with white on the face and legs tend to have smaller spots with wider areas of white between them. This effect is sometimes called the Sabino Boost, because the sabino patterns appear to boost the amount of white in other patterns at the expense of the colored areas. Fireagle is particularly interesting because this type of loud patterning is more often seen on appaloosas with a bay or black base color than on those that are chestnut.

But I wanted to share the pictures because Fireagle has what are sometimes called “moldy spots”. Part of what makes the leopard pattern so desirable among appaloosa breeders is that unlike the other colored areas on an appaloosa, the spots do not roan out with age. A leopard is all spots, or nearly so, so the pattern does not change significantly over time. Leopards with moldy spots are the exception in that they develop random white dots inside some of their spots. The amount seems to vary, with some spots developing pinholes of white while others appear to roan out completely.

Because this is something that develops with age, it is sometimes mistaken for greying. Appaloosas that inherit the grey gene do lose their spots, but moldy spots are not caused by greying. Greying does other things to the appaloosa patterns which is worthy of a later post, but that will require tracking down some decent pictures. This, however, seems to be some variation on the normal actions of the Leopard Complex gene.

What I have always found interesting about moldy spots is that they highlight the separate nature of the clustered spots. Loud appaloosas have large patches of color that give the impression they were made by a number of individual spots that overlapped. Because only some of the spots develop “mold”, appaloosas with this trait show that the spots really are distinct entities. They may look like one large colored patch, but as far as the body is concerned they are truly layered. (This can be seen most clearly on Fireagle’s croup, where the different spots have faded in varying degrees.)

This ties in with the upcoming post about occluding spots and badger faces, which are other instances where colored areas behave like layers in a drawing. From there I’d like to get back to the discussion on Belton patterning with some of the images that have been sent to me since the initial post on that topic. That should also put things back on track for regular postings, so stay tuned!

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