Archive | Appaloosa

More examples of appaloosa color shifting

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.

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Leopard Complex (Lp) test now available

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.

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Repigmentation spots

Freckles2008

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.

Freckles2012

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.

FrecklesCU

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.

FrecklesFleabites

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.

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