Sometimes an Appaloosa's genetic recipe (genotype) does not match its appearance (phenotype) very well, and it ends up displaying significantly less white appaloosa patterning than is expected.
When this happens, geneticists assume there are factors at work that have partially restored normal pigmentation.
Some Appaloosa-patterned horses are born with moderate to large areas where their body has a revertant spot - a place where normal pigmentation is occurring, right in the middle of what would otherwise be affected by dense white patterning.
Classic roan is a distributed white pattern believed to be caused by a mutation at the KIT locus. It is referred to by the gene symbol Rn, for "roan".
No matter what the base colour, classic roan is easy to identify in most instances.Typically the pattern is visible after the shedding of the foal coat.
Some Appaloosas undergo dramatic changes in the appearance of their basecoat color.
Black pigment seems to be particularly susceptible to alteration, with black areas becoming red or coffee coloured, even a dilute taupe. This is often referred to as 'bronzing'.
The grey gene (G) is epistatic to all coat colours. This means it gradually and completely obscures Appaloosa patterning, including dark body spots and varnish marks.
This happens because over time the action of the grey gene causes a stop in the ability of pigment produced in the follicle to move up into coat hairs. As this process shuts down, spots fade and the horse eventually become white.
Here, we'll look at a variety of diluting genes and explore their effect on the basic coat colors.
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In this article, we'll explore the basic coat colours along with examples of their various shades and interaction with LP.
Click on any image to enlarge it and read more information.
