Okay so for my college equine class I'm going to do a project/PowerPoint over what genes make what white.
So, can somebody point me in a direction on what the sabino, splash, frame, Tobiano (am I missing any?) look like?
I'm also going to use pictures for examples.
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I could go on an on about his topic so I will try to stay on track as much as possible :) I know a lot about these kinds of genetics but I am not an expert! I can give you a good outline though!
I'm not sure what you mean by "what genes make what white" because white is not really a color
more like lack
thereof. To truely understand the different coat patterns (overo, tobiano, sabino etc . . .) you need to understand what causes the disturbance in melanin.
The appearance of "white" in pinto/paint horses is related to genetic mutation called Leucism
. UNlike albino, which most people are aware of, does not exist in the equine world, rather a specimen has not yet been reported. Leucism
, however, is similar to albino in that albinism is solely a lack in melanin - black and brown pigments (eumelanin) - for both mammals and reptiles; where leucism
is a lack in all
melanin pigments in every
species - the gene behaves the same in every animal.
In horses, there are two main melanin pigments: eumelanin
a.k.a. agouti (bay/black) and phaeomelanin
As a side note, these genetic phenomena which are overwhelmingly present in equine, show up in other species too, however, affect such species differently. For instance, for whatever reason there is a link between medecine hat paints (another form of leucism) and deafness, however, in ball pythons (python regius
there are no noticeable defects linked between animal and mutation.
Here is an example of a leucistic ball python (a pinto
and here is a leucistic deer (I'd say it looks similar to an overo pattern?) :
Next, another melanin modifier, for lack of a better word, is the dominant white gene
, not to be confused with lethal white
(homozygous form of overo) - there are eleven different forms of D. white!
Here is an D. white thoroughabred stallion:
NOW for the actual variety of inheritable patterns: this is a hotly debated issue between horse breeders and scientists. For example, Quarter horses are supposed to SOLID, however, every now and then a foal pops out with a belly spot and to my knowldege would make the foal unregisterable as ONLY a QH but would have to be double registered as QH/PAINT. (maybe some breeders can help here?). But anyway, the parents of this foal would more than likely be carrying some form of the sabino gene.
Hence, we see paints with "roaning" not to be confused with a "red roan" or "blue roan" (different kind of roan), example:
Some horses who carry the sabino gene (heterozygous) will display this roaning of white hairs.
I know I am forgetting something, or a lot, so please message me of w/e if you ned moe clarity - I can help :)