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Confused Deviant

I have [url=]this[/url] photo of my horse Bandit on Deviant Art, listing him as a tobiano/splash/sabino. You can read through the comments, but there was a lot about white patterns. Anyway, I just received this message [quote]Actually, tobiano does put white on the face. Tobiano will cause normal facial white markings, ie, blaze, star, stripe, snip, and any combination thereof that is a plain non paint modified facial marking. Also, Overo is not simply anything that isn't tobiano. Overo is specifically paint markings that do not under any circumstances cross over the top line. It has a place at the O locus for the Overo marking and the only time it can cross over the top line is when it is combined with dominant tobiano traits at the T locus which creates a Tovero. Splash, Sabino, and Frame are not overo, they can be confused as Overo because Spash and Frame are almost never cross the topline as the white looks as if it has been painted on from the bottom up instead of drizzled over the top like Tobianos and some sabinos. However, Sabino can be quite tricky so my guess is he's likely jsut a tobiano, but without a gene test, you won't know exactly his genes. Most you cannot confirm without a gene test in the first place.[/quote] And it is things like this that keep LWOS an all too common occurance. My response: [quote]I'm sorry, but I will have to disagree with you. First of all, Frame and Lethal White Overo, which is often called solely, but erroneously, "overo," was mapped to a missence mutation at the EDNRB gene, not the O locus. It is only seen in heterozygous horses as the homozygous form is lethal. Heterozygotes can express a pattern that exhibits anywhere from no white at all to white that does (though rarely) cross the horse's topline. Calling it "overo" is very misleading because the APHA will register splash white and sabino patterns as overo as well, hence the reason I call it a catch-all term that does not specify the actual pattern. Tobiano has been mapped to the KIT locus as a large chromosomal inversion, not the T gene, and also has a very wide range of expression. Tobiano, in its most minimal expression, can be seen as solely just white socks on the hindlegs, which obviously does not cross the topline. Tobiano often does not cross the topline even when expressed more. Tobiano does not put white on the face, rather it can restrict the amount of white. Tobiano and frame, especially when combined with splash white or one of the sabino genes can be confused with each other easily. I understand what you are saying about sabino as it tends, like overo, a catch-all term. With only one form of sabino mapped, the rest are hypothetical. The reason I called Bandit tobiano/sabino/splash (he could also carry frame) is based on multiple components. He is obviously tobiano, based on the vertical marking pattern, chest and flank shield and white tailhead. The sabino and splash are guessed based on the heavy face white that falls off the side of his face with solid around the eyes. Based on APHA registration, he would be a "Tovero," but I personally am disinclined to use APHA as a reference as they are notorious for inaccuracies in their registries. I do not use the term overo and its highly fallible definition as it is too inaccurate and causes much confusion, which can lead to devastating results. You will notice that I added the ? because I have not tested him to be positive, but I have no reason to test him as he is gelded and I don't need to know what genes he would pass on.[/quote]

NZ Appaloosas Tue, 03/10/2009 - 19:03

OMG, how can anyone call that a "normal" facial marking? It widens above the eyes, narrows between the eyes and flares out again, trying to slide off the face--typical spalsh/sabino "fighting".


Monsterpony Tue, 03/10/2009 - 19:10

I generally try to be less blunt, but when they started calling overo a gene that had been mapped and then talking about frame as something completely different, in my head I said (as my sister would put it) "Oh no you di-int!"

NZ Appaloosas Tue, 03/10/2009 - 20:30

Okay, now the two of you get to fight over who gets to pay for cleaning my laptop AND explaining to two barristers why I just spat hot tea all over the place!!!!!!!!!!!!


Paintlover Tue, 03/10/2009 - 20:51

[quote="Sara"]In your head did you also do the moves that go along with that? :))[/quote]

That is so funny because I envisioned the same thing!!! :rofl

Not exactly sure where this person got there info?? I had never even heard that before!! People lumping splash, sabino, and frame together as overo I understand when they don't know any different but Overo as a fourth gene. :shock:

critterkeeper Fri, 03/13/2009 - 12:58

NZ - you tea, me coffee (P.S. - blowdryers work on keyboards).

MP - go get 'em lady. :hammer I wonder if this person is teaching equine genetics in Ohio? (jk Indian)

NZ Appaloosas Sun, 03/15/2009 - 22:00

[quote="critterkeeper"]NZ - you tea, me coffee (P.S. - blowdryers work on keyboards).


It was more the having to explain things to the two barristers... :oops: :laugh1 :rofl