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summary of sw tests

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colorfan
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summary of sw tests
Let me see if I have this right So far there are three tests for types of Splashed white. There is thought to be a white suppressor gene that expresses itself as ermine spots. Do they have to be spots? Could they be a very thin band of color on the coronet band? I read, perhaps on horse grooming that Quarter Horses cant be tobiano? Is that more because QH don't permit 'pinto' rather than the gene doesn't exist within the breed? I have gathered there is a theory that there is another white factor at work in some horses, is that right? I just read on another forum that only Tobiano can be homozygous. Overo can't be because it results in LW. Shouldn't that statement read that homozygous frame will result in LW but splash or sabino can be homozygous? Guess this last one is more a tobiano question than sw.
Songcatcher
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Correct on Splash (at least

Correct on Splash (at least for now). SW1, SW2, and SW3. So far, SW1 seems to be by far the most common.

I can't answer regarding the ermine spots. I'm sure some one else will. Also, I am not a Quarter Horse person so I will leave that to someone else.

Another White pattern gene is Dominant White, of which there are several mutations.

You are correct that FRAME Overo cannot be homozygous, or the foal will die within hours or a couple of days. Sabino and SW1 can be and often are homozygous. Early theories are that SW2 and SW3 are likely embryonic lethal.

Freeland Nash Valliant, OK 74764 www.songcatcherranch.webs.com

Katie
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The tobiano gene does not

The tobiano gene does not exist in the QH breed. So no, QHs cannot be tobiano.

colorfan
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Katie wrote:The tobiano gene

The tobiano gene does not exist in the QH breed. So no, QHs cannot be tobiano.

Really? How can this be?

When I ride I feel His pleasure.

Daylene Alford
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I believe it is because

I believe it is because Tobiano is so much harder to hide than the other white patterns and is also more recognizable. It was easier for early QH breeders to weed out.

rabbitsfizz
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No Tobiano in Arabs, either,

No Tobiano in Arabs, either, or TBs (yet).
I am still positive that the current SW tests are about as much use as Sab1 ymwhisle

website: please come and visit... http://www.shadowplayminihorses.co.uk/

Threnody
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Thankfully SW doesn't seem to

Thankfully SW doesn't seem to mutate as much as KIT does. :lol: I have at least 6 new unisolated DW mutations in my color files from TBs alone from the past half century. 7 if you count Catch A Bird's roan mutation along with the other KITs.

colorfan
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How does kit differ form the

How does kit differ form the the other mutations like SW? :-?

When I ride I feel His pleasure.

Threnody
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KIT is officially the most

KIT is officially the most easily mutated gene in horses according to researchers. It also holds that title in a few other species but I can't remember them off the top of my head. This basically means that KIT likely has a much larger amount of mutations than we have even observed. Hence why Sabino1 testing doesn't do much for people wanting to find out if their horse has sabino. There are many many mutations of sabino, but only a test for 1 that is only found in a handful of breeds. There are possibly hundreds of KIT mutations. And at least 3 different roan mutations (Common classic roan, roan in European drafts, and Catch A Bird roan in TBs) which are also mutations on KIT.

tjuri
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...and don't forget to

...and don't forget to mention DW for sure and possibly rabicano roan... ymwhisle

Threnody
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^ Lol, yes very true. I

^ Lol, yes very true.

I love the amount of visual variation all the KIT mutations have too. KIT is also a very large locus so there is more room for mutations to happen. SW likely isn't going to have nearly as many mutations as KIT and so far all of the SW mutations found look the same.

colorfan
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Thank you, this really helps

Thank you, this really helps but....is kit like agouti, just many more variations?

Is locus the location on the chromosome?

When I ride I feel His pleasure.

Monsterpony
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This is the best summary of

This is the best summary of KIT and its mutations I have found. It is outdated just due to researchers having found more mutations since it was written, but it is still incredibly helpful.

http://www.duncentralstation.com/PDF/KIT...

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pandemonium