Did you see UC Davis now offers a Splash White Test?

[Lucky-C-Acres-Minis]

Splashed-White

Splashed white is a variable white spotting pattern characterized primarily by extremely large blaze, extended white markings in legs, variable white spotting in belly, and often blue eyes. Some, but not all, splashed white horses are also deaf. Recent research has identified 3 mutations – SW-1, SW-2 and SW-3 - that cause splashed white phenotypes in horses. SW-1 has been found in several breeds - Quarter Horse, Paint, Trakehner, Miniature Horse, Shetland Pony and Icelandic Horse – and may be present in other breeds as well. Horses homozygous for SW-1 (SW1/SW1) have been identified, which suggests that this mutation is not homozygous lethal. SW-2 and the rare SW-3 occur exclusively in certain lines of Quarter Horses and Paints. Based on predictions from other species, SW-2 and SW-3 may be homozygous lethals and thus matings of two horses that carry SW-2 or SW-3 should be avoided.

Horses that carry combinations of the splashed white mutations, tobiano or lethal white overo can display extensive white patterning or be white.

The VGL offers genetic tests for the splashed white mutations SW-1, SW-2 and SW-3. Results are reported as:

N/N No copies of SW-1 mutation

N/SW1 Horse has one copy of the SW-1 mutation

SW1/SW1 Horse has two copies of the SW-1 mutation

N/N No copies of SW-2 mutation

N/SW2 Horse has one copy of the SW-2 mutation

N/N No copies of SW-2 mutation

N/SW3 Horse has one copy of the SW-3 mutation

Research is still in progress. Information about the splashed white test will be updated.

 

[midnight star stables]

Wow!

That is great news! I have two that I will be testing soon!

:yeah

:yeah

 

[Lucky-C-Acres-Minis]

I think I'll be saving up and having Doc tested too

 

[Songcatcher]

Any word on the cost of these tests or a link to their site?

 

[supaspot]

great news !

 

[Mona]

Sorry, a little off-topic, but still related to color...is anyone aware of a seal brown test?? I saw an ad not long ago for a full sized horse stallion and they told all about his color test results and specifically mentioned was seal brown. I had not heard of that one in the past, so I wrote to the lady and asked about it, and she said that she had it done at Pet DNA in Arizona. Not sure if this is legit or not?? ANyone know anything about that?

 

[rabbitsfizz]

Yes, there is an At test but only one place offers it, and, as far as I know, still has not published??

It does seem to be pretty correct, though.

 

[Critterhugger]

WOW that is great news!!!

There is a lab in AZ that does the Seal Brown (At) testing. Here is a link...

http://www.petdnaservicesaz.com/Equine.html

 

[Lucky-C-Acres-Minis]

Here's the link to all the tests/submission forms offered by UC Davis and their costs:

http://www.vgl.ucdavis.edu/services/horse.php

 

[Charlotte]

There is a LOT of good information on this thread (links, etc.). Can it be archived somewhere easy to find? Thank you to all who have provided info.

 

[Lucky-C-Acres-Minis]

Also, for fun/interest, if you're planning on testing anyone for this, post a pic!

I'm going to test this boy, I know he is heterozygous tobiano, and OLW negative.. He has no face white except for a few (like 5-6) white hairs that I suspected to be sabino.. His eyes are brown.

I was pretty sure he was tobiano/sabino, BUT started suspecting splash when he was crossed on a black/bay solid mare (no white at all!) and produced this colt:

 

[Critterhugger]

On the UC Davis website it sounds like they test for all 3 splashed white marker types and for heterozygousity/homozygousity of each. That is pretty cool. I'll be curious if they can determine if a certain Splash marker is related to possible deafness in some splashed whites, and if it's in heterozygous and/or homozygous horses. I have a smoky grullo pinto mare that I want to get tested. She tested negative for LWO and negative for sabino 1. I have always suspected she has splash, and also some other type of sabino since she has some pattern roaning. If she tests positive I want to get her colt tested as well since I'll be keeping him as my main herd sire. It's such fantastic news they have a test for Splash.

 

[Little Hooves]

On the UC Davis website it sounds like they test for all 3 splashed white marker types and for heterozygousity/homozygousity of each. That is pretty cool. I'll be curious if they can determine if a certain Splash marker is related to possible deafness in some splashed whites, and if it's in heterozygous and/or homozygous horses. I have a smoky grullo pinto mare that I want to get tested. She tested negative for LWO and negative for sabino 1. I have always suspected she has splash, and also some other type of sabino since she has some pattern roaning. If she tests positive I want to get her colt tested as well since I'll be keeping him as my main herd sire. It's such fantastic news they have a test for Splash.

I also have a few horses that I'd like to test. My filly has roaning all over her, and a partial blue eye, but cannot be Sabino since she is homozygous for Tobiano (has to do with the KIT gene). It would be fun to find out these things!

 

[ohmt]

Why can't a horse be sabino while being homozygous for tobiano? I have had a couple homozygous for tobiano that I am positive are sabino. They have a LOT of sabino roaning.

 

[Songcatcher]

Why can't a horse be sabino while being homozygous for tobiano? I have had a couple homozygous for tobiano that I am positive are sabino. They have a LOT of sabino roaning.

Me too. I have heard that a true Roan can not be homozygous for Tobiano (due to coming from the same location), but not Sabino.

 

[Little Hooves]

Me too. I have heard that a true Roan can not be homozygous for Tobiano (due to coming from the same location), but not Sabino.

I will have to check my facts, but from what I remember, Roan, Tobiano, and Sabino share the KIT gene, which means the only likelihood for the appearance of the roaning on a homozygous Tobiano is to come from the splash gene.

But I will double check today to find out if Sabino shares the KIT gene with Roan and Tobiano, or if I'm remembering wrong, but I do believe there were 3 genes that shared it. My resource (hubby's computer with downloaded PDF) is out of town with the hubby

I'll ask him to check.

 

[ohmt]

That is very interesting-i am behind on my genetics reading! Had not heard about roan and tobiano either.

Here is a stallion I had that was homozygous for tobiano and had a lot of sabino roaning (you can see it on his back here-he was young in these pictures-he has a LOT more sabino roaning now, especially on his face):

 

[Little Hooves]

Dominant white, roan, sabino-1 and tobiano have all been mapped to the KITgene region on Chromosome 3.

equine-genetics.com

... some of what we think of as separate colors occur on the same actual gene. They are different mutations, but they share a location. In the case of Sabino1, the mutation occurred on a gene known as KIT. Other mutations found on or very close to KIT are tobiano, true roan and dominant white. This might not seem important until you remember that an animal has two copies of any given gene, one from each parent. It can only give one to any individual offspring. If a horse only has two KIT genes, then it can only carry two mutations – one on each copy of the gene. That means you only have two slots to fill with KIT mutations. A horse could be homozygous for tobiano, but then he could not also carry Sabino1. His two KIT slots are already filled.

equinetapestry.com/category/sabino/

 

[ohmt]

So it is only Sabino1 then that can not be present if a horse is homozygous tobiano, right? But it is believed that there are many other forms of sabino-I don't even bother with the one sabino test that is available. Like the stallion I posted a picture of-he is homozygous for tobiano and very obviously sabino as well, just must not be Sabino1. Correct me if I'm wrong, I am behind on my genetics reading!

 

[Little Hooves]

So it is only Sabino1 then that can not be present if a horse is homozygous tobiano, right? But it is believed that there are many other forms of sabino-I don't even bother with the one sabino test that is available. Like the stallion I posted a picture of-he is homozygous for tobiano and very obviously sabino as well, just must not be Sabino1. Correct me if I'm wrong, I am behind on my genetics reading!

You're probably right, but it may not be "Sabino" at all and could be unidentified. I do see a lot of tobianos with snips or chin white that also have the roaning. To me, it seems this is also connected to blue eyes/partial blue eyes - I never really thought about it much, but I'm starting to research it more. There is obviously another gene in the mix, or perhaps tobiano creates more variation than we once thought and face white and roaning are also part of the tobiano mutation. My bay pinto filly has a white snip, and the "sabino roaning" and a partial blue eye. If it really is another color gene, it is not on the KIT gene.