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Observations on Splashed White and Deafness

Daylene Alford February 17, 2012 February 17, 2012

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I have seen several people wonder (not just here but in other places) if deafness in splash is associated with SW2 rather than SW1. My gut feeling is telling me no, it's to wide spread for that, but it has got me curious. If anyone knows of deaf horses who have tested as only having SW1 please post.

TheRedHayflinger Fri, 02/17/2012 - 15:30

I wish a friend still had her mini that was deaf...I'd test him! LOL He looked like an average homozygous splash with no other patterns.

Anyway..was digging around...maybe they could put feelers out for you for horses that have been tested?

http://www.deafhorse.com/ and they are on facebook as well: http://www.facebook.com/pages/Deaf-Hors… if that works..if not, just put in Deaf Horse Association

Monsterpony Fri, 02/17/2012 - 20:45

I know of at least one deaf splashed white Icelandic so if SW2 is really isolated to the Gunner lines, then it is definitely not only SW2 causing the deafness.

rabbitsfizz Sat, 02/18/2012 - 11:01

I think people are placing way too much importance on the possibility of there only being three mutations of Splash.
I am almost certain there are many more, as with Sabino.
Thus all theories about Splash and deafness and Splash and blue eye inheritance are going to be pretty pointless.....

JNFerrigno Sun, 02/19/2012 - 09:12

Gowers book talked about a line of Splashed White horses in Australia which had a high occurring of deafness I believe. I do not know if they were APHA imports, or something else. Don't have the book with me, but that's the first time I ever heard of it.

Songcatcher Sun, 02/19/2012 - 14:29

[quote=rabbitsfizz]I think people are placing way too much importance on the possibility of there only being three mutations of Splash.
I am almost certain there are many more, as with Sabino.
Thus all theories about Splash and deafness and Splash and blue eye inheritance are going to be pretty pointless.....[/quote]

Jane, as you know, I have tremendous respect for your knowledge and opinions on color genetics. I'm curious to know what you base your opinion that there are many more mutations on.

So far, there have been a handful of horses that we have considered to be minimally marked Splash, who test negative.

I think we (through discussion on this board and others) fairly accurately determined that Splash is heterozygous form will result in fairly minimal markings, while in homozygous form will result in some rather wild expression. Thus I do think discussions of these theories can bring about more understanding.

IF we come up with a wildly marked, obvious Splash, that tests negative, I think your opinion will be proven true. But, so far we have not seen that. With Sabino, we have seen many obvious Sabino horses that test negative for SB1. I think we need to see MANY more test results from Splash before we can come to a conclusion.

Ameria Park Mi… Wed, 02/22/2012 - 19:55

My splash white mini colt isnt completley deaf but he is hearing impaired, i have sent his hair samples in to be tested for splash...sire is a true splash, dam is a minimal...

Danni Thu, 02/23/2012 - 03:22

[quote=Songcatcher]IF we come up with a wildly marked, obvious Splash, that tests negative, I think your opinion will be proven true. But, so far we have not seen that. With Sabino, we have seen many obvious Sabino horses that test negative for SB1. I think we need to see MANY more test results from Splash before we can come to a conclusion.[/quote]

I put some on this thread I think look splash

http://colorgenetics.info/equine/forum/…

rodeoratdogs Mon, 03/19/2012 - 20:38

I just met a girl on another forum who pm'd me about how to get her colt tested for Splash, she's pretty sure he's deaf. She is getting the forms ready to send in to UC Davis. She sent me some pics and gave me permission to post. He is 6 months old now.

Daylene Alford Tue, 03/20/2012 - 20:43

Oh I can't wait to see how he tests. Something about how ragged the edges of the face and body white makes me wonder if he may be frame rather than or in addition to splash.

Threnody Wed, 03/21/2012 - 08:36

I definitely see frame. It seems really lacy so I'm thinking sabino might be in there too. Since he's deaf I'm betting on SW.

Oh! Do we know of any deaf [u]heterozygous [/u]splash horses? I know it's most common in those that appear homozygous.

rodeoratdogs Wed, 03/21/2012 - 08:52

I see frame too, however she is not testing for frame because she is not planning on breeding. She rescued the Dam and his name is BOGO because she didn't know she was bred so it was buy one get one free :D .
She was trying to get some help on the horse rescue forum on trying to figure what was going on with his hearing and saw my post about SW and pm'd me on how to get him tested. Last time I talked to her she was trying to get a hold of UC Davis because she does not have the stallion info and was wondering if that mattered, do any of you know?

Threnody Thu, 03/22/2012 - 10:58

Since SW is a direct test it doesn't need info on the parents to help determine genotype like the zygousity marker tests for dun and roan do.

So nope. You can just send the samples in.

rodeoratdogs Thu, 03/22/2012 - 11:09

Oh good, well she did find the sire info now but she already sent the sample in. She said the sire was Zips dirty outlaw, I tried but couldn't find him on allbreed. The Dam is Coosa bred.

rodeoratdogs Fri, 03/30/2012 - 08:33

[quote=rodeoratdogs]I just met a girl on another forum who pm'd me about how to get her colt tested for Splash, she's pretty sure he's deaf. She is getting the forms ready to send in to UC Davis. She sent me some pics and gave me permission to post. He is 6 months old now.[/quote]

Ok the owner of this colt just got her test's back, and he was negative for all 3 mutations of SW,so now she doesn't know where the his deafness come's from and is fustrated. Does this mean that he has a unidetified mutation of Splash?? Also she would like some help with the sire's side of pedigree the Sire is Zips dirty outlaw (Paint) and the Dam is Coos it up (QH). I'm not a member of the Paint horse association anymore and I can't find the sire on all breed.

Daylene Alford Fri, 03/30/2012 - 09:25

If, as has been often theorized, deafness is caused by a lack of pigment in the inner ear deafness could be caused by any white pattern that removes color in that area of the ear, not just by splashed white.

rodeoratdogs Fri, 03/30/2012 - 09:43

[quote=admin]If, as has been often theorized, deafness is caused by a lack of pigment in the inner ear deafness could be caused by any white pattern that removes color in that area of the ear, not just by splashed white.[/quote]

Yes, this was I was wondering as well, just the lack of pigment in the inner ear. Although his one front high white looks very "splash" to me.

Monsterpony Fri, 03/30/2012 - 14:35

Given the proposed location of the splash mutations (MITF), I would be surprised if there [i]weren't[/i] more than three mutations at work. MITF is a known to be a common location of white mutations in several other breeds.

rodeoratdogs Fri, 03/30/2012 - 22:11

Here is his actual test results, she just forwarded them to me....

Coat Color results for BOGO(DT30074):
>
> Splashed White SW-1 Result:
> N/N - No copies of SW-1 mutation.
>
> Splashed White SW-2 Result:
> N/N - No copies of SW-2 mutation.
>
> Splashed White SW-3 Result:
> N/N - No copies of SW-3 mutation.
>

Monsterpony, can you explain(MITF)in a little more detail and what are some of the other white mutations in the other breeds you are talking about? I know what you mean by location but that's about it.

Monsterpony Sat, 03/31/2012 - 07:41

Sorry, I meant species, not breeds. MITF is the name of a locus found in cats, dogs (I think), rats, mice and a few other species that mutations are known to cause several white spotting patterns and blue/pink eyes. It is a likely candidate for splash based on phenotype and I know the researchers were focusing on it awhile ago when looking into splash.

rodeoratdogs Sat, 03/31/2012 - 09:53

Oh ok, well one of the researcher's I spoke to at Animal genetics was quite interested in the relationship between lack of pigment in the inner ear causing deafness in different species as well, like Dalmation dogs and Paint horses.

Spotting Girl Tue, 04/17/2012 - 16:17

Hi, as the research about splashed mutations is still going on, you have the chance to send hair samples to Berne Switzerland. About 30 hair roots are needed. There is still the possibility, that in MITF or PAX3 can appear additional mutations in horses looking splashed.
If you are interested (or the owner, even better), visit the homepage http://www.genetics.unibe.ch/content/la…

best regards