# What genes make what white?



## MangoRoX87 (Oct 19, 2009)

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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## smguidotti (Jul 31, 2012)

MangoRoX87 said:


> 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 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* (non-agouti/chestnut). 

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_ python lol) 


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


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## TexanFreedom (Apr 2, 2012)

I like what the above has said, and like stated, you missed DW- which isn't always a wholly or majority white horse- ex. the whole Puchilingui line [<3] and I think there is even a whole other separate line of DW TB's...? 

I have lots of pictures, but if you need the sources/references or permission to use, I don't have any, but it wouldn't be that hard, given the cool google image URL search tool :3


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## Poseidon (Oct 1, 2010)

In addition to Dominant White's maximum expression causing an entirely white horse, like what's posted above, sabino's maximum expression also causes a total white. Maximum sabinos have dark eyes if there is not another gene present. 









Splash will also cause an entirely white horse in the right combination. 

Can't Hear Guns, if I remember correctly, is positive for all three mutations of Splash currently testable. I don't remember her zygosity of any of them though. She's entirely white and deaf (hence her name ). Calla is genetically a bay under the white although she appears to be a double cream dilute with her pink skin and blue eyes. 









Frame in its homozygous form causes a nearly entirely white (some do have small spots of color) or entirely white foal, for what it's worth. That foal will die, but it's still a white horse. 
This filly was a LWOS foal










smguidotti said:


> 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?).


Cropout Quarter Horses can only be registered as APHA if they have one APHA parent. The rule used to be that a QH with too much white would be sent to the APHA because the desired look for QHs is solid, although QHs carry frame, sabino, and splash.


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## Poseidon (Oct 1, 2010)

Hopefully these help and you can educate people more. One of my professors last year used a very old, outdated book and taught that grey and white are only different because greys have dark skin and whites have pink skin. ..This is coming from a textbook that also said grays are ALWAYS born black.


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## smguidotti (Jul 31, 2012)

Poseidon said:


> Hopefully these help and you can educate people more. One of my professors last year used a very old, outdated book and taught that grey and white are only different because greys have dark skin and whites have pink skin. ..This is coming from a textbook that also said grays are ALWAYS born black.


Thanks for clearing out the "crop out" issue

Funny you mention that issue with your professor - In my sophomore year (*2009*) my biology teacher was under the impression that when you mix a "white" horse with a black horse you get a piebald . . . lol I raised my hand and said, "Mrs. Kyle, that is impossible, the horse depicted in the book is clearly _gray_ and mixing two solid coat colors doesn't create an animal expressing piebaldism unless it is carrying a gene which causes such a mutation." She also believed that all "white" animals were albino . . . She didn't believe me and mocked me in front of the whole class. Later that night I sent her an email with over ten sources proving I was right and that she was teaching out-dated materiel. 

Since then I always wondered what else in incorrect in our school books that cost us an arma and a leg :evil:

Needless to say, her and I didn't get along very well lol


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## Poseidon (Oct 1, 2010)

smguidotti said:


> Thanks for clearing out the "crop out" issue
> 
> Funny you mention that issue with your professor - In my sophomore year (*2009*) my biology teacher was under the impression that when you mix a "white" horse with a black horse you get a piebald . . . lol I raised my hand and said, "Mrs. Kyle, that is impossible, the horse depicted in the book is clearly _gray_ and mixing two solid coat colors doesn't create an animal expressing piebaldism unless it is carrying a gene which causes such a mutation." She also believed that all "white" animals were albino . . . She didn't believe me and mocked me in front of the whole class. Later that night I sent her an email with over ten sources proving I was right and that she was teaching out-dated materiel.
> 
> ...


I shudder at piebald and skewbald for color descriptions. Ugh. My prof last year was really annoyed that I corrected her repeatedly in front of everyone also. Like her PowerPoint slide on bays. One horse was clearly a brown. "No, he's a dark bay." No, that horse is brown.


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## smguidotti (Jul 31, 2012)

Poseidon said:


> I shudder at piebald and skewbald for color descriptions. Ugh. My prof last year was really annoyed that I corrected her repeatedly in front of everyone also. Like her PowerPoint slide on bays. One horse was clearly a brown. "No, he's a dark bay." No, that horse is brown.


IT'S SO FRUSTRATING! Especially because the only other people who know these things are people like US so there is virtually no one else to complain to or look at for help! 

I mean, my teacher was an old woman who retired the next year (thank GOD) but I can't understand how this S*** still goes on in a college setting. It's like, when was the last time YOU checked YOUR SOURCES? 

[email protected]! 


I give up on life . . .


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## MangoRoX87 (Oct 19, 2009)

Thanks guys!!! VERY informative!! Lots of stuff that I will certainly use!!

I guess what I kind of meant...is like...when your looking at what I guess you would call a solid, how can you tell what gene is causing the shape of the white pattern (blazes, socks, etc)? Like I read that the sabino will make more symmetrical face markings, which doesn't make sense because theirs normaly have jagged edges when it's on their bodies...
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## MangoRoX87 (Oct 19, 2009)

Bumpity bump bump.
_Posted via Mobile Device_


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## smguidotti (Jul 31, 2012)

MangoRoX87 said:


> Thanks guys!!! VERY informative!! Lots of stuff that I will certainly use!!
> 
> I guess what I kind of meant...is like...when your looking at what I guess you would call a solid, how can you tell what gene is causing the shape of the white pattern (blazes, socks, etc)? Like I read that the sabino will make more symmetrical face markings, which doesn't make sense because theirs normaly have jagged edges when it's on their bodies...
> _Posted via Mobile Device_


Your welcome - I love when all the useless information I know actually helps someone lol 

Before I begin, there is not a whole lot of information out there that explains *exactly* what is going on with these genetic modifiers - most of the time the process is unclear. 

Looking at a solid bay, black or chestnut it's impossible to tell if it carries any mutation, _typically_ solid paints do not throw color. When you look at a solid "white" horse it is tricky to tell sometimes too, however, the eyes can help clue you in on what is going on (even on a solid agouti/non-agouti) . . .

Even with that said, there a number of diluents that will cause, for instance, blue eyes such as cremello. But every diluent tweaks the animal differently. As previously mentioned, some cause deafness or organ failure. 

"The Medicine Hat Paint has been documented as being produced by crossing frame overos on tobianos, sabinos on frame overos and sabinos on tobianos,"(APHA _Coat Color Guide_, 7). The problem, however, is that multiple copies of Paint genes produce more white on horses and some pairings may create lethal white foals. Additionally, like with ball pythons that mentioned earlier (the _pinto python_) there is also a blue eyed leucistic python much like a maximom white, blue-eyed paint/pinto horse, that is a "super form" of it's mutation - that is, it is _homozygous_ for such diluent. 









My speculation is that "maximum white" sabino horses are homozygous (the more copies of the gene, the more white you get) 

Markings can be very hard to define especially because the genes which cause the different patters seem to behave _co-dominately_. That is, when you mix tobiano + overo you may get a 3rd *phenotype* (visual representation) - a TOVERO, however, TOBIANO is the only *dominant* pattern.


My point with all this word garbadge is that you may be trying to label an animal as such but in actuality is actually visually dispalying two or more patterns/genes - this is why it is tricky to TRULLY answer your question. 

But for the easy ones I reccomend you take a look at the APHA's color guide: http://www.apha.com/forms/PDFFiles/guidebooks/07ColorGen.pdf

it explains what you are looking for as far as pattern differentiation is concerned . . . however, the information is still very superficial as far explaining WHY such things happen.

This website, in my opinion, gives good information on sabino patterns: sabino horses 

Hope this helps more . . . if you need help researching further or have a more specific question let me know - I enjoy reading up on this stuff 

-Sara


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## FeatheredFeet (Jan 27, 2010)

Please correct me if I'm wrong, but I was under the impression, that the word 'Tovero' went out years ago and true colour gurus, cannot abide the use of it. Don't know much about the APHA but those very knowledgeable in colour, are constantly stating on the net, of how often they get it wrong.

The best forum to really understand colour, is...

Forums | Equine Color Genetics

Lizzie


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## PaintHorseMares (Apr 19, 2008)

Many folks dislike using Tovero as well as Overo since they very broad, general classifications. As for the APHA, they are well aware of modern genetics but there is really no motivation for them to change from the old terms.
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## smguidotti (Jul 31, 2012)

I don't really keep up with the new classifications, I sort of gave up when the AQHA would not recognize a "Dunalino" (do they now?) but a I was browsing the APHA book I noticed a lot of inaccuracies such as calling a horse, "brown." BUt at least the APHA provides a CREDIBLE SOURCE for her powerpoint which is most important to professors, I would assume, because forums - although the information may be more accurate, however, forums are as credible as quoting _The Onion_.

It's too bad the registry will not recognize modern research on genetics - I think everybody would appreciate some consensus on these topics lol


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## Poseidon (Oct 1, 2010)

smguidotti said:


> BUt at least the APHA provides a CREDIBLE SOURCE for her powerpoint which is most important to professors, I would assume, because forums - although the information may be more accurate, however, forums are as credible as quoting _The Onion_.


I would quote people on this forum far before I would quote the APHA in terms of color knowledge. If it doesn't appear credible, I would track down a website that is far more updated on information and scientific fact than a registry. 

To the OP's original question:

Yes, you can tell some white patterns that are minimally expressed by "normal" markings.

My mare is positive for Frame (I have not tested her for sabino yet though). She only has a blaze and a small pastern. Her blaze is very top heavy and then spreads out over her nose. Frame loves top-heavy face white and will try to spread out over the face. Frame does not put white on the legs either.

Splash loves bottom heavy face markings and body markings, as if the horse was dipped in paint. For example, I would bet money that this gelding is heterozygous for one Splash mutation (Splash is an incomplete dominant, like cream, meaning one copy puts markings and two copies puts even more markings) and is entirely possible he also carries frame with the way his blaze spreads at the top.










Sabino likes chin white and symmetrical facial markings. It also likes jagged edges on what look like normal socks. Like this guy's socks:









Or long jagged "lightning bolt" streaks coming from the socks. I know a gelding whose hind socks look like that. I wish I had a picture.. 

Frame, splash, and sabino are much more likely to express very minimally than tobiano, though minimal tobiano can and does happen. There was a mare posted here not long ago that had a wonky blaze and threw a tobiano foal. Most minimal tobianos have their normal high leg white, but unlike splash, which is also likely to give high leg white, they have completely solid faces.


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## NdAppy (Apr 8, 2009)

smguidotti said:


> I don't really keep up with the new classifications, I sort of gave up when the AQHA would not recognize a "Dunalino" (do they now?) *but a I was browsing the APHA book I noticed a lot of inaccuracies such as calling a horse, "brown." *BUt at least the APHA provides a CREDIBLE SOURCE for her powerpoint which is most important to professors, I would assume, because forums - although the information may be more accurate, however, forums are as credible as quoting _The Onion_.
> 
> It's too bad the registry will not recognize modern research on genetics - I think everybody would appreciate some consensus on these topics lol


They are not inaccurate in calling a horse brown. Brown is a testable genetically different version of agouti.


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## smrobs (Jul 30, 2008)

I am not up to date on all the pinto genes as I don't have paint horses and I just haven't taken the time to really learn the different patterns.

I have been told that this horse (he was mine for a while) is a pretty standard representation of tobiano. I'll depend on others who are more educated in the patterns to verify that though. Please forgive the really crappy photos, the only ones I have of him without a saddle are even worse quality. But, he had no white markings where the saddle sat.


















This filly was basically the definition of Sabino. She did not carry a "roan" gene, all that roaning is caused by the sabino gene...along with the splotchy white markings on her sides/neck/hips and the jagged edges to her face and leg markings.


















And, I strongly suspect that this filly is likely carrying Splash, what with the high whites, broad face stripe, and the belly spot being the only white she has. She's not been tested though and I probably never will as she will never be bred. If I do, it will only be for my own curiosity. I'll be honest though, I'm not sure if all pinto genes will create a blue eye or if that particular trait is only seen with _some_ genes.


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## smguidotti (Jul 31, 2012)

Poseidon said:


> I would quote people on this forum far before I would quote the APHA in terms of color knowledge. If it doesn't appear credible, I would track down a website that is far more updated on information and scientific fact than a registry.


Well, yes, but even my teachers in high school would not accept a forum or websites as a source. As far as equine color goes there really are not a lot *credible* sources out there that a professor/institute would deem acceptable. Unless you have access to online journals/periodicals - which unfortunately you have to pay for unless your school provides you with access. 
The registry, however, is still a *database* with mostly accurate information. 

I'm only emphasizing this part so her bibliography is admissible.


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## Chiilaa (Aug 12, 2010)

smguidotti said:


> The registry, however, is still a *database* with mostly accurate information.


Except that registries are NOTORIOUSLY inaccurate, so should NEVER be used as references. They are simply decades behind current research, and show no signs of changing that any time soon. There are credibility checks you can do on any website, and most universities will allow pretty much any website as a reference as long as you support it with a cred check. The only exception to this tends to be Wikipedia, which is open source and so therefore easy to manipulate.


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## Chiilaa (Aug 12, 2010)

smrobs said:


>


Tobiano, and frame at least. See the way the white is moving along the neck and body horizontally? That is classic of frame. Also remember that tobiano alone does not like neck white - it likes to cross the spine at the shoulders and no further forward. I want to say there is sabino there too, the face white looks fairly symmetrical, and the leg white has the jagged look I would associate with sabino.



smrobs said:


>


Sabino, yes, causing the roaning effect. Also frame - the body white is horizontal, neck white is present, and the face white is top heavy, spreading above the eyes. Another indicator is the dark and interrupted legs. Frame doesn't like leg white, so it is battling with the sabino to keep dark legs, hence the disconnection between white on upper leg and lower leg, and a nearly entirely dark leg.



smrobs said:


>


Splash for sure, also maybe frame. Just a bit of a spread above her eyes in the white, which is an indicator. Also that one leg that has fairly minimal white when she has highs on the other three legs.

As for eyes being blue, at this stage they are linked to frame and splash. However, that is just theory, and so far no definite link has been found.


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## Poseidon (Oct 1, 2010)

smguidotti said:


> Well, yes, but even my teachers in high school would not accept a forum or websites as a source. As far as equine color goes there really are not a lot *credible* sources out there that a professor/institute would deem acceptable. Unless you have access to online journals/periodicals - which unfortunately you have to pay for unless your school provides you with access.
> The registry, however, is still a *database* with mostly accurate information.
> 
> I'm only emphasizing this part so her bibliography is admissible.


I can't speak for the OP, but frankly, my equine profs have yet to be strict enough to make sure I provide a credible source such as some kind of journal when describing colors. In fact, most of the color sections we've had involved actual horses in a row and we had to name them. The fact that I could name off all of them without hesitation and with confidence was good enough for them.

However, that has been my experience because my profs are rather laid back.


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## MangoRoX87 (Oct 19, 2009)

My professor is pretty laid back too.

Okay, so let's see if I got this. Frame is like white spots On the body surrounded by color, and likes to avoid leg markings and doesn't put white around the eyes, correct?

Splash looks like a horse dunked its face and legs into buckets of paint. Splash causes blue eyes.

Sabino gives symmetrical face white, and jagged outlines on markings and those high funky whites, along with patterns that can sometimes almost mimic a rabicano.

So, if my (solid) gelding has a symmetrical blaze, chin white, and all even socks, he has splash and Sabino, correct? 

http://www.horseforum.com/horse-pictures/my-new-guy-134001/page3/#post1650743

Or are his socks caused by Sabino too since the edges on them aren't completely straight like?
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## MangoRoX87 (Oct 19, 2009)

And Tobiano does not create any Face white, right? I can tell the difference quite clearly in tobianos and (the dreaded word to y'all) overos, it's just getting the names and genes down right!
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## MangoRoX87 (Oct 19, 2009)

Bumppppp?
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## NdAppy (Apr 8, 2009)

No tobiano does not cause face white.  If there is face white on a tobiano you can be sure there is at least one other white pattern gene present.


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## Chiilaa (Aug 12, 2010)

I would say your guy just has splash. While his blaze looks symmetrical, it is falling off to one side from what I can see. That is a very typical splash trait.


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