Talk:Sabino horse

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Sabino is common in Hackney Horses & Hackney Ponies

Here is a Hackney Horse filly and her dam. The filly, has high white on all 4 legs, the full blaze, white lip, white between her jaw bones, small white markings on her belly and two white markings on her right hip. Both parents have a partially white lower lip and low stockings, but no other body markings, except for ermine marks on their coronet bands. Both parents have produced other get with sabino expression.--Panachehh 20:52, 23 April 2007 (UTC)[reply]

Here is a photo of Panache Sorceress at 1 month of age:

Good contributions, but I removed some commercial comments on this page. Please be careful not to "advertise" on Wikipedia, but your images are nice. Don't use galleries, either, I fixed the wiki markup to a more standard form. Montanabw 21:44, 23 April 2007 (UTC)[reply]

Gallery

Wrap-around, ragged-edged blaze.
Bold, irregular blaze that reaches the lower lip; pigmented spot on upper lip
Tapering white leg markings extending up the anterior of the hindleg
Irregular, sometimes tapering, white markings

Countercanter (talk) 14:58, 11 January 2009 (UTC)[reply]

Definition of "sabino"

Let's revisit this. The term "sabino" can be defined as:

Sabino-1
Any number or combination of white spotting patterns in which white markings are distributed primarily on the extremities and the ventral aspect of the body.

If falling under the second definition, sabino is distinguished from dominant white patterns in that sabino patterns are not supposed to be homozygous embryonic lethal.
If falling under the second definition, sabino is distinguished from standard white markings by...?

We can all agree on this, right? I might like to explore the last point...at what point do we draw the line? I know where many registries draw theirs, but that doesn't keep horse owners from calling horses "sabino." Countercanter (talk) 17:01, 24 May 2009 (UTC)[reply]

Kind of, sort of (grin). I think the safest bet is to SB-1 plus the organizational or registry definitions to show the other variations. Anything more isWP:NOR| "original research"]] and the wikigods will smite us! (LOL!) For example, we can do the "official" SB-1 definition from scientific sources, as it's been identified and such. But we can go on to show the range by using the variations used by the various breed registries and clubs that describe patterns whether they are or are not identifiable as SB-1. I think there are actually some links in the article to some of these places. For example, we can say the APHA definition of a sabino is abc (and they have a clear definition on their web site), the AHA doesn't officially recognize Sabino, but the Arabian Sabino Breeders Assn defines it as efg, the TWH people (whoever has a definition) define it as hijk, and the Clydesdale association defines it (if they do) as lmnop...

My thinking is to do a really good explanation of what SB-1 but also what it is NOT, then explain the other forms and the definitions used for non-SB-1 Sabinos. (particularly Arabians and Clydesdales, who do not appear to carry SB-1, but do have patterns that get called "Sabino.") You might want to see what I (and some others) did on the color section of Arabian horse as an example of an explanation of a non-SB-1 pattern.

For non-SB-1 sabinos, the usual definition is belly and flank spotting, high white, white past the nostril, eye or upper lip, body roaning or lacy markings in the same areas (which is sometimes confused with rabicano) etc. Clydesdales probably are the best example of a breed with a LOT of non-SB-1 sabinos. Some groups say if there is a chin spot, it's a sabino. To distinguish from standard white markings is basically the imaginary boundaries I just noted... genetically this may be inexplicable, but that doesn't keep people from trying. Montanabw^(talk) 05:42, 26 May 2009 (UTC)[reply]

Well, let's try to use the best sources first. Samantha Brooks, whose dissertation was Sabino-1, actually gets a great big star for Gets Along Well with Public. In this [1] APHA journal publication, she says some things that are so very, very useful:

"You can't say 'the sabino gene,'" Brooks explained. "It doesn't work that way. There are many genes that cause patterns that are commonly described as sabino, at least five [patterns] that I have seen. All of these have fundamentally different genetic causes, potentially different genes, so you really have to specify. It's correct to say 'the Sabino 1 gene' (SB1) or 'the sabino genes.'"

“I’ve had many an owner tell me that their horse must be sabino because it has this one leg with a sock that is pointy at the top, and that this is a sabino characteristic. Well, yes and no. Many sabinos do have pointy socks, but there are many different biological explanations for pointy socks, only one of which is Sabino 1. The draft-type sabino, for example,
is present in heavy horses, Shires, Clydesdales, etc. This population, until the recent popularity of draftcrosses and spotted drafts, was not intermingled much with the light horses. And, though it seems to be dominantly inherited, it does not produce a white phenotype.”

This is stuff that you, of course, know. The point that interests me is what she says about pointy socks and chin spots. Once one starts getting to high socks, they are almost invariably pointy. If they aren't pointy, they may indicate splash or tobiano. Incomplete thoughts, but I'll flesh it out eventually... Countercanter (talk) 13:04, 26 May 2009 (UTC)[reply]

Go for the rewrite on SB-1. My axe to grind in this is just that Arabians don't come in frame, splash, tobiano or any other form of Pinto other than whatever version of "sabino" they actually have, which apparently isn't SB-1. Ditto Clydesdales.

New discussion

Copied over from my talkpage: Sabino and splashed white. Hi, what's this I hear about calling splashed white patterns sabino? That's news to me. Is it by mistake because at the minimal end they look pretty similar, or are people knowingly referring to horses with splashed white patterning as sabino? Iamnotabunny (talk) 18:57, 18 October 2021 (UTC)

Good point, Iamnotabunny. As you see in the over-a-decade ago discussions above, there has been confusion in the past. And the article was a worse mess than I realized because it’s sat so long. Basically, I think the direction I was trying to go was to describe what the term “sabino” means, as it is no longer really a genetics term, it’s just a word that’s in flux to describe certain spotting patterns. Basically, because SB-1 is now understood as a W family allele, all the old stuff that was here about SB-1 versus “unknown genetic mechanism” is no longer relevant. But because the APHA still uses it, we probably need to continue to define it as well…and note its history. With splash genes still pretty newly identified (the article hasn’t been updated in ages), and some of the examples called “sabino” in the past are probably actually splash (The wide blazes with white on the chin especially), it’s actually a &*#&$ to visually tell what’s a W-family spotting and what’s SW. Anyway where you are sure welcome to go with this is “see what sources say and have at it.” Montanabw^(talk) 14:13, 19 October 2021 (UTC)[reply]

Hi Montanabw, thanks for putting this into context. A lot has changed since the last terminology discussion, the most important being, in 2015 researchers found one of the genes for "ordinary" white markings, it's viable in homozygous form, and it was named in the W-series (W20). This has sparked a lot of discussion around terminology, because it's unintuitive to call this W20 horse "dominant white" when he looks like a fairly ordinary chestnut. So now we don't just have the two definitions of "sabino" from before to choose from, we've also got questions like:

Is it okay to call a horse "sabino" if it looks like a horse with SB-1 but instead has an allele with "W" in the name?

Yes, sometimes. I’d say “sabino” patterning and SB-1 are not identical… some horses have a Sabino pattern because of heterozygous SB-1, but others have a Sabino pattern due to some other genetic mechanism, particularly W5. Similarly, some horses are pure white because of homozygous SB-1 – but others are pure white because of a different W allele. It’s like a venn diagram, kind of. If a horse’s genetics are known, one could say “this horse carries the Wfoo allele, and exhibits Sabino patterning/spotting/markings/whatever.”Montanabw^(talk) 16:34, 25 October 2021 (UTC)[reply]

What about a horse with sabino characteristics (roaned edges, pointy stockings, etc) whose genetics are unknown?

that would be precisely what the word “Sabino“ could be used for. In an article like this one, it would be appropriate to say, “the term Sabino was used prior to the availability of modern genetic color testing to describe horse spotting characterized by irregular spotting, roaned edges, pointy stockings…or “ this horse has Sabino patterning, though genetic testing would be required to determine the underlying alleles involved..“ Montanabw^(talk) 16:07, 25 October 2021 (UTC)[reply]

Can any horse with the broader sabino characteristics (white on legs, face, and maybe belly) be called sabino, even though splashed white can also cause such markings?

Yes, Thought I’d add the comment, “horse exhibits white spotting characteristics that have traditionally been described as sabino, though splashed white genetics may also create similar markings. Montanabw^(talk) 16:05, 25 October 2021 (UTC)[reply]

Makes sense. If a horse gets tested as having one of the splashed white alleles, it wouldn't be sabino though, right? Assuming no sabino-specific characteristics like lacy edges. Iamnotabunny (talk) 00:51, 6 November 2021 (UTC)[reply]

What should "W" stand for? Dominant white? White spotting? White?

W is identified as a allelic series that for scientific purposes would most properly be called dominant white, because W is a dominant gene, and it produces some degree of white when present. You can’t call the series “white spotting” because sometimes in fact it does create pure white horses. Also, markings aren’t spots. (There’s some researcher out there who’s getting bullied by idiots, IMHO.) I noticed that Sponenberg uses the phrase “white pattern(s)(ing)” a lot. I’ve actually emailed him once or twice over the years when I’ve had particularly thorny genetic questions, and I noticed his tendency is to choose the least amount of drama possible. I think one way a person could describe all the stuff is to say “the dominant white alleleic series, labeled W or in one case, SB-1, creates distinctive white patterns ranging from bold white markings to totally white hair coats.” And then note the stuff about terminology predating modern genetic testing. Montanabw^(talk) 16:05, 25 October 2021 (UTC)[reply]

Across species "white spotting" is commonly used as a general term for areas where melanocytes are not present, whether they be small white markings, fully white animals, or spotted patterns (though if only taking about fully white animals, more common is to just use "white"). I got curious and looked into terminology in mice, since horses are following their convention, and apparently in mice "W" alleles are called "dominant spotting", "dominant white spotting" (sometimes spelled as "dominant-white spotting" or as "dominant white-spotting"), or "belly spot". Not super relevant to horses but I thought it was interesting.

Anyway, "dominant white" does seem to be the most standard name for the W allelic series, but I'd prefer if we avoid using it in the more controversial ways. Iamnotabunny (talk) 00:51, 6 November 2021 (UTC)[reply]

Is it okay to call W-20 "dominant white" even though it's viable in homozygous form, and does not dominantly make a horse white?

yes, because it’s one of several dominant white allows that appear to be viable went homozygous. If you look at the dominant white article, somewhere in there is buried the explanation of which W alleles are embryonic lethal’s and which ones aren’t. Montanabw^(talk) 16:05, 25 October 2021 (UTC)[reply]

I know, I put it there :p Mentioned it since the previous discussion was using lethality as a possible distinguishing factor. Iamnotabunny (talk) 00:51, 6 November 2021 (UTC)[reply]

Is sabino a type of dominant white? Is dominant white a type of sabino?

SB-1 is a dominant white allele. It probably should have been labeled W, but at the time, describing it as sabino-white seemed like a good idea. (It wasn’t a good idea, but horse color breeding drama, whaddaya gonna do?) Sabino is a color pattern, like “pinto,” created before modern genetic testing was available. It is now known to be produced by a number of different alleles, just as white is produced by a number of different alleles. Montanabw^(talk) 16:05, 25 October 2021 (UTC)[reply]

(feel free to add in your own questions as well)

It's going to take some time to go through all the sources with these questions in mind, and I'll give updates as I go along. Iamnotabunny (talk) 13:47, 20 October 2021 (UTC)[reply]

@Montanabw: So far I've looked at Sponenberg & Bellone's book, Equine Color Genetics 4th edition. There is no glossary, unfortunately, but their use of sabino does not include splashed white, does include the phenotype created by some W-series alleles, and does include the Arabians and Clydesdales whose sabino has an unknown cause. Page 198 says that splashed white can be confused with sabino, but that there are some subtle differences. In the section on "Sabino and White", I see "sabino" being used as a phenotype, including for horses with a W-series allele, and sabino-1 used for the SB-1 allele specifically. It also mentions "Arabian and Clydesdale horses that are phenotypically sabino" (p 194), so it's not limited to horses with known KIT-locus genetics. One thing I don't see "sabino" being used for, is as the name of any particular allele. SB-1 is called sabino-1, and the W-series alleles are called either white or dominant white. I'll keep looking but I think this is going to be our best terminology source. I expect the published papers will be more concerned with communicating facts clearly than with defining words. Iamnotabunny (talk) 18:31, 21 October 2021 (UTC)[reply]

i’m guessing, but I bet the fourth edition came out prior to the discovery of the SW genetic series. It sounds like W 20 may have popped up in Clydesdales? We also now have three other W alleles found in Arabians, most I think create predominately white horses, though the one linked to Khartoon Khlassic finally answers the question of what the heck Khemosabi (horse) was throwing, and we Arab aficionados called that “sabino” for decades. Montanabw^(talk) 16:12, 25 October 2021 (UTC)[reply]

Sorry, meant to reply to this way earlier, but it's from 2017, and includes info on SW-1, SW-2, and SW-3. I agree with their assessment that splashed white has some tells that distinguish it from KIT-related spotting even in the more minimal forms where both make white markings; they mention sabino's lightning marks on the legs but I've also noticed some differences around the eyes and nose between horses tested as SW and horses tested as Sb/W.

W20 is really old, from before the formation of breeds as we know them. That's why it's so widespread, across so many different breeds. It may sometimes occur in Clydesdales, but I don't know how common it is there. I think I'd have heard something about it if it was the Clydesdale sabino. I expect many variants similar to W20 will be found someday, and perhaps Clydesdales will turn out to have a mixture of many small effect variants rather than a single one. We'll see.

I don't think anyone knows what Khemosabi was throwing. Khartoon Khlassic is the founder of W15, so it can't be that. Iamnotabunny (talk) 00:51, 6 November 2021 (UTC)[reply]

Sorry not to pop by sooner…you can always ping me at my talkpage so I get an email…the bottom line is that sabino is becoming an outmoded term, but places like APHA still use it. I’ll answer the other stuff inline…You’re right that only SB-1 is still called “sabino” anything. Arrgh. I think we just need to discuss the drama and source who argues what. Montanabw^(talk) 09:06, 25 October 2021 (UTC)[reply]

(Oops, forgot to ping @Iamnotabunny:. Montanabw^(talk) 16:24, 25 October 2021 (UTC)[reply]

About W20

If you look at the dominant white article, buried in there rather deeply is a description of how all white markings are related to the migration of melanocytes. So I suppose, one of these years, someone might discover yet another gene that “makes white markings happen.“ KIT is definitely earning a lot of tenure for various researchers. If you can link the research papers that discuss W 20, that would be awesome. The picture you have above in the link of the W20 horse, the thing that jumped out at me immediately is that he had white body spots. That was the giveaway, and I have seen similar faint round white spots on Arabian horses that we now probably would call “sabino” —and possibly produced by W15 or W20. Montanabw^(talk) 17:10, 25 October 2021 (UTC)[reply]

Here's a link. The two W20 horses pictured in the paper don't seem to have body spots, though who knows, there could be on the other side. The paper mainly talks about its effect when combined with W5, since that's how it was found. The original paper doesn't mention white markings (probably because that sort of thing is hard to prove to the same standard) but various other sources do. I've also heard of a few W20 horses with no white markings at all. I think it's pretty cool how all these "white" things, markings, pinto, what have you, have got the same sort of underlying thing going on. I just happened across this article which I think explains it pretty well. The research they talk about is probably this. Iamnotabunny (talk) 01:33, 6 November 2021 (UTC)[reply]

@Iamnotabunny:. Thanks for your edits. I remember when I was working with Countercanter on these articles way back, she commented then that KIT seemed to have something to do with even ordinary white markings. It’s going to be interesting to see how the science develops. I think the main thing is that we don’t want to jump the gun, particularly with naming conventions …a lot of the science is still in flux. I’m going to mull over the articles you linked and see if I have further thoughts. Montanabw^(talk) 04:17, 9 November 2021 (UTC)[reply]