Pronounced white markings
Very interesting white markings on this 100% Crabbet stallion (with multiple lines to Skowronek and Dargee) and a tail female line to the Kuhaylat al-Krush desert-bred mare Dafina.
The VIIIth century CE Arabic horse books (kutub al-khayl) describe such markings at length. There must have been more Arab horses with such markings in the past, before these were bred out, and it’s interesting to see them pop out again in a pedigree like this one.
Some eleven years ago, the late Joe Achcar posted the photo below, showing a similarily marked stallion of Syrian and Egyptian bloodlines.
I have often thought of this white markings question. What type of white is a sign of non Arabian blood? I’m not sure there is a firm answer.
I remember speaking about this topic with Basil and he showed me many photos of asil horses in Syria with white above the knee. They were nothing quite like the Crabbet stallion above though.
For the Crabbet stallion in the first photo, a control group could be markings of horses with the same or similar Crabbet blood but without the non Arabian blood of Skowronek/Dargee. I know through my experience that the huge splashes of white on the belly and legs far above the knee to not manifest themselves in this group. In fact, despite having multiple crosses to chestnut ancestors with 4 white feet, it seems that few of the 100% Crabbet non Skoronek/Dargee horses have 4 white.
Of the 100% Crabbet horses of asil blood, the one with the most white I have seen is the gelding “Crabbet” who’s pedigree is below.
https://www.allbreedpedigree.com/crabbet
There’s a South African-bred Straight Egyptian mare, Imperial Asil Akilah, who has a large white mark on her left hip. Very unique!
Love the high whites that come from Mesaoud and Rodania breeding. Rikitea (Rissalix x Nurschida) is another striking example, with her four stockings and big white blaze. Of the modern Crabbets, Fenwick Orion has similar markings to Marbon Masterpiece, as does Eliseo SPA. I suppose it is no surprise that the Crabbets come with chrome; I do recall reading somewhere that Mesaoud’s sire was parti-coloured, but can’t lay my hands on that quote.
Lady Wentworth, for what it is worth, says in The World’s Best Horse that “Abbas Pasha had a parti-colored Wadneh Hursanieh mare by a Shueman Sbah sire called Tabbukh belonging to Mohammed Ibn Khubeysan. She originated with Hamoud Ibn Saadun Sheikh of the Muntaghaj, and was a great granddam of Mahruss I. It is from her that the white patches seen in some of our horses such as Nezma, Shareer, Astrella, and Shafina are probably inherited.”
The SE mare Moneera (Alaa El Din x Mouna) had a lot of white ticking in her coat, a white tail head, and what looks like a large white patch over her loins in the one photo I’ve seen of her. (She’s also got several lines to Mesaoud.)
I am not sure that parti-colored was the right translation for the color of that Wadneh mare of Abbas Pasha.
I don’t remember ever reading that Mesaoud’s sire Aziz was parti-colored. If you can find the reference, let us know, but I don’t think there is one.
Lady Anne Blunt wrote in her journal for Nov. 24, 1880, the first time she saw Aziz, that he was “a handsome Dahman Shahwan chestnut with 4 white stockings.”
I have done some digging through the internet, and think that the parti-coloured sire of Mesaoud is a garbled version (garbling done by yours truly) of an assertion I’ve seen several times this afternoon, that Abbas Pasha had a parti-coloured stallion Al Mahyubi, brother of the grey stallion Jadib, from whom Mesaoud is supposed to descend. The source for this seems to be an article by John L. Baker called “Mesaoud, the spotted wonder”, but which apparently does not exist online. So not a reliable source that can be verified!
Digging also turned up a claim that Faras Saouda was piebald. That comes from Sandra L. Olsen’s 2017 article “Insight on the Ancient Arabian Horse from North Arabian Petroglyphs”, Arabian Humanities 8.
Lyman, please read again what Edouard wrote: “There must have been more Arab horses with such markings in the past, before these were bred out[.]” I can’t post pictures here, but the Blunt/APS pedigrees produced more white markings variation than you allow for.
I have been convinced for decades that the very strength of the prejudice (which as Edouard has agreed is based on cavalry markings requirements) is proof of their original status and long-term persistence in the breed.
Micheal-
I agree that perhaps the largest bias and/or prejudice in Arabian horses is color and/or markings in general. Color/markings are the first thing one notices in a horse and for most people, its hard to overcome.
The most popular and effective way to breed out white markings on chestnut horses is to not breed chestnuts at all. Observers can see this in the SE community where there appears to be a strong bias towards grey horses in particular. Others of course like black because black. Reading “The Egyptian Alternative,” breeders seem to be horrified at the thought of a chestnut with 4 white. What would people do with such a horse!?!?
Another often used term is “high white.” This of course means different things to different people.
The horses Kate quotes above from Wentworth, Nezma, Shareer and Astrella in their photos on allbreed have levels of white I have seen on ancestors of my own horses. Their markings do not seem “high white” to me.
It is my view that within the world of 100% Crabbet horses there are two groups: Crabbet purebred Arabians and Crabbet part bred Arabians. The second group of course being infected with the blood of the part bred stallion Skowronek. I think its important to distinguish between the two. An example of a Crabbet part bred horse is the first photo above, Marbon Masterpiece. I have never seen anything remotely close to this level of white in Crabbet purebred Arabian horses.
I believe the white markings exhibited on Marbon Masterpiece come from the non Arabian blood flowing through his veins, not remnants of white markings that have been bred out over time due to the personal preference of breeders long ago.
Regardless, I’d love to see more white markings on Crabbet purebred Arabians. You can upload them to google docs and share a link and paste it below.
Faras Saouda was piebald? How does Sandra L. Olsen know that?
Lady Anne Blunt’s notes refer to Faras Saouda as a “black” mare, with Lady Anne putting “black” in quotation marks. No reference to markings.
There are a couple of entries in Prince Mohamed Ali’s translation of an Abbas Pasha manuscript that might, or might not, refer to Faras Saouda.
One reference is to the “parti-coloured mare, Wadnah al-Khursani.” Maybe this is Faras Saouda, or maybe not. Even if it is Faras Saouda, according to the Forbis/Sherif translation of the Abbas Pasha Manuscript, the Arabic word in Prince Mohamed Ali’s book translated as parti-coloured is “rabsha,” which actually means a grey with a profusion of black flea marks. Not pinto. Not chestnut with high white. Not piebald.
Maybe Sandra L. Olsen was using Lady Wentworth as a source. Lady Wentworth seems to have been reading right out of Prince Mohamed Ali’s book when she discussed the parti-colored Wadnah mare in The World’s Best Horse. The complete entry from Prince Mohamed Ali reads: “The parti-coloured mare, Wadnah al-Khursani; father Shuwayman al-Sabbah whose name was al-Tabbukh, the stallion of Mohammad ibn-Khubaysan. This mare originally belonged to Hammud al-Sa’dun, the Sheikh of Muntaghaj.”
Lady Wentworth said that Nezma, Shareer, Sharfina, and Astrella had “white patches,” which I took to mean a reference to white belly spots, not high white stockings. Although they also had white stockings. For what it’s worth, both Astrella and *Rose of Sharon had more white on their faces than what Marbon Masterpiece has.
Olsen cited Margot Weise’s A reference guide: Arabian coat coloration as her source, so I have looked that up, and here are the relevant passages from Weise that Olsen was relying on:
“Some of the most flamboyant patterns and shades were not thought impure in the desert but were actually sought after. One of the Abbas Pasha’s most celebrated mares was Faris Saouda, a parti-color (wildly spotted) horse. This ancient gene is not a sign of impurity but exactly the opposite. The true parti-color is not a common spotting pattern as seen today, but instead is the failure of pigmentation cells to spread throughout the body of the horse, a unique mutation occurring mostly in hotbloods. The Abbas Pasha set great store by this color and collected 11 mares with these attributes.”
“The true parti-color is hardly ever seen today and is strictly hotblood in origin. Desert Name – Ablak This color is not related to the tobiano or the overo gene groups. Appaloosa type spots in the Arabian also seem to be a throwback to the parti-color. These horses are not eligible for the Appaloosa registry, even though some could be confused with the true Appaloosa.”
Olsen reduces this to “Abbas Pasha had 11 mares in his Egyptian farm that were parti-color (piebald), including one of his favorites, Faras Saouda.” She adds piebald as an explanation, but this is definitely not what Weise was saying.
Re Lady Wentworth’s “white patches”, I also thought of belly spots.
Finally found a photo of Nezma showing her belly spot, which was on her near side. Notably, all the formal, posed photos that I have come across so far show her off side. The Daoud daughter Marhaba is another with a belly spot, though no high white; she does have a large snip, and half of her top lip is white. I’m on the lookout for quality versions of the pictures, and if I find them, will post them.
The Sharfina son Shafreyn had some very extravagant white markings; he was also an Oran grandson, giving him a line to Astrella as well, plus his sire’s dam Grey Royal was out of Sharima, so lots of Mesaoud in the back of his pedigree, not to mention at least six lines to Rodania that I can see in the first five generations. He was exported to Australia.
(As a side note, I am grumbling a lot about Lady Wentworth’s penchant for retouching photos of her own horses, and how difficult that is making this search.)
Weise’s whole discussion seems to be based on the appearance of the term “parti-colored” in Prince Mohamed Ali’s translation of Abbas Pasha manuscripts. English-speaking readers, including Lady Wentworth, have interpreted parti-colored to mean chestnut with profuse white markings, when it seems to be (according to Sherif and Forbis) simply a misleading translation of the Arabic word rabsha meaning a heavily flea-marked grey.
Keep in mind that Lady Wentworth came from a dog breeding background before she took over her parents’ Crabbet Stud, and in the show dog world, parti-colored does mean large splotches of one color combined with white.
Wait a minute, Astrella doesn’t have Faras Saouda in her pedigree (although Nezma, Shareer, and Sharfina do). I guess even Lady Wentworth makes mistakes.
How would Trabag fit into this, do you think? She was Crabbet and Ayerza.
That Faras Saouda was piebald makes no sense in light of her name which means Black Mare.
I’m actually not certain what Weise means by parti-coloured, as she outright says it is not related to the normal pinto patterns of tobiano and overo. The fact that she compares it to appaloosa spots makes me wonder if she’s referring to Birdcatcher spots, or perhaps a dominant white mutation of the sort that used to be called sabino. A heavily flea-bitten grey sounds much more expected as a colour for Arabians, though. At any rate, I am scratching my head; and it certainly doesn’t make any sense that Faras Saouda would be a piebald.
Trabag’s a weird one, as manchado has only been recorded in Argentina to date, as far as I know. She didn’t pass her pattern down to her foals, either, suggesting that it is recessive, but right now manchado is a mystery.
Mesaoud had 4 white stocking with none above the knee. I think it is unreasonable to attribute white on a horse at levels shown in the photos posted to him.
Regarding belly spots, the belly spots I have noticed on Crabbet horses without Skowronek are usually smaller than a man’s outstreached hand. Often times they are smaller than your palm. Compare this to the Pinto like spots on Crabbet part breds.
Within Crabbet purebred Arabians I have often thought Queen of Sheba to be more of a potential source for white than Mesaoud.
Both Mesaoud and Queen of Sheba are about as asil as you can get by the way.
If you are going to talk about white in Crabbets and point to asil horses as the source, then you really have to show photos and talk about horses that are purebred. Without any crosses to known part breds such as Skowronek.
I have been looking through old Polish magazines and books to try find photos of the Polish domestic lines with flashy white markings, and I have to say I am having a pretty hard time finding extreme white at all, let alone with the regularity of the Crabbet horses. If Polish breeding is the source of extreme white, I would honestly have expected to see it more often. There are a lot of greys, and a lot of minimally marked horses, though horses with big white blazes and stockings to the knee/hock do exist as well.
However, if you have pictures of the Polish domestic lines tracing to Milordka, Szweykowska, Ukrainka, etc, that do not include Mesaoud and the other imported Crabbets in their pedigrees, and that show flashy high white, including belly spots, please do share them. I would love to see them.
From a genetic point of view, the extreme high white with belly spots is a fairly typical expression of sabino-like markings across a variety of breeds. W20, for instance, is found in the Arabian breed, and is known to produce stockings, blazes and belly spots. It’s also a white booster. Anyway, the KIT gene is prone to novel mutations which produce a variety of white spotting patterns, so unusual white that is not tobiano or overo is not by itself an indication that a horse is not purebred Arabian.
Also, I have found a photo of a Syrian mare, a Hamdaniat Ibn Ghurab, who has high white above the knee and hock, belly spots, and a big blaze. So the possibility for flashy white markings does indeed exist in the Syrian Arabians.
I believe that 19th century European importers of Arabians from the desert selected against lots of white, and some against grey, because they were breeding with a cavalry market in mind. That would not have bothered Egyptian pashas, I assume.
I am kind of laughing because nobody has yet mentioned the epynonymous *Crabbet (Rijm x Narda / Rejeb) who is 100% Crabbet, double Mesaoud with nary a single cross to Queen of Sheba — AND the horse has not only the wide blaze that crosses under the jaw, the high white, and the irregular white: but he’s a markedly large belly spot.
http://farm1.static.flickr.com/13/89644046_1d18788122.jpg?v=0
Oops, eponymous*
Yes, Trabag was a brindle roan! Beautiful coloration.
I saw a Doyle filly in Colorado who had the same coat pattern. Can never remember her name but RJ will have it.
Have read that chimerism is usually the cause but not always.
Moira- Check out my reference to Crabbet on the first comment of this thread.
Regarding the reference to Queen of Sheba, I mixed up my chestnut desert bred Blunt imports. I should have said Rodania.
I think the single most important factor in trying to look for where the paint like markings on Marbon Masterpiece and other part bred Crabbet horses come from is to look for part bred greys in the pedigree.
Grey horses mask white markings. This is why modern Egyptian breeders like greys: they are horrified of the white markings that appear with chestnuts, however minor.
Polish half breeds like Skowronek simply have too many greys in their pedigree to pinpoint the exact source. It is enough to know that non Arabian blood exists in his pedigree. Full stop. Even the horses that could plausibly be Arabians are not documented very well. Some European who did not know what an Arabian horse was went down to what could be considered greater Syria and bought a grey horse named Saglawi. End of story.
So where does the white come from? I think its a question of degree. Let’s compare 100% Crabbet pureblood horses with the Crabbet half breeds in the photos above and elsewhere.
Let’s take the head:
Crabbet pureblood horses with significant white markings on the head include the horses below. In some cases it covers half their head.
Rose of Sharon
Astrella
Astraled
Crabbet
The legs:
Mesaoud- 4 white with none above the knee
Mahruss- 4 white with none above the knee
Astraled- 4 white with two legs just past the knee by several inches.
Crabbet- 4 white with one leg a few inches past the hock.
Belly spots:
These are harder to see, but normally the largest ones are about the size of a man’s outstretched hand.
Let’s compare these markings to Marbon Masterpiece in the photos above:
The head:
Nothing about head from the angle the photo is taken is abnormal to me. Even if half the head was white, its still not abnormal.
The legs:
White markings running up 4 legs that are an inch or two from the belly of the horse to me is a sign of impurity. If it was 1 leg, I’d say it was inconclusive. But all 4, and all the way up to the belly. Sorry, he’s a paint.
The belly:
Massive white markings the more than the size of a human head. Sorry. Paint.
Lets take the other two photos on this page:
http://daughterofthewind.org/other-mostly-crabbet-horses-with-pronounced-white-markings/
Fenwick Orion
The head:
The only thing suspicious about the white markings on his head is the small one under the jaw on the left side. As well is the line running out from the right hand side sort of near his mouth.
The legs:
4 white running up the whole leg and nearly connecting with the belly. Sorry. Paint.
The belly:
Massive white markings the size of a human torso. Sorry. Paint.
FV Aul Rabba
The head:
The front of the head looks OK to me. The right side of the head shows markings running along the jaw, and random spots on the jowl. These look suspicious to me. Likely evidence of non Arabian blood.
The legs:
Nothing conclusive there.
The belly:
The belly spot the size of several human heads and other random small white markings scattered here and there. Sorry. Paint.
“From a genetic point of view, the extreme high white with belly spots is a fairly typical expression of sabino-like markings across a variety of breeds. W20, for instance, is found in the Arabian breed, and is known to produce stockings, blazes and belly spots. It’s also a white booster. Anyway, the KIT gene is prone to novel mutations which produce a variety of white spotting patterns, so unusual white that is not tobiano or overo is not by itself an indication that a horse is not purebred Arabian.”
Sorry, I don’t buy it. For this to be true, there had to have been a mutation of a horse somewhere in England. Magically, in the US, UK, Australia and SA numerous horses with Skowronek in their pedigree can pass for paints.
The ones that don’t have Skowronek in their pedigree with significant white markings generally have white markings along the lines of their Crabbet ancestors or distant cousins such as Mesaoud, Rose of Sharon, Astrella, Astraled and Mahruss.
As mentioned above, I think its a question of degree.
People have commented on the first photo above, but not so much on the second photo which Joe Achcar shared many years ago and Edouard reposted.
Here’s my thoughts on that one:
1. What is the pedigree of this horse? Are there any ancestors that could be considered non Arabian? If yes, I’m inclined to think the markings come from the non Arabian ancestors. If not, and the pedigree is as clean as it gets, then I would ask the next question:
2. Do similar markings appear in other horses of similar bloodlines? If yes, perhaps you might reconsider your answer to question one. If no, and this is a one off occurrence, then I think some type of mutation is the likely cause.
3. If you still think this horse has no potential non Arabian ancestors and there are others that have similar markings, then I believe this horse is indeed a throwback to the horses Edouard is saying existed over 1000 years ago, and it is a sign of purity not of impurity.
This marking looks almost like the bloody shoulder markings you find on a greys but sort of inverse and on a chestnut.
Lyman, you must have *Astraled confused with some other horse. *Astraled was a dark bay with a small snip and a partial coronet.
RJ- You are right. I confused Astraled with Abu Zyed above.
Lyman – ah, I just assumed you were talking about the Crabbet breeding group. My bad.
With that said, “Sorry, I don’t buy it. For this to be true, there had to have been a mutation of a horse somewhere in England. Magically, in the US, UK, Australia and SA numerous horses with Skowronek in their pedigree can pass for paints.”
I mean, if you start actually looking at the horses in early Crabbet pedigrees that don’t carry Skowronek, instead of making others do the legwork for you, you’d see that there’s an astonishing amount of horses that have wide blazes, white that crosses under the jaw, irregular white patterning on the legs that frequently appears on 3, if not 4, legs, and markings that either ARE high white or were very obviously trying to extend into what we commonly think of as high white territory, ie above the knee. A very incomplete and very cursory list could include: Ribal, Rahal, Rifnas, Rasima, Daoud, Rose of Sharon, Rose of Hind, Rejeb, Rumeliya, Narda, Abu Zeyd, Antika, Feluka, Hamasa, Harb, Razzia, Rodan, Jeruan, Naaman, Nadir, Rijm, Crabbet, Rokhsa, Roshana, Rajih, Ramim, Rangha, Ibn Mahruss, Nasik, Nurreddin II. Heck, throw in horses crossed to Dwarka (a very minimally marked bay horse) and we have horses like Namilla, Aldebaran, and Algol.
I think you are VASTLY underrating the prevalence of white spotting in the early Crabbet gene pool. I’m in concurrence that this is likely a gene expression that already existed in Arabians, particularly given that we’ve seen in in cradle Arabians before, and that the expression has been downplayed as impure/undesirable by Westerners seeking to use the Arabian as a cavalry mount or breed improver. It is also worth noting that, the further out we get from the original Crabbet importations is when we see a tightening of the gene pool and a higher repeating of ancestors, making it more likely that the various white spotting genes across the board will meet and express with one another.
The other thing I will say is that Lady Wentworth had a penchant for photoshopping her horses, and I wouldn’t have put it past her to photoshop horses that had the belly spots. It’s also penultimately interesting/frustrating to me how many Crabbet horses have essentially disappeared from the record with no photographs, and with no way to prove or disprove what their white markings looked like. It calls to mind stories I’ve read of older breeders from back in the day who have had crop-ups of horses with intense white that they culled in one way or another, believing the white to be a flaw/defect/sign of impurity.
Interestingly enough, the Doyle breeding group has had at least one horse that had a large belly spot — JADY — with plenty of others with loud markings. My guess would be that, with such a small gene pool, your horses missed the white booster gene.
Thank you, Moira. As I said on the other thread, perhaps we have just stopped culling these and selecting against the extra white.
Can someone please explain the genetics behind these loud white markings, at least as it is currently understood?
Many thanks in advance!
Moira-
None of the horses you mention above even remotely come close to Marbon Masterpiece or Fenwick Orion in terms of white.
I don’t see how you get the drastic change from the whitest Crabbet horse pre Skowronek which I think is the gelding Crabbet to Marbon Masterpiece without……Skowronek and all the garbage that comes with him.
My point is NOT that white markings are a sign of impurity. White markings at the level of Marbon Masterpiece yes….presence of impurity.
White markings at the level of the gelding Crabbet no.
Sorry, Lyman, I just disagree with your premise there. I don’t believe it matches the genetic research into white markings, as Michael Bowling points out in a more recent thread.
GENETICS !!!
Here i come ^^
For once….i may suggest going to take a look at a simple Wiki page for the White pattern to be found among Arabians : https://en.wikipedia.org/wiki/Dominant_white
If you want to get a little deeper into this you will have to check embryo development and how genetically coded inhibitors ultimately prevent melanocytes migration and production causing white spot patterns.
If I could provide a good image think about the embryo development as a scheduled timer. Genes are encoded so that on a scheduled timer pigmentation cells cannot migrate resulting in white patterns appearing (KIT related) or simply are not produced (MITF related). The combination of both create the various patterns you can observe on phenotype.
There is a lot of research going around the KIT and MITF genes which are causing piebaldism (inhibator related) because it is also related to cancer cells (activator related). So research on anything KIT related is very important.
Anyway what you should know right now is that :
– If i am correct we are still (for horses) considering about 82 000 protein locations on the third chromosome for KIT and about 210 000 for MITF. Which would provide about 34 milliards of variations for a chromosome pair if i am correct.
You can easily imagine the possibilities…of course not all of them are possible. Every protein is not active so not all of them are causing variations. And every living being inherits it from its parents (so far XD) so they tend to follow standard settings until a new variation occurs through mutation.
– So far horses have shown great level of genetic mutation abilities. And last but not least the horse to date is the richest livestock specie in terms of alleles heterogeneity. Both being linked would not be surprising.
– As for the Arabian horse, to the very best of my knowledge, the various patterns are not all genetically understood.
The Roan pattern is not yet genetically mastered for the Arabian horse.
The piebald pattern is only known for Dominant White in Arabians : W3 (descendants of R Khasper https://www.allbreedpedigree.com/r+khasper -mutation ancestor which is anyway not Asil) and W19 (descendants of Fantasia Vu https://www.allbreedpedigree.com/fantasia+vu2 – possible mutation ancestor and not Asil either anyway) PLUS W20. W20 itself is not yet fully understood, as it does not itself cause large white spotting patterns but rather seems to extend the effect of other variations on KIT. It makes no doubt that many Arabians Asil or not are W20 carriers but it does not make them piebald just on its own.
The grey patterns are not yet fully understood and we have many very interesting ones in and outside Asil lines : including inhibited greys, fleabittens, dapples etc.
The various shades are not yet fully understood either and we have many very interesting ones also in and outside Asil lines : flaxens, possible sooty related genes causing liver chestnut or black/bays
All in all I can tell you that we know that we don’t know until we can trace back every mutation ancestor of every allele variation….and that we don’t know yet all of these variations. And while we are searching for those, new ones may occur.
Thank you for reading ^^ this was the genetic blabla of the day
Jeanne-
I’ve thought about it and I will rephrase my last statement:
My point is NOT that white markings are a sign of impurity. White markings at the level of Marbon Masterpiece (within 100% Crabbet horses) yes….presence of genes tracing to the part bred stallion Skowronek and all the garbage that comes along with him.
White markings at the level of the gelding Crabbet no.
Sorry to revive this, but I have been revisiting white patterning in Crabbets, and I do have something to add – another problem I have with the idea that Crabbet Arabians with level of boosted white as evidenced in the original horse of this post, Marbon Masterpiece, is that EVEN IF it was introduced via Skowronek, that doesn’t ipso facto mean that whatever is causing the boosted white is a ringer for non-asil bloodlines.
We don’t know how old that mutation is. We don’t know how Skowronek would have gotten it – whether via his questionable ancestors, or via his desertbred ancestors. – we don’t know if it came from the desert itself, or if it was a spontaneous mutation from descendants of these desertbred ancestors (asil or otherwise.) We don’t know if it is a KIT mutation, or a MITF mutation, or a mutation from somewhere else. We don’t know if it is linked on the MCR1 gene. We don’t know if it is linked to the e mutation or the wild-type extension. We don’t know if it came from an ancestor that also had a white masking/suppression gene.
It’s really easy to point fingers and say “this means a horse is impure” but genetics just aren’t that cut and dry, and we know too little to be able to make definitive statements based on the white markings themselves.
It’s like how blue eyes used to be considered a sign of impurity, but all they are is a “blip,” a little oopsie, that occurs when the melanocytes are migrating from the neural crest during development. They’re basically a “white spot” on the eyes, and are caused by a number of white patterning mutations.