Splash overo


Okay, maybe not love – but certainly stop worrying about it.

Like a lot of people who find horse color fascinating, I once spent no small amount of time online, spreading the Gospel of Proper Color Terminology. Surely if I just presented the facts in a convincing manner, I could save the world from people who were convinced they had palomino Arabians!

Fortunately for my own sanity, my career as a parent – begun just a few years after large numbers of horse people discovered the internet – got in the way of my missionary zeal. Toddlers do not recognize the need for uninterrupted bathroom breaks, never mind enough time to compose an extended explanation about why you really should not call your double-diluted cream an albino. Children also raised my threshold for the type of thing that required immediate action. I could live with someone on the internet being wrong; it was not like they had just painted on my bathroom walls with chocolate pudding.

Looking back, though, I see that my enforced absence from online discussions had unexpected benefits. For a researcher there is a significant downside to spending a lot of energy “correcting” wrong information. If you spend too much time telling people that some common misperception is wrong, you run the risk of having that response become automatic.  It makes it a lot harder to reassess your position, because it is a rare person that can argue a position for a long time without getting their ego involved in being proven right. From there, it is easy to overstate your case. “Your flaxen chestnut Arabian is not a palomino” becomes “there have never been palomino Arabians”, which then becomes “Arabians do not carry any dilution genes.”  The first is – or at least to date has been – true. The next statement is actually open for debate, and the last one is incorrect. (See also, here. Similarly diluted Morgans can be found here.)


And intriguing painting of the early Twentieth Century Turkish Arabian, Übeyyan.
How accurate was this portrait? And what color was he?

The other downside to spending a lot of time correcting errors is that if you automatically dismiss something, it is really easy to overlook important information. Even when people are wrong, they may still hold a clue, a piece of the puzzle you are trying to assemble.

I sometimes get asked why I spend so much time with older documents when so much has changed in our understanding of coat color genetics. Why, for instance, spend time translating Valto Klemola’s 1931 paper on “Recessive Pied” when there are papers written just this year and last on what we now call Splashed White? Surely the new information replaces Klemola’s theory about recessive spotting in horses.


I am sure my husband also wonders why I need books about horse color published in 1912. After twenty years of losing more and more shelf space to them, he has given up asking.

But the fact is that Klemola – and many of the other earlier authors – were not entirely wrong. They were almost always working from a partial picture, but often the piece that they were seeing was not incorrect. It was simply incomplete.  Read with an understanding of the larger picture, what these older researchers have to say can still provide valuable information. The same is true for owners and breeders who may not have the same grounding in the latest scientific theories. They still have the potential to be valuable observers. It is worth being open to what they have to say, without being excessively concerned about the “correctness” of how it is said.

At the moment terminology – particularly the terms we use when talking about white patterns – are in a state of transition. We are struggling with words that do not completely fit our present understanding. I hope to tackle that in more detail in a future post. It is worth remembering, however, that the real reason for adopting a consistent set of terms is so that we may all communicate more clearly with one another. It may take a little more effort, and perhaps a few more words (and patience) than it once did, but that is ultimately the goal.


I think I need to work on final book edits every spring, because it seems to guarantee that a paper will come out within that time period. Animal Genetics has a short communication out with three new KIT mutations and one new PAX3 in horses. There are also two papers out on KIT patterns in dogs, which is new. Before this, the piebald patterns in dogs had been mapped to MITF, which in horses is the other site for splash white. The picture above is the German Shepherd that carried the de novo mutation. (I must give a special thank you to her owner for allowing me to include it here.) I had intended to put together a longer post on this pattern, known as panda, because it touches on the subject of blue eyes in KIT mutations. She obviously has blue eyes, and her owner confirmed for me that some of her descendants have had a blue eye or blue segments in their eyes. This follows the pattern that I have seen in the historical records of some suspected Dominant White horses (also presumed to be KIT mutations). Blue eyes do seem more common in the originators, and then appear to occur sporadically – often in a less pronounced degree – in the descendants. Interestingly enough, the MITF mutations are not associated with blue eyes. In fact, this family of Shepherds was the first instance I noted where blue eyes in dogs were linked with a form of white spotting so I was particularly happy to see the mutation formally identified.

What is interesting about the new equine discoveries is that they really do not fit neatly into existing naming categories. The KIT mutations have been assigned numbers in the “W” series, but at least one appears to be subtle white-booster rather than a true dominant white. I had been urged by a couple of researchers, as I got close to my publication date, to avoid the use of the term “sabino” and just use “white spotting”, and I see now why. I suspect this will become more complicated as time goes on and more mutations are identified. One thing does seem clear, and that is that several of these sites mutate often – apparently in ways both large and small!

Just as I did with the book last year, I’ll be updating the text to reflect this new information for the new full-color supplemental book. I had feared there might not be much new information, but this coupled with some of the things I have been researching in the last few months should make for a lot more content as well as more abundant (and colorful) images!

I wanted to get pictures of one of the new horses at our barn, Dutch, to use for a post on sooty patterns. Dutch was interesting because he has the very dark forehand that some sooty buckskins get. I also thought artists that read the blog might find the abrupt transition between his body color and the black front legs interesting.

I had only seen Dutch at a distance, but I had gotten the impression he had somewhat paler-than-usual eyes. Light brown eyes are not uncommon in buckskins or palominos, so that would not have been unexpected. When I got close enough to take this picture, the reflection from his eyes looked off. (All the images in this post are larger than they appear, and since the details are small, I highly recommend clicking them to see the larger version.) Instead of looking pale brown, his eyes looked like the reflective gleam was in the wrong place. That is more noticeable in this face shot.

Over the years I have learned that odd reflections in the eyes sometimes mean the horse has a blue segment, and sure enough, that was the case with Dutch. Although he has no white markings at all, both of his eyes have flecks of blue. The largest one is located close to the bottom of his right eye, and is what is giving the odd reflection.

As can be seen in that photo, he has a number of blue flecks in that eye. His iris also has irregular patches of golden brown and darker brown, giving the whole eye a marbled look. Although it was more visible in brighter light, even without the light directly hitting the eye the blue areas could be seen.

His left eye had smaller flecks of blue that were much harder to capture on film. (This is the image that would most benefit from clicking, since the flecks are so small.)

He would be an interesting horse to test for splash white. So far a couple of individuals without white markings of any kind have tested heterozygous classic splash white (SW1). Perhaps Dutch carries SW1, too. It is also possible that there is some other yet-unknown cause for the blue sections in his eyes.

Anyone who has followed the results from the new splashed white tests knows there have been some really surprising results, both in how many horses test negative, and in some of the horses that have tested positive. For those of us that had been studying “classic splash” (splashed white-1) for a while, some of these were perhaps less surprising because we knew that there were blue-eyed horses that looked somewhat like splash, but that did not produce the classic pattern (what we believed to be homozygous). But even there, there have been unexpected surprises. Probably the most dramatic was the Bald Eagle family of Australian Paints. For those that have the Gower color book, this is the splashed white family that was profiled there. I would have guessed (wrongly!) that those were homozygous classic splashes (SW1/SW1) with some type of sabino patterning.

I may have another wrong guess. I have believed that classic splash (SW1) would be found in Marwaris and Kathiawaris. There are certainly horses that have the right kind of pattern. I had hoped that the test on the blue-eyed tovero Marwari above would come up positive, but she was negative. It would have been better if we could have tested one of the horses with the classic pattern like those linked, but it is not a breed with a lot of representatives in the West, so I was tickled to have any blue-eyed horse to sample.

This test coming up negative makes me wonder if those are homozygous splashed white-1 horses, or if there is another mutation that truly makes the same pattern. The Bald Eagle horses at least have some visual differences. I had a particular interest in seeing if the classic pattern (SW1) was in the Marwaris or Kathiawaris because they are so far removed from the breeds where classic splash was first documented. When Valto Klemola found and named the splashed white pattern (what would eventually be splashed white-1) in 1931, he believed it originated in the northern European breeds. It certainly is more prevalent in those breeds than anywhere else except perhaps the American breeds. Finding it in such a genetically distant breeds like the indigenous horses of India would be really interesting, since it would suggest this particular splash mutation is very old.

My friend’s blue-eyed mustang Jag also tested negative for all three splashed patterns and for frame. He has been pictured on the blog before, but here he is again.

It will be interesting to see how many of these horses have splash-type mutations (MITF or PAX3), or if they have unrelated mutations that also happen to give horses blue eyes.


As I posted briefly yesterday, the new paper on splashed white had a lot of surprising information, not the least of which was the horse pictured in yesterday’s post. A number of people wondered about his identity, and most particularly about his breed. His name is Apache du Peupe, and he is a four year-old Freiberger. The Freiberger is also called the Franches-Montagne, which sometimes leads to confusion. The horses in the picture above (courtesy of Wikimedia Commons) are quite typical examples. Freibergers are among the last of the European light draft breeds, though in more recent years many breeders have focused on a slightly lighter riding type, which is why I choose to shift them – and a few others, like the Frederiksborg – to a later volume rather than include it in the draft and coaching breeds.

Because they were originally included in the upcoming volume, I had looked into the range of colors in the breed. Apache came to my attention during that time. Freibergers were already interesting because they had a well-documented family of dominant whites. Those trace back to a white mare, Cigale, born in 1957. She was the source of what eventually became the first formally identified dominant white mutation. Hers is the mutation that got the designation W1. That is what I thought Apache was, until I realized that he was not related to Cigale. In fact, his parents did not look all that different in color from the two horses pictured above.

Here he is again, from yesterday’s post:

This is his sire, Noble Coeur. This is his dam, Muscade. Both are clear bays with socks and minimal face markings. Apache and his parents are the kind of horses that sat in my “don’t fit the theory” file when I first wrote about maximum sabinos (sabino whites) in the 1990s. The horses that did fit that theory turned out to be Sabino1, the spotting pattern that results in a white horse when homozygous. All the horses that fit the theory had parents with a high number on my ranking scale for white markings, while most of the horses in the “don’t fit” file had parents that fell short. Typically they did have some white, but it was a stretch to say they were marked like the others. Had Apache and his parents come along at that time, they would have ended up in that same file. Many of the horses there (R Khasper, White Beauty, Puchilingui) were later identified as dominant whites.

So I wondered if Apache was another new dominant white mutation. But there was another aspect to him that made me wonder, and that is why – up until yesterday when he appeared in the splashed white paper – he was in my “mystery” files. If you look closely at his picture, he looks diluted. If he were a Paint horse, or almost any other American stock or gaited breed, I would assume he was buckskin. Here are more pictures that give that impression.

Cantering (with is spin visible to show no dorsal stripe)
Conformation (quite current, shot in 2011)

That was what was so unusual about him. His parents are, as the links show, quite ordinary bays. And even allowing for the fact that he probably has a good portion of white hairs mixed in his coat, the tones give the impression that the actual hair is diluted. His owners called his unusual color “macchiato”, for the coffee drink, which suggested that he was cream-colored in person. Since his parents were not diluted, and since I had no evidence that cream (or any other dilution) was present in the Freiberger, I wondered about the accuracy of his pedigree. Pattern mutations do appear, but a pattern and a dilution all in one horse?

And now with the publication of the splashed white paper, we know that is exactly what he has: a mutation that is both a dilution and a white pattern. Researchers parent tested him using 13 markers, confirming that he really was the offspring of the parents of record. What’s more, they tested blood, hair roots and sperm to rule out mosaicism. Mosaics are animals that have two separate sets of cells with different genetic coding. Horses that are patched with black and chestnut, for example, are mosaics. Apache is, genetically speaking, all one horse with the same genetic makeup throughout his body. They also looked at the genes currently known to produce dilutions, and found nothing out of the ordinary. So he’s not a cream, a silver, champagne, pearl or dun. He is what is called a de novo mutation – something new.

The new thing that he has is a mutation at the same location as splashed white, which is the MITF gene. The color Apache’s breeders named Macchiato is a form of splashed white. Technically that makes four identified splashed white patterns, although researchers declined to name his SW4, perhaps in deference to what his breeders were already calling the color. So far the other MITF mutation for which we have numerous examples to study, SW1, does not seem to have the diluting component. The third, SW3, is said to be rare and none beyond the two horses pictured in the paper have come to light so far. Neither of those two horses appear diluted, but two is not a lot of data, especially when one is too white to really evaluate base color on anyway.

But what is interesting is that Apache’s mutation has a human equivalent. The human Tietz Syndrome is caused by a similar mutation. The Office of Rare Diseases Research describes Tietz Syndrome this way:

Tietz syndrome is a genetic condition characterized by profound hearing loss from birth, fair skin, and light-colored hair. This condition is caused by mutations in the MITF gene.

A second human MITF mutation causes Waardenburg Syndrome. Again from the Office of Rare Diseases Research:

Waardenburg syndrome is a group of genetic conditions that can cause hearing loss and changes in coloring (pigmentation) of the hair, skin, and eyes.

So a similar mutation in human beings causes pale hair, piebald patches (in the Waardenburg Syndrome) and pale eyes. It also causes deafness, which was also true for Apache, who tested to be deaf.

That raises the question of whether or not other as-yet-unidentified splashed white patterns might not have a dilution component like that seen in Apache. Certainly several of the horses from the Bald Eagle line have a very similar base color to Apache du Peupe. I had assumed that, being stock horses, the were getting their diluted color from the other parent. It would certainly be worth looking at the members of that family to confirm that those with diluted base colors actually had a diluted parent. That isn’t something that ever would have occurred to me to look for, because “dilution” and “white pattern” were completely separate categories of colors up until yesterday. As I said, it is an exciting time to study horse color, because there really is something new to learn all the time!

So that’s three of the four mutations. Someone probably noticed that one got skipped. That is SW2, and if Macchiato complicates how we categorize mutations, that one complicates how we are naming them. I’ll open that can of worms in the next post!

The long-awaited splashed white paper has now been published in PLoS Genetics. The full article can be read here.

As a number of people predicted, the MITF gene is involved, but there are also some surprises. One of them is that the authors looked into the odd case of the Freiberger stallion, Apache. Above is his picture from the paper, and the link from his name will take you to a site with more pictures. His owners called his odd color and pattern “macchiato.” He’s been in my “mystery” files since I first stumbled across him a year or so ago, so I was tickled to see that he was included in the paper.

It will take me a day or so, but I will try to put up a plain English summary of the paper. It is an exciting time for those of us interested in animal coloration!

More information keeps coming in from the new Splashed White tests being offered by UC Davis. Horses that have tested positive for the second version of the splash mutation (SW2) have been identified. Only a few have been made public,  but links to those have been added to the Splashed White Project page. So far the positive results have been consistent with the rumor that the SW2 mutation is present in the Gunner line of Paint Horses.

For many, the biggest surprises with the new tests have been how many horses have tested negative. I had suspected that might happen, because I knew that blue eyes were not a reliable indicator that a horse could or would produce the classic pattern. Finding horses without the classic pattern testing negative was something I expected. What I didn’t expect at all was to find horses that tested negative with the classic pattern. And now that is exactly what has happened.

Those that have read Jeanette Gower’s book Horse Color Explained may remember the Australian splash line of Bald Eagle. Several horses from this family are pictured in the book, and more can be seen at the Dunsplashin Stud website. They have classic splash patterns, but so far they have all tested negative for all three genes. What is even more interesting is that, speaking to breeders, it is clear that this particular family show this pattern with just one copy of their gene. Unlike the SW1 mutation, which presents as a classic pattern when it is homozygous, the Bald Eagle horses have the classic pattern – and produce it – with only one gene. One breeder stated that it was thought that the color was homozygous lethal, which is what is thought to be true of SW2 and SW3.

With each new pattern test, it becomes more clear that there are a lot more pattern mutations that previously understood. Because the Bald Eagle line is a sizable family, it seems likely that their mutation – which may be unique to them – will be identified in time. But the discovery that they look so much like the SW1 horses, yet have some other mutation, is another sign that we probably have a lot more patterns than was previously thought, and a lot of them probably look a lot alike.

I am still playing catch-up with the Splash Project page, with more homozygous horses (like this Paint mare owned by Julia Lord) to add, as well as links to some interesting negative tests. I did not realize that an unexpected week away would put me quite so far behind!

Until I am caught up, there are a few important bits of news. A few horses have surfaced that have tested positive for one of the other versions of splashed white, SW2. One can be seen here. Reports are that she is SW1/SW2. It has also been rumored that the Quarter Horse stallion Colonels Smoking Gun carries the SW2 version. Whether his is the only line, or if there are others, is not yet known. So far I have not heard of a horse that has tested positive for SW3. Hopefully some of those will turn up soon.

It is interesting to note that the linked SW2/SW1 mare has somewhat less white on her body than the horses that have been testing homozygous for SW1. That will be something interesting to watch for among the horses that have a combination of two different versions. Even though their basic look might be the same, as has been reported, there may yet be visual differences that people good at pattern identification may see.

And that brings me to my own limitations. I have said that I am a phenotype researcher; I look at and analyze the visual appearance of horses. I look at a lot of horses, and I study family groups and trends within them, but I am not a molecular researcher. I have had what amounts to a crash course in the molecular end of this subject in the last ten years or so, because it has become increasingly relevant if one wants to grasp the current research. But it goes without saying that at that level, there are gaps in my knowledge. And I will likely never be as comfortable with that part as I am with determining tonal and pattern differences. So be aware, when reading this blog, that I am first and foremost an artist by trade.

I try to keep that limitation in mind. It is very important to me that this blog not perpetuate bad or misleading information. I have tried to simplify concepts presented here, because most readers are either artists or breeders or owners, but simplification itself can be misleading. I’ve been told that this is the case with the “one slot” explanation for KIT mutations. I was fortunate that someone with far more background in the technical end of genetics was able to point me to some relevant research, and hope to post a clarification in the near future. For the moment, though, let me throw down a marker that the subject of KIT mutations is more complex than that.

I also have questions about the nature of alleles, which others have expressed in other venues. The question I have had is whether or not these different versions of mutations (like SW2 and SW3) occur independently of one another, or does the original mutation get altered as some point. That is, was there one splashed white (presumably SW1 since it is most common and occurs in very old breeds) that changed into SW2 and SW3? Or did completely new mutations occur in the same general area and affecting some of the same functions? Since each dominant white mutation was like that – separate instances of similar mutations – we know that the latter scenario can happen. Is that what usually happens?  Knowing this might tell us something about where to expect – or perhaps where not to expect – the less common (and perhaps as-yet-unidentified) versions of splash. I hope to send out some queries along those lines, and report back what I find.


Like I mentioned in the previous post, I became an avid collector of any examples of splash I could find. One of the most interesting “finds” I made was this particular foal, April’s Spumoni.

She appeared in the American Tarpan Studbook. I should caveat the title with the statement that while these horses were called “Tarpans” at the time, in actual fact they were not exactly Tarpans. Authentic Tarpans have been extinct since the last one died in a Russian zoo in 1909. Here is the last known photo of a living Tarpan, taken in 1884.

The Tarpans in the book are more accurately called Heck Horses. They are so named for the German biologists, Heinz and Lutz Heck, famous for their theory that extinct animals could be recreated by back breeding. That is, they felt that the genetic material that remained in domestic descendants of the original horses could be concentrated through selective breeding, until something approaching a true Tarpan was obtained. In addition to the Tarpans, they attempted to recreate the extinct Auroch.

The work of the Heck brothers is very controversial. The projects, which were conducted at the Tierpark Hellabrunnin in Munich, are often said to have been Nazi-funded. But perhaps more importantly from a genetic standpoint, there are problems that extend beyond the initial premise, which was itself controversial from the start. Questions remain about just how accurate was their understanding of the animals they were trying to recreate. (To be fair, the existing information they had to work with was itself questionable. The Tarpan pictured above, for instance, is thought by some to be of questionable origin.) It is also said that their research was not transparent; the details of what crosses were used were not preserved. Lacking modern molecular tools, they were also limited to what they read in historical accounts, and what they could see in the (alleged) domestic descendants.

Those are a whole lot of qualifiers to say that the little filly at the top was not really a true Tarpan, and may not have actually had any Tarpan blood in her makeup. It would be a mistake to say that she is proof that splashed white originated among the Tarpans, and made its way from there to domestic animals. Not when two of the breeds believed to be utilized by the Heck brothers were the Icelandic and the Gotland, both of which have modern individuals that have tested positive for the SW1 mutation.

But her situation does have something potentially interesting to tell us about splashed white.

I was surprised to find a splash in that stud book, to say the least. Her minimally-marked parents were even more puzzling. At the time I obtained my copy of the studbook, most of the splashed white horses I had found were from American breeds (Paints, Saddlebreds) or Welsh Ponies. I had not even begun to suspect that the pattern was incompletely dominant, and I had not yet encountered Gotlands Ponies and the way the patterned appeared among them. (I had seen and handful of Icelandic individuals, but was not able to track their backgrounds.) April’s Spumoni was a puzzle, because her parents were so minimally marked. They were both marked with white, which was why they both appeared in the Appendix of the studbook. Her sire had one white coronary band and a small snip. Her dam had a tiny star and a small snip. If Gambling Man has parents that left me scratching my head because I couldn’t figure out which was the culprit, Spumoni was puzzling because I could not imagine how either could be the culprit. They had “ordinary” markings.

That was close to 20 years ago, when I still imagined that there were “ordinary” markings. Markings that did not mean anything. Needless to say, I gave that idea up some time ago. Markings, and what they mean, is the question that drives most of my personal research these days. Back when I first encountered Spumoni, I wondered whether something was tamping down the pattern on her parents, or whether something was amping up the white on her. Initially I overlooked the possibility that it could very well be both, and that the range of patterns out there were being subtly altered by all kinds of boosters and suppressors.

Which is why I think Spumoni is all the more interesting in light of some of the most recent tests. I had noted in the past that some of the seemingly homozygous splash horses (what we would now assume to be SW1/SW1) had parents with almost no white. As more horses turn up with really conservative parents, it is interesting to ask just how minimal can a heterozygous SW horse be when no white boosters are present. It is certainly true that some of the Gotland parents are quite minimal. What was true about Spumoni is that she came from horses solid enough to pass for the regular register, which required that horses be unmarked. Her parents were marked, of course, and that placed them in the Appendix. All four of her grandparents, though, were registered as unmarked. In the cases where photos are available, the individuals look truly solid. Spumoni also had a full sister that had white feet, and her sire had a full sibling with a blaze and socks. All these horses trace back to unmarked horses. It is possible, of course, that the zoos involved misidentified the horses when compiling the studbook. (The early horses were all the property of zoos.)  Still, it was a small breeding community, with a small group of founder animals, so it seems unlikely that several of the more influential founders were falsely described as unmarked.

As more horses are tested, we may find out just what those outer limits are. The idea that we may start getting clues about what causes markings on horses is very exciting. That is the big puzzle, after all.

I have gotten a number of messages lately that have made me realize that it might be helpful to clarify the term Classic Splash. I began using that term in place of the commonly used “obvious splash” when I realized that if there were differing views about what was and was not splash, the word ‘obvious’ was probably not particularly instructive. If there is one thing modern testing is teaching those of us who love white patterns, it is that very little is truly obvious! I still needed a way to indicate that I was talking about something very specific, so I opted for the word classic because what I had in mind was very much in line with the pattern as it was described in the original paper by Klemola.

That was not my first exposure to the splashed white pattern, though. Credit for that goes to the pony in the picture at the top of this post. Sometime in the early 1980s, his picture was used to illustrate the entry for the Pinto Horse Association in Western Horsemen’s annual all-breed issue. I was fascinated, because I could not figure out which pattern he had. That particular photo was taken of his other side, and was angled such that it appeared that the dark area of his coat did not start until well after his poll, while much of his neck and body were colored. To someone used to looking at ordinary tobianos and overos, he just looked wrong. Very appealing, but very much like an artist who did not know what they were doing made up his pattern. Needless to say, he went into my artist reference files.

I didn’t know what he was until a few years later, when I acquired a copy of Dr. Sponenberg’s book, Horse Color.  He had a small paragraph about Splashed White, and photos of a Welsh Pony foal with the same kind of pattern. The Klemola paper was included in the bibliography, and that provided still more information and a few more pictures. From that point on, I began to collect images and background information on anything with a similar pattern. Like most artists, I have always collected large quantities of reference images, but my interest in horse color – and patterns in particular – had become a hobby unto itself. All the white patterns interested me, but none so much as the elusive Splashed White.

My early reference files are filled with advertisements torn or xeroxed from magazines. This gave me a better idea of the range of expression to the pattern, but still the information was limited. I knew that other patterns, like sabino, could occur in such a minimal fashion that the average person did not realize the horse was a pinto until it produced something more extensively marked. If that was the case with the Splashed Whites, it was often a rather big jump from minimal parents to really loud offspring. With sabinos, I could often pinpoint where the color was likely coming from in the pedigree. With splashes, it was often not especially clear. Here is Gambling Man, one of the better-known of the Splashed White Paint Horses from the early 1990s.

Those are his parents in the inset clipping. So did his color come from his sire, with his blaze and four white feet? Or maybe his dam, with her irregular face marking that covered her nose? My files were full of horses like this, where it was impossible to narrow the source of the color down even to one side of the pedigree. Of course, this was also before the use of the internet was widespread, so there were no online databases or easy access to images, so often the background information was incomplete.

It was actually the format that I used to organize my files that led to the realization that Splashed White was probably incompletely dominant. I always entered horses into my notebooks with as much pedigree information as I could find, because I was usually looking for the color line. That is, I wanted to know where the color came from so that I could more easily rule related horses in (or out) for a given pattern. When color printing became feasible, I began color coding the names to note whether or not the horses in the pedigree were known to have a color or pattern, were suspected of it, or could be ruled out. What made Splashes so maddening was that I couldn’t even rule out one side of the pedigree on any of the entries. It took a while, but eventually I realized that wasn’t the problem; that was the answer. I couldn’t rule either side out because it came from both sides.

After that, the color began to make a lot more sense. The pattern did not occur on a continuum, like sabino appeared to do. It often did not look like much until the horse inherited it from both parents. That was why I sought out that very specific pattern as “proof” that Splashed White was there. Anything less went into my “maybe” files. I did that because over the years of searching for these horses, I found that some things that looked promising often ended up as dead ends. (Conversely, the horses that actually produced classic splash patterns often looked anything but promising!)

As I mentioned in previous posts, I have classified two sorts of “False Splash” patterns. I should caveat that by saying that it wasn’t that horses with these types of patterns could not have splash. In breeds with multiple forms of white patterning, splash carriers might well look like these horses. But they could also prove to be quite disappointing. That caused me to be rather cautious, because I could not be sure that these horses weren’t carrying something entirely different. Here are some clippings from my files of the two types:

These are horses where the bottom part of the pattern – the legs and the underside – look a lot like splash, but the white on the face is more like sabino. That is especially true for the Arabian pictured, Raffon’s Abida. Horses like this don’t usually have blue eyes, nor do they usually produce many blue eyes.

This is the other category of misleading horses:

These guys have the right kind of face and the blue eyes, but they don’t have the body white. Their tails are usually dark, too, whereas Classic Splashes tend towards white tail ends.

Horses marked like these are not always disappointing. Sometimes they do produce Classic Splashes. My personal suspicion is that this second type is what Classic Splash (suspected SW1) looks like in its heterozygous state when paired with a white-boosting mutation like sabino. In breeds like the Paint, where white-boosting genes are consistently found, this is what a lot of horses from splash-producing families look like. In breeds where those kinds of patterns are rare or non-existent, heterozygous horses do not seem to look like this.

So some of these horses probably are splashes. That said, I could never be sure that some other combination of white patterning might not also create this kind of look. That was because horses that looked like these pictured above sometimes occur, but they do not produce the classic pattern like the ones seen on the horses at the beginning of this post. It might be that they just haven’t been bred to another carrier, or that the odds haven’t worked out in their favor. But absent a test, I have reserved judgement, just in case it was something else. While it is possible to say something is associated with this or that pattern, there are enough gaps in our understanding that it is hard to know how exclusive those characteristics might be. It is quite likely that there is overlap between the different patterns. My great hope is that the new tests will begin to clear some of that up, even as they raise new questions.

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