Ow

Is this a treat, mom?

Well, my attempt to tape Justice's height says he's 13.3hh.  Give or take an inch in there for wiggly baby, my first time trying to use a tape, and wind.

He's just starting to encroach in height on the older of the two full draft babies he shares a pasture with - and on the three year old that's herd boss.  Rough eyeball says they still both have at least a hand on him, but he's gained at least two inches over the winter.

And the ow?  Yeah, um.  Somebody forgot to watch their fingers while feeding treats to the babies and miiiiight have been bitten on the finger by her mare's most recent foal.  Maybe.  *cough*

Circling back to the weird stuff

This is kind of a catch-all post.  There are lots and lots of things about horse color that we still don't know what's creating them and why, so it's hard to categorize!

Dun
I did end up going back to do a little research on the dun/non-dun thing I talked about briefly. And it turns out?  It's not that funky after all.

Basically, what they've determined is that dun seems to have two versions.  One version is traditional dun: diluted body, dorsal stripe, primitive markings.  That's still marked as D in genetic testing.

The second version is just the primitive markings and dorsal stripe, without the dilution to the rest of the color.  It sounds, reading between some lines, like this might be the cause of the countershading that makes people think they must have a dun when they don't.  That's nd1.

And "off" - no dun, no primitive markings - is now nd2.

Examples of the three genes from the original paper.

They've also determined an order of how these get applied.  D and nd1 seem to be dominant, but something has to take the lead, right?  It goes nd2 => nd1 => D.  So if you've got a horse that's nd1D or nd2D, they're dun.  If you've got a horse that's nd1nd2, they've got primitive markings.  Neat!

Examples of non-dun 1 combinations, from the original paper.

Sooty
I kind of blew past sooty when talking about coat colors, because it's definitely one of those nebulous things.  They've done some research on it, but haven't discovered what actually causes the effect yet.  One piece - a German study on some Franches-Montangnes horses - suggests that whatever this sooty/darkening gene is, it may be recessive rather than dominant.  (I'd link the article, but - German.  I'm all for useful links, but not if I don't know what it actually says!)

Sooty as a concept describes a horse whose coat is generally darker along the back and spine, and who may have a darker area on the face almost like a mask.  It tends to produce dapples.  It might also produce countershading, but given the nd1 - well, who knows right now.

Example from Wikipedia.

But, just to make things more exciting, sometimes sooty works from the hooves up.  Not every sooty horse has dapples.  There's even a floating theory that sooty - which isn't generally uniform - might be at least partly responsible for liver chestnut.

Sooty tends to have a striking effect on buckskins (as the photo above) and palominos, but it can show up on pretty much anything except black.

Pangare
Pangare is the other one I kind of blew past.  It's also sometimes called mealy - as in, mealy muzzle.  Horses with pangare will have lighter color around the muzzle and belly; the light color can extend up into the flank and behind the elbows, and sometimes up the throat.  Some horses even show lighter color around their eyes.  What "light" means depends on the horse; it ranges from off-white to light tan, generally.

Pangare only seems to show up on chestnuts and bays.  Blacks don't how it at all except when they're foals, and that's only on some and only until the foal coat sheds.

Haflingers.  PERFECT example of pangare - seriously, just google Halflinger horse.  Photo from Wikipedia.

Again, it's not something they've determined what the heck causes it.  Unlike sooty, they don't even have the most basic of studies to suggest a sort of maybe way it might be inherited.  It's just a thing that happens, and it shows up in some breeds more than others.  Halflingers, Belgians, Fjords, and Exmoor Ponies can all show up with it.  It's actually thought that it may be something present in pre-domesticated horses, as it shows up in the Przewalski's as a general rule - and in a lot of the non-horse, non-zebra equines as well.

This page has a gallery of some absolutely stunning images.  I wouldn't turn down that draft-Fjord cross... lol

Flaxen
And the third really common one that nobody's cracked the genes on is flaxen.  They know that something causes manes and tails on chestnut horses to lighten.  How much lightening varies - it can range from barely flaxen to the obvious blonde color to near-white.

Like momma here.

Current theory is that it's a family of genes, since it's definitely an inheritable thing.  The first look at the issue (a study done on Morgans) suggested a recessive inheritance pattern to basic flaxen, but two barely-flaxen parents can (but may not always) produce horses with near-white manes and tails, so clearly something else is going on too. 

Gulastra Plume
Also known as silvertail, this is when an otherwise dark bay horse turns up with a non-black tail.  I say non-black - descriptions and photos range from silvery black to actually white.

Donatello, borrowed from White Horse Productions' page.

The name "Gulastra plume" comes from the Arabian folks.  A chestnut stallion named Gulastra threw these pale tails over and over again on his bay foals, although he himself didn't actually show it.  It's not limited to Arabians, though; it can crop up in Thoroughbreds (as with the image above), in miniatures, and anything in between (or bigger).

Looking at available images, it tends to whiten from the tip up, and it tends to blend together in a way that's unlike silver.  Equine Tapestry notes that she sees it a lot in wild bays, and that although it looks like the rest of the horse is unaffected, it's not unusual to see a sprinkling of lighter hairs in the mane and silvery heels (if there are no interfering white markings).  She also points out, though, that "wild bay" isn't strictly defined, because it's a term for how the horse looks and not a true gene, and that the silvery tail isn't restricted to that appearance.

So what is it?  Nobody knows.  Early theories speculated it was rabicano, but rabicano puts in white from the top.  It could be related to wild bay; it could also be a sabino or sabino-like pattern, which is what the Morgan folks seem to think.  It's not sabino-1, though; Gulastra plume Arabians have been tested for that and came up clear of that gene.  It kind of resembles splash, in that it's coming up from below, but isn't necessarily linked with the kinds of other white markings you typically see in splash.

Birdcatcher, Chubari, and Bend Or spots
These spots are another small genetic mystery.

Birdcatcher spots are small white spots - usually smaller than 1 inch - that randomly appear (and sometimes disappear) on a horse's coat.  They often show up later in life, and may have roaning to them; in fact, the horse may also have a very small amount of roaning around the flank and tail.  It's more common to see them on chestnuts, but they can and do appear on any color.

Example from Equus Magazine.

The name comes from an Irish-born Thoroughbred in the 1800s named Birdcatcher.  How it gets passed on - or if it does - is still a mystery.  Some believe it gets passed on along family lines, but others think the marks are just white hair growing in from some injury.  Equine Tapestry thinks it's a combination of both (and totally follow that link; it's got some cool stories in the comments), but nobody's done any research, so it's hard to tell! 

Chubari spots are also sometimes known as Tetrarch spots, after The Tetrarch, a grey Thoroughbred born in 1911.  (Some neat info on him here.)

The Tetrarch, from White Horse Productions' page.

Like the birdcatcher spots, these are also white - but they're much bigger, tending to run more to the egg-sized and -shaped range.  Unlike birdcatcher spots, they seem to only appear on grey horses.  Unlike the weird dappling that grey can show, they only disappear when the horse has greyed out completely.  The Tetrarch is unusual because he has so many; it's much more common to see only a few.

Again, there hasn't been any sort of study on chubari spots.  We know The Tetrarch passed his spots on to some of his foals, and many TBs and horses with TBs in their breeding that show up with chubari spots will trace back to The Tetrarch somehow - but it's not limited to Thoroughbreds, either, as far as anyone knows.

Bend Or spots, unlike the other two, are dark spots - ranging from slightly darker than coat color through to almost black.  They tend to show up on red-based horses more often than bay or black, but have been known to show up on bays as well.  Like chubari spots, they tend to be on the larger side and tend to just kind of stick around once they show up.  (Interestingly, The Tetrarch is said to have shown chubari spots before he really started greying out.)

Example from Wikipedia - enlarge and look at his flank and gaskin.

The name comes from an English Thoroughbred stallion named Bend Or, born in 1877, but the spotting likely comes from one of his ancestors.  The Thoroughbred Heritage site notes that his ancestors Pantaloon (born 1824) and Comus (born 1809) both show the same spotting. Bend Or's grandson Man O'War was said to have Bend Or spots too, but I have yet to find a picture that shows one - both because most of them are in black and white or tiny and because it seems like people only took photos of his left side!

Again, we can see that there's a tendency to pass it down, but nobody knows what's causing it.

Bloody Shoulder
"Bloody shoulder" refers to an area of not-grey on a grey horse.  Even as the horse turns gradually whiter, these areas will stay dark - and the dark area may actually grow after the horse whitens out.

Charmander, TB mare.  From White Horse Productions.

It's not limited to the shoulder, although that's a common presentation.  It's also most commonly found in Arabians, although a few Thoroughbreds have shown up with it as well (not surprising, considering the Arabians way back in the family tree there).

An Arabian example - Sweet Meadows Sanaya

And again we have something that's happening that it isn't clear what caused it.  Some speculation is that it's a chimeric mutation - that the horse had a non-grey twin that was absorbed.  Whatever causes it, it's striking!

The many shades of chestnut
Chestnut's a pretty basic color, right?  I mean, sure, you've got your liver chestnuts, but red is red.

From The Equinest

Yeah, about that.

Borrowed from Equine Tapestry, but viewable many other places as well.

That's a Black Forest Horse, and you'd think that's a silver black, right?  Nope.  They did a study on all of the stallions standing at stud at the time, and every last one of them was genetically chestnut.

And then there's sorrel.  Sorrel cracks me up, because it's a very Western-riding-world term that basically just means chestnut.  Even AQHA will accept either.  That said, I know I have a very specific idea in my head of what gets called sorrel.  Maybe I'm weird?

Brindle
Brindle is a really weird one.  There are two types of brindle.

One is not inheritable.  It's just a random chimeric mutation - normal mom, normal dad, hello random stripey baby.  Usually the stripes are dark, but White Horse Productions has images of some awesome white-striped brindles, including the stallion Catch a Bird, who sired some roan foals when roan wasn't previously known to happen in TBs.

On the other hand, there apparently now really is an inheritable brindle pattern?  Most of the information I'm seeing comes from just one site, Justa Brindle Horse Farms.  She's got some cool examples and she's got some examples that I mostly just frowned at and scrolled on past because I couldn't see much.  It seems like this stripey pattern is coming from a mare called Ima Star Moon Bar, and it's got some seasonal variation that means it's not always that visible.  I'm not seeing much of anything outside of that one site, so YMMV.

Other dilutions?
In Shetlands and Halflingers (and maybe a QH or two), there's a color called "mushroom."  It visually looks a bit like silver black, but the Shetland examples that were first tested tested not only don't have silver - they're actually chestnuts.  They're typically born a pale beige with a pinkish or greyish tint and generally retain that color into adulthood, although some darken.  It's believed to be recessive, although nobody's figured out what gene is causing it yet.  I couldn't find any good not-on-Pinterest, clearly-marked-with-a-copyright pictures that I felt good about borrowing and the ones on Wikipedia are odd, but it looks like the definitive resource for Shetlands is this page from Kellas Stud in the UK, which has some great pictures.

Morgans have what's looking like it might be a new dilute gene, described here.  It's been described as "light black," since it affects primarily black hair (instead of red) and seems to turn genetically black horses brown.  It also seems to be recessive.  There's a similar "light black" that's been found in a pair of Arabians (Mireyenion Tos and Ali-Zeus), a Friesian (Nico), and an Australian Quarter Pony (Mia).  The ones that have been genetically tested have tested negative for all known dilutions, per Equine Tapestry and some of the other links. 

Other Oddities
W21 looks like it might be coming from Icelandics again, with another sabino-type pattern and possibly blue eyes. 

There are two other horses that have tested as genetically buckskin, but look more like double-creams (or cream/pearl).

And I'm sure there's lots more that I haven't turned up with a quick googling!



Additional resources
I'm definitely not the expert on horse color genetics!  I rely a lot on information from the following places:
The Appaloosa Project
Equine Tapestry
New Dilutions

But I've also got some books lying around too.  :) 

• The definitive book is really D. Phillip Sponenberg's Equine Color Genetics (Amazon link to the latest version, but mine is an older version simply called Horse Color) - but I have to say, if you don't understand a little about genetics, it's an overwhelming amount of information that's hard to follow and digest and a bunch of neat pictures.
• Horse Color Explained (Amazon link) is a little bit dated these days, but it's very good at breaking things down into manageable, understandable, at-a-glance chunks.
• Equine Tapestry has two books out: the older The Equine Tapestry: Volume 1 - Coaching and Draft Breeds (Amazon link) and the newer The Equine Tapestry: An Introduction to Colors and Patterns (Amazon link).  I've got the first, but not the second.  The writing style is very similar to what you see on her blog - readable, thoughtful, not too deep into the genetics except as needed to explain basic concepts.

Puddles and flowers and silver

I didn't go hang out with Cessa today because she was at the back of the freaking pasture and yesterday was crappy as hell, so my level of energy was low.

However, I did go see the little guy!  We stood in a puddle:

We were not impressed by the puddle. Try to walk around, sniff, step over.  He almost hopped once?  Then we stood in it.

We cataloged new white fur:

Funny jaw spot. It vanishes when he picks up his head, and it's not missing fur - it's actually white!

We joked with his breeder that she's not allowed to braid his tail anymore:

On the left: last week.  On the right: this week.  These photos don't do the change justice!

We explored the front pasture:

Hi, Justice!

With one of his year-mates - I swear I wasn't trying to hide him!

And wore flowers in our hair:

I can haz flower?

And most importantly, he reminded me very much of why he was a smart horse to buy.  Baby's got a good, calm mind.  Everybody else running around?  Meh, I guess I can trot.  Human flapping at him to get him to move away from something?  That means you're going to scratch my butt, right?  Walk down the driveway with just a human for company?  Sure, okay, can I eat more grass?

Dominant white/white spotting

"Dominant white" refers to a large group of genes that produce white spotting in various individuals and breeds.  It's actually one of the areas where they're doing a lot of research, so new dominant white genes are added to the list fairly often.  I'm not sure why everyone's saying suddenly, "Oh, it's white spotting, not dominant white," so I'm gonna stick with the name I learned it was for now.

The expression varies both from horse to horse and from gene to gene; some patterns look like sabino and others produce pure white horses.  But generally, the following things are true:

• Inheritance is dominant - one copy turned on and you can see the pattern.
• All of them are coming from the same areas of the DNA, so they're grouped together and it's assumed you can only inherit one dominant white gene from each parent.
• No horses have been found that have the same dominant white version turned on twice, so it's assumed that they are lethal at the embryo stage.  (There is an exception, which I'll call out.)
• New dominant white genes occur as random mutations, so they often appear suddenly and can actually happen in any breed.
• Eye color isn't usually affected, so unless there's another pattern or coat color acting, the horse's eyes will be normal brown.
• Skin is pink under the dominant white pattern.
• Some versions are a sabino-like pattern, and there's a lot of confusion between sabino and dominant white.
• In version where the horse is mostly white, but still has color, that color tends to be concentrated along the topline, especially the mane and ears.  There may also be roaning or interspersed spots in the white.
• Hooves tend to be light-colored.
• Mostly white horses can sometimes lose the non-white hair over time, eventually turning entirely white.

In the genetic test results, it's generally shown as w (off) or W1-W20 (on, for whichever one you've got).

Yeah.  20.  Maybe more.  I'm going to pull pictures where I can, although of course some of them are just going to be a white horse...

White-1 comes from the Franches-Montagne or Frieberger breed, and specifically from horses descended from the mare Cigale, who was born in 1957.

From the identifying paper, loaded on Wikipedia.

Horses are generally born almost white, and can lose what pigment they have as they age

White-2 is from Thoroughbreds.  They descend from a stallion named KY Colonel, born in 1946.  He's described as having high white stockings and a belly spot, much like a sabino, and passed those genes on to two of his foals.  One, War Colors, was registered as a roan but failed to produce any foals.  The other, White Beauty, passed down her white color to a line sometimes referred to as the "Patchen" line, after the mare Patchen Beauty.

White Beauty, borrowed from here.

According to The Blood Horse, one of the latest generation is Chief White Fox, and it looks like he has some cousins and half-siblings out there.  That said, it's still a small, rare line.

Some presumed W2 horses - War Colors being a great example - have been registered as roan or grey, but the "typical" presentation is all white, just like White Beauty.

White-3 comes from Arabians.  When I was talking about sabino in Arabians, this is one of the genes I was thinking of that isn't sabino, but (confusingly) is called sabino by the Arabian people in a lot of the information I've looked at.  It comes from the line of R Khasper, a stallion born in 1996.

R Khasper, from his owners' page on him here.  Looking good at 18 in the photo!

W3 shows up as high whites and belly spots - or more, all the way up to mostly or all white.  Looking at him and his foals, if there's color on the highly expressed horses, it's tending to congregate around the ears, the base of the tail, and in a downward-pointing triangle on the back between the haunches and withers.  There's a lesser degree of color along the neck, as well.  This is generally true of a lot of the sabino-type dominant whites, but that one triangle was just particularly striking to me!

White-4 is found in an entire breed, the Camarillo White Horse.  It all stems from a stallion named Sultan, foaled in 1912.  According to what I'm seeing, he was a Spanish Mustang, but was crossed to Morgans to form the beginnings of the breed.  Since the white coat is so characteristic of the breed, they do have an open studbook so they can cross out to non-white horses and maintain the color.  (Remember, W4W4 is believed to be lethal in utero.)

And they're pretty much just white in appearance.  At most, they might have a little color along the topline.

Borrowed from Wikipedia.

White-5 is from the Thoroughbreds again, this time descendants of Puchilingui (foaled in 1985).  W5 horses can range in expression from white blazes and high, irregular socks on up to white or near-white horses.

Puchilingui, from here.

Probably the most high-profile example of the line is his son, Sato, but there are plenty of others!

White-6 was another Thoroughbred, but I can't find anything other than this:

From the original paper

According to what little I can find - and squinting at horse e that picture - it's a very roaned sabino-like type, and only one horse was tested at the time the paper was published in 2008.  Speculation points to a horse named Marumatsu Live as the horse in question, but I haven't seen anything but speculation.

White-7 is - stop me if you've heard this one - a Thoroughbred mutation as well.  Again, that one photo above is all I can find (horse f); squinting at it reveals another heavily roaned, sabino-like pattern.  The horse tested has not been identified publicly aside from stating that the dam and siblings were solid and the horse was foaled in 2005, so I've had no luck tracking down anything but speculation about who it is.

White-8 comes from Icelandics.  Equine Tapestry points to the Thokkadis family, although every other source says "unidentified Icelandic;" she does a lot of pedigree analysis to track colors, so while she has been wrong in the details of the genetics, she's generally right in the pedigree department.  Also seeing that noted on another, much more dubious source (it's a random forum, so... reader beware).  Unfortunately, searching Thokkadis and Icelandic doesn't turn up anything substantial other than a picture from the same dubious source as part of a much larger image that I cannot get to load.  Squinting at the photo strip above (horse g) reveals a white pattern that doesn't look all that different from W3 and W5, but the only other image I can find is about as big as the images in that strip and in an image that is horribly pixelated because it refuses to load.

White-9 is from the Holsteiners.  Again, unidentified single individual reported, and again about all I can do is point to that photo strip (horse h).  Similar to W8, I can see there's an alternative image in the picture that will not freaking load, but I can't say much about it.  It's white?

White-10 is much easier to find!  It's from Quarter Horses, specifically descendants of GQ Santana (foaled 2000).

GQ Santana, from here.

Looking at pictures of his foals, that dark eye is characteristic of the maximum expression; it's there in a whole lot of them.  Lesser expressions look more like sabino - high leg white, belly spots, etc.

White-11 comes from a draft breed called the South German Coldblood, and specifically seems to be from the bloodline of Schimmel.  The South German Coldblood is one I hadn't heard of before; it's similar to the Noriker, but has been shown to be genetically distinct.

I found one picture other than the lovely (if tiny) one in the photo strip above (horse l), and I'm not entirely sure where it belongs because it's on Pinterest.  It also shows what I know has to be a young draft, probably 2-3 years old and deep into the awkward stage. Poor baby.  lol

White-12 is yet another unidentified Thoroughbred, and I'll cycle back to the huge number of TBs in this list at the end, because it's interesting.  Suspect forum source says the tested horse is deceased, and I'm not spotting a picture other than the one that won't load.  (Argh, so frustrating!!)  It looks similar to W5.

White-13 is assumed to be from Quarter Horses; it was tested in a single individual or small family of QH-Peruvian Paso crosses.  Again, the image-that-won't-load is the only one I can find, and the horse it shows is... white.

White-14 is another Thoroughbred, but this one's identified!  It comes from a Japanese bloodline, descended from a mare named Shirayukihime.  Like W2, there's a lot of pure white going on here.

Yuki-chan, one of Shirayukihime's foals. From Wikipedia.

White-15 sends us back to the Arabians, and specifically to the Rhocky Rhoad / Khartoon Khlassic bloodline.

Khartoon Khlassic, from his website.

Rhocky Rhoad, from his owners' site.

Again we're looking at a very sabino type of spotting - face white, high white legs, and belly spots.  The most expressive of the foals I looked at had a huge belly spot that extended up onto her body, but most of them look closer to these two stallions.

White-16 was been found in the Oldenburg.  No word on where exactly it came from, but a horse named O' Wie Weiss went through the auctions and and is theorized to be W16 - and possibly her dam as well.

From here, linked off the CotH forum.

However, the actual line wasn't identified in the original papers, so this is only a tentative identification; the dam could easily belong to a known or suspected dominant white line (especially with warmblood lines, where they keep bringing in TBs), or this could instead be sabino-1. 

White-17 is from the Japanese Draft Horse - and again, we're sparse on information here.  It appears that there were two individuals located and tested in 2010, and the breed is known to have facial and leg white and the odd white individual, but... that's all I can find.

White-18 is from a Swiss Warmblood named Colorina Von Hof, born in 2009.  Again, there's a similarity to W5 - and again, the only freaking picture I can find is on Pinterest!  (I kind of hate Pinterest.  It's a neat concept, but it really robs all context from the images, and I'm trying to make sure that if I pull photos from somewhere other than my personal collection or Wikipedia, I can at least account for where it originally came from.)

White-19 is Arabians again, this time believed to come from a mare named Fantasia Vu.

Awestrukk, a descendant of Fantasia Vu. From his owners' site.

Again we've got the flashy sabino, but like the Khartoon Klassic lines, they don't really seem to come in white. Awestrukk there is a bit more flashy than the average, but nicely shows the pattern.  W19 horses sometimes have blue eyes, although it's not clear from what I'm seeing if that's because of the W19 or if there's a separate pattern going on.

There's also this guy, also W19:

HAAP Snowy River, from here. (Also found a source for the same photo that is... entirely in Russian... so we're gonna go for the one I know what it's saying.)

This presentation is atypical for W19, but is typical for this cross - Pandemonium River x  Fantasia Vu.  It's speculated that Pandemonium River carries an additional sabino or dominant white pattern that's adding to the white of W19.

And last but not least is White-20.  And it's the weird one that isn't lethal when two copies are turned on.

Where the others are flashy as hell all by themselves, W20 seems to be more related to simple white markings.  Copies of W20 have been found in horses that have nothing more than a blaze and some socks.

Like these two.  Borrowed from Equine Tapestry.

Looking at pictures, there are examples with even less white.

On the other hand - W20 is one of the only dominant white genes to be discovered in combination with any of the others.  When it does show up with another dominant white gene, it significantly increases the amount of white visible.

Shew of Gold GF (W5) with her white foal Supernatural (W5 and W20).  From Equine Tapestry.

There are more examples here.  It seems to be the oldest of the white genes, and has been discovered in a huge range of horses - Gypsies, Thoroughbreds, Icelandics, Minis...

Now, I said there's at least 20, and I said I'd come back to the Thoroughbreds!  There are the occasional mentions of additional W genes.  One site I looked at talked about W21 and W22, but didn't do much more than cite the name of the paper and a generic copy-pasted description of the paper itself. 

There are a couple of lines of TBs that look either dominant white or sabino, but researchers haven't identified what gene they have.  There's a mare named Turf Club who seems to have spontaneously mutated (speculation is that she's the W7 horse, but again nothing I found confirms this).

Another mare, Not Quite White, produced a stallion named Airdrie Apache that gets a lot of use as the sire of "pinto" Thoroughbreds; speculation is that she's a dominant white as well, with an as-yet-unidentified mutation.  Airdrie Apache definitely passes down his pattern, though!

Airdrie Apache, from here.

White Horse Productions calls out a few more that might be dominant white and might not.

There have been white Standardbreds that, because their parents were solid-colored, might be sabino (if the parents were minimally expressed) or might be new dominant white mutations.  And there's nothing that says there can't be other examples out there that have passed unnoticed.  Various sources I looked at call the gene where dominant white and sabino and some of the other white patterns sit "volatile" - it can and does mutate regularly.

There's also a color called manchado, which appears only in horses with origins in Argentina.  It's sometimes speculated to be environmental - although that does raise the question of why Argentina specifically and only - but it's got a wide enough distribution in enough breeds down there that some have questioned whether it's genetic, even though it can and has been reproduced down family lines.  If so, it seems to be recessive.  Equine Tapestry covers this in pretty good detail here.

From White Horse Productions.

So is manchado dominant white, despite being recessive?  Sabino?  Something else?  No one knows yet.

Ticking along to roan

Next up, roaning patterns!

Roaning is generally defined as areas (up to and including the whole horse) where the horse's base coat color is evenly mixed with white.  Unlike grey and varnish roan, the white hair is usually present when the foal is born, and generally the horse will keep the same amount of white or get darker, not lighter.  A horse with roaning may appear darker in the roan areas in winter and lighter in summer, but the amount of white isn't actually changing as the seasons do.

Classic roan or true roan is written in genetics as rn (off) and Rn (on), and it's a dominant gene - one copy shows the roaning.  The test for roan is... weird... in that it's not testing for the exact gene itself; they haven't identified it.  But they have identified some markers in other places in the DNA that indicate that whatever gene it is is turned off or on and whether one or both copies are on in certain breeds of horse.  The only public test available is for horses with Quarter Horse and Paint ancestry.

The horse's entire body will be roan, although the head, legs, mane, and tail will have much less white than the body.

Red roan. From Wikipedia.

Bay roan. From Wikipedia.

Blue roan. From Wikipedia.

The three most common versions of roan have their own names: chestnuts are red roans (they used to be called strawberry roans, which is the version I learned as a kid!), bays are bay roans (but used to be red roans), and blacks are blue roans.  From there, there don't seem to be specific names, just a color with roan after it.

I've heard that combining true roan and varnish roan doesn't go the way you'd expect - in other words, probably doesn't mean more roaning - but I've never seen an example, so I can't say for sure!

One of the other distinct characteristics of true roans is that they'll have what's called corn spots.  Those spots are places where the horse's skin was damaged somehow; instead of growing back roaned, the spots will grow back the base coat color.

The examples above are pretty clear-cut roans, but it doesn't have to be that way.  Sometimes roan is really, really subtle.

Minimally roaned chestnut, from (oh god) the second year I was taking lessons - 1993 or 1994 - so apologies for the crappy quality.  Actually makes her look more roan than I remember!

One of roan's close relatives is rabicano.  This is one of those patterns that we can see - we can even see that it seems to be dominant - but geneticists haven't discovered the actual gene for it yet.  They do know it's not the same genetics as true roan, though.

Where true roan affects the horse's whole body, rabicano affects the flank/barrel area and the tail preferentially.  It also tends to be more expressed on chestnuts than other colors, although it can and does appear on any color.

From Wikipedia.

With extreme expressions of rabicano, the ribs may be striped (as in the photo).  In minimal expressions, it may just affect the tail.  In all expressions, the white hairs on the tail - often in rings or on either side of the tail head - acts as a defining characteristic of rabicano.  It's often called a coon tail or skunk tail.

From Wikipedia.

Rabicano also tends to spread as the horse ages, and unlike true roans, rabicanos won't have corn spots.  It also shows up in breeds (like Arabians) that don't seem to have true roans.

Sabino - and the dominant white patterns I'll talk about in the next post - are just kind of fun.  It's typically notated as sb (off) and either Sb or Sb1 (on).

Sabino is actually a group of patterns.  The one identified for testing is Sabino-1, but there are sabino-like patterns in draft horses and Arabians that behave similarly but test negative for Sabino-1.

On a horse with sabino, you'll see: roaning at the edge of white areas, which tend to have jagged edges; belly spots; irregular face markings (especially blazes) that may extend past the eyes or chin; two or more white leg markings that typically extend above the knees and hocks; and roaning or random white marks ("lacy" or "splashed" in appearance) on the belly, barrel, and flanks.  Unlike splash, there is no link to deafness.

Sabino is another one that can easily be mistaken for something else - or nothing at all.  The most minimal expressions may just be a chin or lower lip spot; on the other end of things, sabino can and does produce pure white horses (and these are healthy, unlike the pure white frame horses).  I've classed it with roan and rabicano because it does have that characteristic roaning to it.

Sabino-1 is known to be incompletely dominant, like cream.  One copy of the gene turned on produces a horse with the typical sabino markings.

Borrowed from Wikipedia.

Two copies of Sb1 produces a horse that is at least 90% white at birth, with the corresponding pink skin under the white pattern.  This is sometimes referred to as sabino-white, especially when the horse is almost entirely white.

I could argue this guy as homozygous sabino or as sabino/splash.  (From a local show)

"Draft-type sabino" typically shows up in Clydesdales, Shires, and breeds related to those two (like Gypsies).  They actually included examples in the study that identified sabino-1, and none of them tested positive for that version of the gene.  What gene it is, they don't know yet, but it behaves like sabino and is generally assumed to be a sabino pattern.

A draft-type sabino will have white facial markings that range from blazes to bald faces to apron faces, which may wrap around the face and generally have feathery, roaned edges.  If they have white on their forelegs that extends above the knees, it may trail up to the shoulder or back of the leg to the elbow, again with the feathery edges.  White on the back legs, which is common, may extend up the front of the leg to the flank.  Belly spots are also common, especially when the white on the legs extends over the knees.

Very typical Clydesdale with draft-type sabino. From Wikipedia.

Unlike sabino-1, it seems like the draft version is only dominant, not incompletely dominant.  Since Clydesdales and Shires are generally a closed population (they're not registering anything that doesn't have parents of the same breed), there should be about 25% of the population that come out with 90% or more white if the draft-type sabino is incompletely dominant, and they just don't see it.  White Clydesdales and Shires are very rare.

To break down that math, assume you have a foal whose parents are both Sbsb.  Baby has four options for what gene pair it gets: sbsb (both off), Sbsb (one on from dad, one on from mom), sbSb (one off from dad, one on from mom), and SbSb (both on).  Four options, so the chance of any given genetic pair is 25%.  And with sabino-1, they see this: with two Sbsb parents, 25% of babies are solid, 50% are sabino (because Sbsb and sbSb look the same), and 25% are sabino-white.  With draft-type sabino, 25% of babies are solid and 75% are sabino.

Similarly theoretical is sabino in Arabians.  Arabians actually have a couple of dominant white patterns, but they also have white with roaning that isn't explained by those patterns; I'll go into this on the dominant white post, but dominant white is for the most part tied to bloodlines.  If a horse doesn't descend from the founder (assuming they've figured out who it was), it's unlikely that they've got the same pattern.  It's always possible that the horses showing sabino could end up being additional dominant white patterns, but for now they're classed as sabino.  As with the draft-type sabino, there's no genetic test for it yet.

As with other types of sabino, you'll see the face white, belly spots, high whites, and roaning around the spots.  The maximum expression in Arabian sabino seems to be about 50% white instead of 90%, and the few apparently sabino-white Arabians have tested negative for sabino-1.  It's not clear at this point if it's a dominant or incompletely dominant gene, as far as I can tell.

So going back to our theoretical horse, who at this point is a smokey grullo with splash, let's assume he also has sabino.  That makes him:

Ee aa CrC zz DD chch toto oo SW1sw Sb1sb lplp

It also makes him a flashy, flashy critter. lol Visually, the splash and sabino look pretty similar unless you look closely, but there's a decent chance you'd be staring at a grey horse with a black mane and tail, a dark stripe down his spine, some seriously high white stockings, an apron or bald face that wraps down onto the lip and chin (or even all the way around the face), and a jagged belly spot.  Maybe a random neck spot or two.

Next will be dominant white, which I love looking into.  I may have to split it up into multiple posts, though - there are over 20 different identified versions of it!  We'll see how much information I dig up.  :)

Classic paint

What I consider the classic paint genes are tobiano, frame (lethal white overo), and splash.

Now... the APHA would probably sort of disagree with me, because they include sabino (which I'll cover with the roaning patterns) and generally frames all colors as tobiano or overo (with subvariations of splashed overo vs frame overo vs sabino overo).  Or tovero, which... is not a thing at the genetic level; it's just tobiano plus an overo pattern.

White patterns will almost always have pink skin underneath them, which can make it fun to give a grey horse a bath sometimes.  :)  Sometimes they may have edges where the normal dark skin extends under the white, which produces a look that is apparently highly desirable in the model horse customizing craft community.  (Another random thing that I have knowledge of...)

Also of interest, if you've ever picked up a horse book by a British author (I plead the fifth on how many horse books I have, by the way) - the terms piebald and skewbald just refer to black-based pintos (piebald) and pintos with any other base color (skewbald).

And a tri-color pinto?  That's actually a bay, unless your horse has a chimeric mutation.  Chimeric mutations are when a horse had a twin while in the womb, and the two merged during development.  That's what gives you things like brindle horses (some of which are so neat to look at) and horses where part is black and part is chestnut.  This link has some cool examples.

So let's talk tobiano first.  Tobiano is dominant, so you only need one copy to see the pattern.  The edges of the white are smooth lines, not jagged - like drawing a curve vs. drawing steps.  The horse's head is generally dark with minimal markings (blaze, stripe, star); if they've got a flashy head, chances are they've got another pattern gene causing that.  In general, it's a vertical pattern - it crosses the back and tends to be very up and down along the horse's body.  I've seen it described as oval, but I have a hard time seeing that on most horses

These two are awesome examples of tobiano (from a local show).

White from the knees and hocks down is pretty commonly a tobiano thing, as is white crossing the back between the withers and tail.  Tails may also have white in them.  The chest and flank both tend to be dark, as well - sometimes the dark on the chest and neck is referred to as a shield shape, but I'm iffy on that description.

Better view of that red horse (Is he chestnut or something else? Not sure!) and his tobiano

It's notated in genetic testing as to (off) and TO (on).  Some people say that if there are dark spots in the white, that means the horse is homozygous tobiano (homozygous = both genes turned on), but that may or may not be true.

This is going to be a theme with the white patterns: they can hide. There's a theory - or at least there was - that there are either white enhancers or white suppressors (or both) that determine how much white a horse expresses when it has basically any pattern but the Appaloosa ones (which have their own rules on how they express white).  That means that how a given gene can show can vary wildly from horse to horse.

Tobiano can range from high white socks (usually with even, smooth edges) and a white tail, all the way up to just the head being dark and everything else white.  You can get dark horses who just have a single white spot that crosses their spine.  Googling "tobiano horse" shows a lot of cool examples, although quite a few of them are mixed with other patterns!

Minimal expression of tobiano at the local show

Frame is the nasty one, in my opinion.  Remember, it's got that alternative name of lethal white overo, and it has it for a reason.

Frame is a dominant gene, usually notated as o (off) and O (on), but the chance that you'll ever meet one with both copies turned on is very, very low.  All of these color and pattern genes are mutations of genes the horse as a species already had.  Most of them are pretty benign mutations - they don't really affect anything negatively.

Frame is different.  Frame actually affects the development of the colon when you've got two copies of the gene turned on.  And by 'affects' - it stops it. Foals who are OO are carried to term normally and are born white or near-white.  They typically have blue eyes.  And within a few hours of birth, they start to colic, because their intestines don't actually work, and they have to be put down.

And frame hides pretty effectively sometimes.

In its largest expression, you get a horse where - well, think of it like you're looking at a drawing of a horse.  All the edges are colored in, and the middle is white.

You know, kind of like this. (From a local show)

Or this guy.  (From a local show)

The pattern is generally termed horizontal - it goes along the length of the body, not up and down - and it only ever crosses the mid-line of the body if another pattern is involved.  The edges are jagged and uneven.  Tails stay dark, but the face may have bold white.  Frame can also cause blue eyes.

In lesser expressions, though... it puts points on socks, and that might be all you can see - or it might even just turn the horse's eyes blue, if the horse doesn't have white.  It likes to make other patterns jagged and sharp around the edges, and if the other pattern is big enough - like, say, a large tobiano pattern - those sharp edges might just be all you see of it.

What this comes down to is: test your horse if you're going to breed, if there's any chance mare and stallion might have pintos in their pedigrees and you don't know for a fact that their parents don't have frame.  Don't be the backyard breeder that doesn't test and then goes on FB or forums begging for sympathy for your sick foal.  Don't be the breeder that gets a white foal and puts it down because you assumed it's a double-frame because it's white; double creams can look white and other patterns can produce white foals with perfectly healthy intestines.  Just... don't.  The test is like $25 in the US plus postage to mail in some hair; if you're breeding horses with pinto patterns, you have no excuse.

*cough*  Sorry, had an opinion caught in my throat there.  Let's move on.

Splash (or splashed white) is kind of fun.  There are actually four documented versions of splash - SW1, SW2, SW3, SW4, and a theoretical SW5 (or more).  And off is just sw.  Like cream, it seems to be incompletely dominant; one copy turned on gives you white, and two copies turned on gives you more white.

Two copies gets complex, though, when you've got this many possible types.  Homozygous SW1 (two copies turned on) is fine, and not uncommon.  So far, they haven't found horses with two copies of SW2, SW3, or SW4, so the theory is that those foals may just be aborted in utero.  However, there are horses with test results showing two different versions of splash - say, SW1SW2 - and those are obviously walking around just fine.  (No SW2SW3 documented so far, though.)

As a general concept, highly expressed splash white looks like what would happen if you picked up a model horse and dipped it toes-first into a bucket of white paint.  The topline stays dark, but the face, body, and legs are white, and the tail may be too.  Lesser expressions aren't quite so dramatic.  High white socks/stockings and white belly spots are common.  So are bottom-heavy blazes - where the white on the nose is wider than the white on the forehead - and bald faces.  The edges of the pattern are crisp and even, and blue eyes (or partial blue eyes) are common.

Possible splash - look at that white face!

One side note - if the white reaches the ears, which can happen, there's a chance that the horse will be partially or completely deaf.  It's not true for all horses where the white reaches the ears, because it apparently depends on whether the white reaches the inner ear, but it does happen.

Splashed white 1 is far and away the most common of the four.  It's been found in everything from stock horses to Icelandics to Shetlands, and it's theorized to date back to before the development of most modern breeds.

Borrowing from Wikipedia again - pretty high white expression here.

Splashed white 2 traces from a single QH mare foaled in 1987, apparently, and there are rumors that it's related to the Gunner line of Paints as well.  It looks pretty similar to SW1.

Splashed white 3 is similarly a look-alike for SW1 and thought to be related to a small group of horses; at the time the paper that identified it came out, there were only two examples known.

Splashed white 4 is even more rare!  It showed up in a single (and sterile) Franches-Montagne horse and is sometimes called macchiato.  Equine Tapestry has a great post about him here.

Splashed white 5 and up are mostly theoretical at this point, as far as I can tell - they're believed to exist, but there don't seem to be tests or completed studies yet.  There's some talk about an "Appaloosa splash," but the paper it points to doesn't seem to talk about that at all (as best as I can tell).  There's also a family of Australian stock horses - the Bald Eagle line - that look splash, but thus far haven't actually tested as splash.  (You can see those guys here.)  There are also splash-like (and sabino-like, which we'll talk about in the next post) patterns in Gypsys and Clydesdales that haven't been identified genetically yet.

The Splashed White Project page at Equine Tapestry is actually an awesome place to see some of the variants of splash - she's got them grouped by gene combinations, so you can look at all SW1SW1 horses, or all SW1 horses with frame.

Some combinations can be pretty flashy!  It's not always easy to tell when you're seeing a combination of patterns, but often the major patterns are easy to spot - up and down shapes from tobiano, jagged white from frame, white faces from splash.

At least tobiano and splash on this guy (at a local show)

Tobiano and frame or sabino (see the ragged edges?), same local show

Other side of the same horse

Tobiano, frame, and maybe splash (looking at his face) at the same local show

Either splash (see the belly spot?) and frame, judging by that neck white and the points on the leg white - or sabino, which we'll talk about next. (At the local show)

Now, let's go back to our theoretical horse from yesterday.  Let's say he has splash.  Now his test results would look something like this:

Ee aa CrC zz DD chch toto oo SW1sw lplp

He gets the toto because he doesn't have tobiano, the oo because he doesn't have frame, and the SW1sw because he's got one copy of splashed white 1.

Next post, I'll talk about the roaning patterns: roan, rabicano, and sabino.