Agouti restricts black pigment to the points. A is dominant agouti and restricts black colouring into the typical bay configuration of black on the ears, muzzle, legs up to/below the knees and hocks, and mane & tail. Homozygous red (e/e) base horses are not visibly modified by agouti.

At (sometimes written as A^t) is a semi-dominant variant of agouti that causes seal brown instead of bay on black based horses. Seal Brown also restricts black pigment to the points like bay, however these horses will have an overall darker body shade without the typical reddish tint of a true bay, and all of the "soft areas" such as the muzzle, around the eyes, and through the flanks will be tan. Keep in mind that not all breed registries recognize seal brown as a separate colour, nor do all languages have different terms of A and At.

a, also written A^a, is the absence of an agouti modifier. If both pairs are homozygous recessive (a/a) then no agouti modifier is visible on a black based coat and the horse remains black in the absence of other modifiers.

E/* A/* = Bay
E/* At/At or At/n = Seal Brown
E/* aa = Black
ee + agouti = no modification, chestnut

A recessive flaxen modifier has been identified for red manes & tails and, when in use, uses the allele markers F/f. Both black and red horses can carry flaxen without expressing it, and only red horses that are homozygous for the recessive flaxen modifier will have the diluted mane & tail. Note that particularly dark bodied chestnuts with strikingly pale or golden flaxen mane & tail are sometimes called liver chestnut.

Anything + F/* = no change
Black bases + F/* or f/f = no change
Red bases + f/f = flaxen expressed

Dun is a complete dominant dilution with a few known non-diluting recessives on the same allele pair. This randomizer is only concerned with D Dun and d absent, but non-dun horses can be tested for and proven to carry non-dun 1 (nd1) and non-dun 2 (nd2) which cause primitive dun markings on undiluted horses. This includes doral stripes and lower limb zebra striping.

D dun dilution dilutes both red and black pigment throughout the body while leaving the mane, tail, dorsal stripe, and (usually) zebra striping on the legs lower legs.

E/* A/* D/* = Classic Dun, also known as bay dun, zebra dun, or simply "dun." Lighter shades can be mistaken for buckskin with primitive markings. At/* duns look very similar and are usually not classified differently. Note that Norwegian Fjord horses are typically the At form of dun, and this is called brunnblakk which means "brown dun."
E/* a/a D/* = Blue dun, also called grullo, grulla, or mouse dun. Norwegian Fjord horses call this grå, which literally means "grey."
e/e D/* = Red dun, also called claybank dun. Norwegian Fjord horses call this rødblakk, which means "red dun."

Dun + Palomino = Dunalino or Palomino Dun. Norwegian Fjord horses call this gulblakk, which means "yellow dun."
Dun + Buckskin = Dunskin or Buckskin Dun. Norwehian Fjord horses call this ulsblakk, which means "white dun."
Dun + Smoky Black looks like blue dun and doesn't have a special name. Some people may choose to use a unique term like Smoky Grullo. Norwegian Fjord horses do not distinguish these from grå.
Dun + Double Cream = the double cream colour. Dun markings are not obvious. Norwegian Fjord hroses call this kvit, which means "white," and disqualify these horses from the stud book.

Note that cream and pearl are found on the same allele pair, so it impossible for a horse to be homozygous for both cream and pearl. Not all breeds that recognize cream recognize (or truly carry) pearl, but most breeds that recognize pearl also recognize the traditional creams.

Cr cream is an incomplete dominant dilution, which means heterozygous and homozygous cream dilutions look different. Pearl is a similar dilution and will create a pseudo homozygous cream look when combined with Cr.

Prl pearl, also called Barlink Factor and formerly called Apricot, is a recessive dilution. If paired with cream (Cr/prl) it further dilutes the single cream dilution into something very similar to a true homozygous (double dilute) cream. In its homozygous form (prl/prl) Pearl dilutes reds to an apricot shade and does not touch black.

Cr/n = Single cream dilution. Chestnut + Cr/n = Palomino, Black + Cr/n = Smoky Black, Bay + Cr/n = Buckskin
Cr/Cr = Double cream dilution. Chestnut + Cr/Cr = Cremello, Black + Cr/Cr = Smoky Cream, Bay or Seal Brown + Cr/Cr = Perlino
Cr/prl = Pseudo double cream. These will appear the same as the true doubles above, but may have a mane & tail colour closer to the body colour.
prl/prl = Pearl dilution on red only, body lightens to a uniform apricot colour. E/* a/a prl/prl = no change. e/e prl/prl = Pearl (Apricot). e/e A*/* prl/prl = Pearl Bay (Apricot Bay).
prl/n, n/n = no dilution

Champagne is a dominant dilution that modifies both red and black coats. Champagne horses are known for hazel eyes and pink, freckled skin. Red hairs become golden yellow and black hairs become a chocolate brown.

Black + Ch/* = Classic Champagne, which dilutes body and mane & tail to a chocolate brown. This is occasionally mistaken for a dilution on grullo and may be misclassified as "Lilac Dun."
Seal Brown + Ch/* = Sable Champagne, which is visually very similar to classic champagne.
Bay + Ch/* = Amber Champagne, which dilutes the red body to a gold while diluting the mane, tail, and points to chocolate brown.
Chestnut + Ch/* = Gold Champagne, which dilutes the body to a gold colour and the mane & tail to ivory. At a glance, this may look like palomino, but there will be mottling around the nose and the horse is likely to have hazel eyes.

Palomino + Ch/* = Gold Cream, also called Ivory Cream. These horses look like cremellos, but with the tell-tale muzzle mottling, eye skin freckling, and likely hazel eyes of champage.
Buckskin + Ch/* = Amber Cream. Visually similar to perlino, but with a darker mane, tail & points (not always) that can be anywhere from slightly darker than the body to a rich chocolate brown.
Seal Brown + Ch/* = Sable Cream, which resembles amber or classic cream, but with a cooler undertone.
Smoky Black + Ch/* = Classic Cream, which resembles a particularly pale classic champagne.

Double Cream (and Psuedo Double Cream) + Ch/* = Indistinguishable from double creams without freckles. Eyes are a light blue.
Smoky Cream + Ch/* = Classic Smoky Cream or Smoky Cream Champagne (or simply called Smoky Cream)
Perlino + Ch/* = Amber Perlino or Perlino Champagne (or simply called Perlino)
Cremello + Ch/* = Gold Cremello or Cremello Champagne (or simply called Cremello)

Silver is a dominant dilution of black hairs only. This is often called "silver dapple" in the western hemisphere and "taffy" in Australia and New Zealand. Black mane & tail hairs are diluted to a silvery grey or flaxen colour and the body is diluted to chocolate brown, with or without dappling that may be as light as the mane & tail. The points are always silver.

Black + Z/* = Black Silver, Silver Dapple, or Taffy. These horses have a chocolate body, with or without dappling, and silver or flaxen mane & tail.
Bay/Seal Brown + Z/* = Bay Silver. These horses has a redder body and tend toward more flaxen shade in the mane & tail.

Silver should not be confused with the greying process of dominant Grey, particularly when Grey produces dapples. Other colours that are often mistaken for silver are flaxen/liver chestnut and sooty palomino.

Grey is a complete dominant and causes a progressive loss of pigment in all hairs. White hairs can be present at birth or will begin to appear shortly thereafter. Greying is a complex process that does not progress at the same rate, or produce the same changes and patterns, on every grey horse. Some will dapple while others will mimic roan in the early stages of greying. All grey horses will eventually become mostly "white," though heterozygous greys in particular may retain small spots of colour called "flea bites." Grey horses that have progressed to white have undiluted skin and eyes, unlike horses that appear white due to dilutions or extremes in certain white/spotting patterns.

G/* = Grey, g/g = not grey.

Roan is a dominant modifier that disperses white hairs into the body while leaving the head, lower limbs, mane & tail untouched. Roan is known to be lethal in homozygous form, so this randomizer only accepts inputs of rn/rn (not roan) and Rn/rn (heterozygous roan.) If you attempt to breed two roans together it will get sassy with you (no matter what) and may return a dead foal instead of a genotype report.

"Corn spots" refers to flecks of solid colour within the roaned body, often appearing after the skin is damaged. Bay roans typically also have a distinct "inverted-V" shape to the edges of their black lower leg markings when viewed from the front.

Blue Roan = Roaning on a black or seal brown horse, dispersing white hairs into a black or near-black body. This is frequently confused with grullo.
Bay Roan = Roaning on a bay or particularly light seal brown horse, dispersing white hairs into a red/brown body. This used to be called "red roan" in some registries. Red Roan = Roaning on a chestnut horse, dispersing white hairs into a red body. This may also be called chestnut roan or strawberry roan

Roans can sometimes have "reverse dappling" (rings of paler colour) and will have a constantly changing coat. Roan tend to look vastly different in their winter and summer coats.

Sabino category white patterns and rabicano can mimic roaning in breeds that do not carry roan, and are usually responsible for any "roan" Arabians you come across. Varnish Roan is a progressive marbling present in some horses with leopard complex spotting and is not the result of true roan.

Tobiano is a dominant gene that produces loud white patterns on horses of many breeds. It's one of the two main genes that come to mind when thinking of a "pinto" horse and associated with the American Paint Horse breed. Tobiano horses without mixed patterns from other white pattern genes will typically have a solid coloured head with or without typical solid horse white facial markings (star, snip, stripe, etc.) with the dark colour of the face extending part or all of the way down the sides of the neck. The arrangement of white patches (on pink skin) is vertical and typically does cross the topline (over the spine) somewhere between the whithers and tail. A tobiano horse's legs are typically all white from the knees down at least, if not higher up.

to/to = no pattern
TO/* = Tobiano pattern present

The term "tovero" generally refers to a mixing of tobiano and frame overo patterns on the same horse, though some breeds use it as a term for tobiano plus any other non-leopard white pattern.

"Piebald" is a UK term for a black & white horse with Tobiano or any other white pattern. "Skewbald" is the equivalent UK term for colours other than black. Bays with white patterns are sometimes alternatively called "tricolour."

"Overo" as a general term can refer to many different non-Tobiano white patterns across many breed registries. "Frame" or "Frame Overo" is the actual genetic pattern. Similar to Roan, Frame is lethal in homozygous form (Overo Lethal White Syndrome) and this randomizer will get sassy if you breed two Frame Overo horses together.

Frame white spots are sharp and expressive shapes with jagged edges and are arrange horizontally across the body. Frame horses have a solid topline (white does not cross the spine between the withers and tail.) They usually have coloured legs and a solid, one-colour tail. The face is usually more white than colour, and blue eyes are common.

Frame is a complete dominant, which means if a foal is born with frame spotting then at least one of the parents also have frame spotting. Whenever you come across cases of two "solid" parents parents producing a frame foal, at least one of the "solid" parents is actually a minimally expressed frame overo or the white spotting is completely covered by extensive greying, maximum expressions of dominant white or leopard, or a double dilution.

Fr/fr = frame over spotting present.
fr/fr = solid (or other pattern)

"Tovero" refers to a mixing of Tobiano with any of the patterns frequently called "overo," including both frame overos and other types of overos.

"Splash Overo" is an outdated term for overo-type spotting caused by one of the Splash White genes, which are found on a different locus.

"Sabino" patterns are sometimes also called overo by certain groups and breed registries. Sabino1 can be genetically tested for, but be aware that there are other types of sabino suspected that have no yet been genetically identified.

Sabino is a group of white patterns known for belly spots, roaning on the edges of white spots, white chins, and irregular facial white. Blue eyes are also common with sabino horses. When sabino combines with other white patterns it exaggerates the pattern and increases the amount of white present on the horse. Horses referred to as "Sabino White" or "Maximum Sabino" are homozygous for SB1 or have a combination of sabino and at least one other pattern (testable or otherwise) that have resulted in a mostly white horse that is not grey or a double dilute.

Sabino 1 is the testable gene responsible for sabino patterning. It was named 1 when it was discovered in 2005 because researchers expected to later identify sabino 2, sabino 3, etc. but no such alleles have been found to date. (This section last updated in 2021.) It is now thought that Sabino 1 is actually a Dominant White allele and should have been named accordingly. Sabino 1 is present in Miniature horses, American Quarter Horses, American Paint Horses, Tennessee Walkers, Missouri Fox Trotters, Mustangs, Shetland Ponies, and Aztecas. It is NOT present in Arabians, Thoroughbreds, Standardbreds, Shires or Clydesdales, so "sabino" spotting in these breeds is due to a currently non-testable gene.

n/n = no sabino spotting
SB1/n = sabino spotting
SB1/SB1 = sabino spotting, likely in maxmimum expression (mostly white)

Patterns commonly attributed to "sabino" but are not caused by SB1 are: frame overo (Fr/fr) splash white (4 alleles identified) roan (Rn/n) rabicano, grey (G/g) various forms of dominant white, and yet unidentified "sabino-type" patterns. The sabino spotting in Arabians and Thoroughbreds are likely dominant white variants.

Rabicano is thought to be a dominant gene and may be caused by an allele similar to SB1. Rabicano is famously present in Arabians and is characterized by roan-like white hairs present on the belly/flanks and at the base of the tail, often with white present in the tail itself causing a "skunk tail" appearance. Horses claimed to be "brindle" with white hairs are usually rabicano. True roan and varnish roan can mimic rabicano.

Splashed White is a family of "overo" (non-Frame Overo) white spotting patterns that range from minimal lower limb white to a "dipped in white paint" look. Blue eyes are usually found in Splash horses and some expressions of Splash are associated with deafness.

Splash White 1 (SW1) 3 (SW3) 5 (SW5) and 6 (SW6) are located on the MITF locus along with macchiato, and Splash White 2 (SW2) and 4 (SW4) are found on PAX3. This means horses can have up to 2 different splash patterns, but only certain combinations are possible.

n/n = no pattern
SW#/n = minimal splash pattern. A single copy of any one splash white gene will produce white on up to 50% of the body, starting with the lower limbs, belly, and chin, and may have such little white that they appear to be a solid horse with socks. Blue eyes are common. Note that SW2/n is usually mistaken for a solid horse with white lower leg markings. SW4/n is known to cause very white facial white markings.
SW#/SW# = classic splashed white with a loud "dipped in white paint" look and blue eyes. May be more than 50% white. This can be homozygous of a single SW allele that is not thought to be lethal in homozygous form (homozygous SW1 is common and a single live adult homozugous for SW2 has been indentified.)
At this time it is believed that all other SW alleles are lethal in homozygous form, so SW3/SW3, SW4/SW4, SW5/SW5, and SW6/SW6 are not parent seleciton options in this randomizer and you do have a chance of getting a dead foal result if you breed matching carriers of these forms together.

"Macchiato" is a Splash variant on MITF identified in a Franche-Montagne stallion. It is thought to be a spontaneous mutation that will not be passed on and it is not identified in any other breed.

SW1 is found in the American Quarter Horse, American Paint Horse, Icelandic horse, Miniature horse, Morgan horse, Shetland pony and Trakehner.
SW2 is mainly found in the American Quarter Horse and American Paint Horse
SW3 is exclusive to the American Quarter Horse and American Paint Horse and is rare.
SW4 is rare and found in appaloosa horses (which combines with the leopard complex to form a pintaloosa pattern.)
SW5 is known to cause deafness in most carriers and is found in some lines of American Paint Horses.
SW6 is similar to SW5 and has been indentified in a single line of American Paint Horses.

The "Leopard Complex" set of genes are responsible for "appaloosa" spotting and patterns are determined by the combination of the Leopard (LP/lp) and pattern genes.

A pattern gene is required to produce the blankets of white that reveal leopard spotting from birth and produce the typical spotted patterns associated with appaloosa horses. PATN1 is the only testable leopard complex pattern to date and is thought to be a complete dominant (heterozygous and homozygous do the same thing) but other non-testable pattern genes may exist.

Leopard is an incomplete dominant gene that causes Dalmatian-like spotting and faux-roan progressive roaning when present. The Dalmatian-like spots are present at birth and may be visible as darker dappling on solid areas of fur, but require a PATN blanket of white to be visible at birth. Horses with leopard that do not have a pattern gene will likely appear solid at birth, but may roan out ("varnish roan") as they age, and this may reveal their leopard spotting. Leopard horses with a pattern can also "roan" with age.

Note that the "roaning" found in leopard horses is called "varnished roan" and is not cause by true Roan (Rn/rn)

lplp = No spotting.
Lp/* + no pattern = No spotting at birth but may "roan" with age, which can reveal spotting.
LP/lp + PATN1/* = Leopard spotting on a limited blanket. This can be anywhere from a varnished roan with a sprinkling of white to a classic blanket appaloosa pattern to partial or full leopard (Dalmatian look.)
LP/LP + PATN1/* = Leopard spotting on a maximum blanket. This can be anywhere from a snowcap blanket (entire topline from withers to tail is white, extending any distance down the sides of the body) to a very clean full leopard appaloosa (no errant colour left on the knees and hocks) to "few spot" which is a pseudo-white with a few remaining spots of colour.

You can tell that your varnished roan or few spot appaloosa is indeed an appaloosa and not a true roan or maximum white pinto patterned horse by looking for tell-tale leopard traits. Leopard causes mottling of the skin, particularly on the soft bits of the muzzle, eyes, and genitalia. Leopard horses are also known to have stripes on the hooves and white sclera. Note that a varnished roan will have white hairs in areas that normally stay solid on a true roan, such as on the sides of the face and on the lower limbs, and the spotting left on a fewspot appaloosa will differ from the spots of colour left on a maximum white pinto or a fleabitten grey in that the remaining spots of colour will still be uniform, clean-edged spots like on a Dalmatian dog. A varnished roan that reveals leopard spotting will differ from a true roan with corn spots in the same way; the spots are larger than typical corn spots and have clean edges.

"Pintaloosa" refers to any horse with a mix of a pinto white pattern and visible leopard spotting.

Dominant White is a family of mutations on the KIT gene (which is also where Tobiano, Sabino 1, and true Roan occurs) and all are dominant expressions of the gene, though not all of them are complete dominants. Please be aware that while some W alleles are thought to be homozygous lethal resulting in auto-abortion (miscarriage) some are known to be incomplete dominants and have been found in homozygous form in live adult horses. Since this randomizer is taking a simplified approach to Dominant White due to the insane number of variants, it will not get sassy with you about homozygous forms of the alleles thought to be homozygous lethal. It will, however, error if you report that one or both parents was submitted with more than 2 KIT pattern alleles.

All Dominant White patterns began as a spontaneous KIT mutation in a single individual, but many have been passed on and inherited through families, to the point where we actually have breeds that are known for their White alleles. The Camarillo White Horse gets its namesake colour from W4. Remember, once again, that Sabino 1 is actually also a Dominant White gene and cannot be homozygous along with another W, or heterozygous in the presence of two W alleles, as these all occur at the same locus.

Dominant White causes depigmentation of the skin and hairs in the affected part of a horse's body, which means the skin is pink (unlike end-process grey horses that appear white) and the hairs have absolutely no pigment left (unlike the creamy tones left in double dilutions.) Dominant White is not known to affect eye colour and usually leaves the eyes brown.

W1 is exclusive to the Franches Montagnes breed, from the 1957 mare Cigale, and usually results in entirely or mostly white horses with some residual colour left on the topline.
W2 comes from the 1946 Thoroughbred stallion KY Colonel and is known to cause near or completely white horses, though they may be born with more colour and go through a gradual depigmentation process with age.
W3 comes from the 1996 Arabian stallion R Khasper and produces mostly-white coats. Some W3 horses also have blue eyes, but it is thought that they inherit that trait from a different gene. W3 is thought to be homozygous lethal so W3 carries should not be interbred. W3 is likely responsible for "maximum sabino" expressions in Arabians.
W4 is the gene behind the Camarillo White Horse breed originating with the 1912 stallion Sultan, and is not homozygous lethal. Like W1 and W3, these horses are completely white or born mostly white with topline colour that fades with age.
W5 comes from the 1984 Thoroughbred stallions Puchilingui and produces anything from a loud but typical "sabino" white pattern to nearly completely white horses. W5 is likely responsible for many "maximum sabino" expressions in Thoroughbreds.
W6 occurred spontaneously in a 2004 Thoroughbred mare named Marumatsu Live and has not yet been passed on. The full range of inherited expression is not known, but Marumatsu Live is nearly all white.
W7 occurred spontaneously in a 2005 Thoroughbred stallion named Turf Club and has not yet been passed on. The full range of inherited expression is not known, but Turf Club is nearly all white.
W8 occurred spontaneously in the Icelandic Horse stallion Pokkadis vom Rosenhof, who has roan-like spotting, and has not yet been passed on.
W9 was found in a single Holsteiner horse that is nearly all white, and has not yet been passed on.
W10 occurs in American Quarter Horses and has a wide range of expression from loud leg & face white to sabino-like spotting, to nearly all white.
W11 has been found in a family line of South German Draft horses, suspected to have started with an all-white 1997 stallion named Schimmel.
W12 occurred spontaneously in a 2010 Thoroughbred colt that died the same year. He was half white.
W13 was first identified in a family of Quarter Horse x Paso Peruviano crossbreds and causes all-white bodies. It was originally thought to have come from the Quarter Horse ancestry, but has since been identified in an American White Horse with no recorded Quarter Horse ancestry, so the exact origin is unclear.
W14 is found in Thoroughbred and is suspected to have originated with the 1996 stallion Shirayukihime. These horse are fully or mostly white but may have a few spots of remaining colour.
W15 comes from the 1996 Arabian stallion Khartoon Khlassic and has been proven to be an incomplete dominant. Heterozygous W15 horses have a sabino-like pinto pattern and homozygous W15 horses (or those with W15 and another W allele) tend to be all white.
W16 originated in Oldenburger horses, possibly starting with the 2003 mare Celene. W16 horses are either heavily roaned or all white.
W17 was found in a single Japanese Draft horse that was all white with one blue eye.
W18 comes from the Swiss Warmblood mare Colorina von Hoff and produces extensive white speckling.
W19 originated in three part-Arabians related to the 1990 mare Fantasia Vu, and produced a combination of white markings similar to splashed white.
W20 is found in many breeds and only causes small white markings on its own. W20 creates socks and blazes with the possibility of very small white spots elsewhere on the body, adding a little chrome to what is otherwise considered a solid coloured horse. When combined with another W allele, SB1, or Tobiano, however, W20 exaggerates the other pattern to create mostly white horses. (Up to date as of July 2021: W20 has been identified in the German Riding Pony, German Warmblood, Thoroughbred, Oldenburger, Welsh pony, Quarter horse, Paint horse, Appaloosa, Noriker, Old-Tori, Gypsy Vanner/Irish Cob, Morgan, Clydesdale, Franches-Montagnes, Marwari, South German Draft, Peruvian Paso, Camarillo White Horse, and Hanoverian)
W21 is found in Icelandics originating with the stallion Ellert frá Baldurshaga, causing a white face with speckles and odd patches across the body. This colour is called "ýruskjóttur."
W22 originated in the 1989 Thoroughbred mare Not Quite White and produces sabino-like patterns on its own or completely white horses when combined with W20.
W23 originated in the white Arabian stallion Boomori Simply Stunning who did produce two white foals, but it does not to appear to have been passed on beyond this.
W24 comes from the 2014 Trottatore Italiano stallion Via Lattea and produces a mostly/all white horse.
W25 started in the Australian-born Thoroughbred mare Laughyoumay, who was all white, and has been passed on to white and mostly-white foals, some with remaining colour on and around the ears.
W26 started in the Australian-born Thorougbred mare Marbrowell, who has a vertically arrange spotting-and-roaning pattern similar to sabino. When combined with frame overo, this W allele causes a completely white foal.
W27 originated in the Australian-born Thoroughbred mare Milady Fair and is mostly present today through horses related to her grand-colt Colorful Gambler. W27 produces a sabino-like white pattern and is becoming more and more prevalent in Thoroughbred/related show jumpers and American Paint Horses.
W28 is a sabino-like mutation identified in a German Riding Pony foal in 2019.
W29 no information found
W30 is found in Berber horses and produces mostly/all white coats.
W31 comes from the American Quarter Horse stallion Cookin Merada and produces a mostly/all white horse.
W32 is found in American Paint Horses and causes high white on the legs, bold facial markings, and occasional small body spots similar to W20.

Arabian purebred and related horses can carry W3, W15, W19, and W23.
Thoroughbred purebred and related horses can carry W2, W5, W6, W7, W14, W20, W22, W25, W26, and W27.
Quarter Horse purebred and related horses can carry W10, W13, W20, and W31
Paint Horse purebred and related horses can carry W20, W27, and W32
Camarillo White Horse horses always have W4 and can also carry W20
Icelandic purebred and related horses can carry W8 and W21
Holsteiner purebred and related horses can carry W9
Oldenburg purebred and related horses can carry W16 and W20
Swiss Warmblood purebred and related horses can carry W18
German Riding Pony purebred and related horses can carry W20 and W28
Franches Montagnes purebred and related horses can carry W1 and W20
Trottatore Italiano purebred and related horses can carry W24
Berber purebred and related horses can carry W30
Hanoverian and other German Warmblood Stud Books have been found to carry W20
South German Draft purebred and related horses can carry W11 and W20
Welsh, Noriker, Old-Tori, Gypsy/Irish Cob, Morgan, Clydesdale, Marwari, and Peruvian Paso can carry W20

Bend-Or spots, also known as grease spots, are spots that are darker than the rest of a non-white coat, not associated with dappling or the greying process, and not thought to be scarring. A gene for this trait has not been identified yet but may be related to sooty.

Brindle in horses in one of three things: mistaken other pattern, chimerism or a KIT mutation. Roan, varnish roan, grey, sabino 1 and sabino-type patterns including rabicano, and certain dominant white alleles can create verticle speckled banding that looks like brindle. "Reverse brindle" where the bands are white are almost certainly a mistaken other pattern. "True brindle" where the banding is darker is the result of chimerism (sporadic expression of an absorbed twin's genetics) or a spontaneous KIT mutation not otherwise identified.

Liver Chestnut refers to a dark, chocolate shade chestnut (red) horse with matching or paler mane & tail, frequently flaxen. It is thought that sooty may be responsible for darkening the body colour of these chestnuts.

Pangaré, also called mealy, created paler flaxen or grey hairs (but notably not silver hairs) on the muzzle, around the eyes, and ink the flanks. It will sometimes extend across the belly and appear on the lowest parts of the legs as well. Many foals are born looking like this and shed it out as they grow. Some breeds are known to keep this colouring, such as the Norwegian Fjord Horse, Exmoor Pony, American Belgian Draft, and Haflinger. "Belgian sorrel" is a term for chestnuts with pangare.

Primitive markings including dorsal stripes, shoulder stripes, and zebra striping on the legs are associated with dun and can appear in horses that aren't diluted by dominant Dun but carry one of two other non-dun recessive alleles on that gene.

Sooty is the dispersal of black or darker hairs into a non-black coat starting at the topline and extending down. No single gene has been found to be responsible for sooty in horses, and similar colour modifiers in other species such as rats have been found to be caused by interactions of multiple genes.

Mushroom is a dilution found exclusively in families of Shetland ponies in the UK and is known to dilute red pigment. Chestnut coats to a much paler grey or pink-tinted shade. Adults may or may not darken back to a truer chestnut. The non-black parts of bay coats lighten to a yellowish beige with countershading along the topline and tend to resemble buckskins as adults. This is a complete dominant, so it only needs to be inherited from one parent, and a black parent carrying mushroom will not show it. Due to the extreme rarity of this gene it has not been included in this randomizer. Feel free to substitute another gene if you want to include it in your randomization.

Tiger eye, also called goat eye, is a dilution of the eye pigment without any visible effect on coat colour. This is only found in the Paso Fino horse, and all other ocular dilution in other breeds is caused by other genetics. There are two incomplete dominant tiger eye alleles, TE1 and TE2, and one recessive "normal" allel n. In order for a horse to have diluted eyes due to this gene it must not have a 'n' allele. TE1/TE1 and TE1/TE2 produces yellow, amber, or bright orange eyes. TE2/TE2 produces in cream diluted horses and no change on other horses.

Isabelline, also known as isabella, is not a specific colour but refers to any diltuion that results in a very pale coat colour with a yellow or cream hue to it and correspondingly pale mane & tail, such as cremello.

Sorrel is an alternate word for chestnut, which is recessive e/e extension without modifers and dilutions.

Crop-out, when referring to abnormal white markings and patterns, is an outdated term from breed registries that do not accept excessive white. A foal would be called a crop-out when two seemingly solid horses produced a foal with excessive white, and the foal was considered inelligble for registration. These days these cases are understood to be louder expressions or combined effect expressions of white patterns carried but minimally expressed by the parents.