Hoofprint Valley · Reference

Horse coat genetics

Real inheritance, breed-specific colours and white markings. Breed labels describe populations; DNA variants explain the coat.

How colour is inherited

A foal receives one allele at each locus from each parent. Dominant variants can express with one copy; recessive variants generally need two. A hidden allele can still pass to a foal.

Extension (MC1R) and Agouti (ASIP): ee makes chestnut/sorrel. E_ permits black pigment; A_ limits black to bay points, while aa allows black all over. Agouti cannot make black points on ee. Dark bay/brown shades are not a separate proven allele in this game.
Cream and pearl (SLC45A2): One cream makes palomino on chestnut, buckskin on bay and smoky black on black. Two creams give cremello, perlino or smoky cream, with pink skin and pale blue eyes. Pearl needs two pearl alleles, or cream/pearl for a strong dilution. Cream and pearl occupy the same two allele slots, not independent loci.
Dun (TBX3), silver (PMEL), champagne (SLC36A1): Dun dilutes body pigment and retains primitive markings. Non-dun variants can also produce a dorsal stripe. Silver affects black pigment and is hidden on chestnut. Champagne dilutes pigment and produces freckled pink skin and lighter eyes.
Grey (STX17) and classic roan: Grey horses are born coloured and progressively whiten at variable rates, usually retaining dark skin. Classic roan mixes white body hairs while the head and lower legs stay darker. LP varnish, sabino ticking and grey are not the same mechanism as classic roan.
White spotting: Tobiano, SB1, W variants, frame and splash have different causes and can combine. W20 is a variable white-spotting modifier, not a splash mutation. Overo is an appearance umbrella. White hair masks the underlying colour; the horse still passes its hidden base genes on.

Three inheritance examples

Ee × Ee: 25% EE, 50% Ee, 25% ee; only the ee group is necessarily chestnut-based.
Cr/N × Cr/N: 25% N/N, 50% Cr/N, 25% Cr/Cr. E/A determines which colour each dilution produces.
Cr/prl × N/N: 50% Cr/N and 50% prl/N; no foal receives both variants from that one parent.

Frame O/n × O/n has a 25% O/O lethal-white risk. LP/LP is associated with congenital stationary night blindness. A coat-colour reference is not a substitute for veterinary genetic testing.

Thoroughbred

Thoroughbred mare — coat drawn from recorded alleles; drawn to its recorded height.

Colours: Bay, dark bay/brown, chestnut, black and grey. Rare cream Thoroughbred lines exist; rarity is not genetic impossibility.
Markings & patterns: Ordinary face and leg white and several family-specific KIT white variants. A sabino-looking Thoroughbred is not automatically SB1-positive.
Inheritance: E and A establish the base; G masks that birth colour progressively. White variants must be identified by their actual test, not by a broad white marking.
In this game & what remains uncertain: The game records W20, not the many other Thoroughbred white variants. Dark bay/brown is a shade range, not a separately proven brown allele here.

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Mustang

Mustang mare · Star, front coronets, hind coronets — coat drawn from recorded alleles; drawn to its recorded height.

Colours: Spanish-type Mustangs can carry bay, black, chestnut, cream, dun and roan. Colour diversity depends on the particular population and ancestry.
Markings & patterns: Pinto and leopard-complex patterns occur in some Mustang populations; they are not universal Spanish Mustang traits.
Inheritance: Dun requires D, cream requires Cr, and leopard characteristics require LP. PATN1 alone does not produce spots.
In this game & what remains uncertain: The in-game Mustang pool is a broad fictional Spanish-type population, not a genetic inventory of every preservation herd.

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Percheron

Percheron mare · Wide blaze, front pasterns, hind stockings — coat drawn from recorded alleles; drawn to its recorded height.

Colours: Black and grey predominate; bay, chestnut and roan are reported in some populations or registries. Registry acceptance varies.
Markings & patterns: Usually solid with limited face/leg white. Grey whitening is not a dominant-white pattern or true roan.
Inheritance: A grey Percheron still carries and passes on its underlying E/A base colour. Two non-grey parents cannot produce a G-positive foal through ordinary inheritance.
In this game & what remains uncertain: The game uses a black/grey-focused pool and does not treat every rare historical colour as a sampled gene.

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Shetland Pony

Shetland Pony mare · Snip, front socks, hind coronets — coat drawn from recorded alleles; drawn to its recorded height.

Colours: Black, bay, chestnut, grey, cream and silver occur. Silver changes black pigment, not chestnut pigment.
Markings & patterns: Tobiano and ordinary white markings occur. Leopard spotting is excluded by the UK Shetland breed standard; standards and molecular tests answer different questions.
Inheritance: An ee pony can silently carry silver. Cream and silver are distinct dilutions; a flaxen chestnut need not carry silver.
In this game & what remains uncertain: Flaxen inheritance is not a validated single recessive gene; the saved F pair is a game approximation, not a real DNA test.

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Stock Horse

Stock Horse mare · Star and snip, front pasterns, hind socks — coat drawn from recorded alleles; drawn to its recorded height.

Colours: Quarter Horse-type stock horses commonly show sorrel/chestnut, bay, black, roan, dun and cream; champagne and pearl occur in particular lines.
Markings & patterns: Face/leg white, splash, frame and other white variants depend on family. Pinto appearance alone does not determine breed or registry eligibility.
Inheritance: Sorrel and chestnut share ee. Buckskin is cream on bay; bay dun needs D and primitive markings. These are not interchangeable genes.
In this game & what remains uncertain: Stock Horse is the game's broad ranch-horse type, not a claim that every stock registry has the same allele frequencies.

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Appaloosa

Appaloosa mare · Star, front pasterns, hind stockings, leopard complex, pattern-1 — coat drawn from recorded alleles; drawn to its recorded height.

Colours: Appaloosas have ordinary base colours and dilutions beneath leopard-complex patterning. Grey and true roan are different from LP varnish roaning.
Markings & patterns: LP is associated with mottled skin, striped hooves, visible sclera and progressive varnish. White coverage ranges from minimal to blankets and leopard; LP/LP commonly has few or no dark spots.
Inheritance: PATN1 increases LP white coverage but has no spotting effect without LP. Two LP/lp parents produce 25% lp/lp, 50% LP/lp and 25% LP/LP at that locus.
In this game & what remains uncertain: LP/LP is associated with congenital stationary night blindness. Exact blanket size, snowflakes and coverage need other modifiers; the game uses simplified blanket/leopard classes, not a complete pattern prediction.

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Hanoverian

Hanoverian mare · Snip, front coronets, hind stockings, white spotting modifier w20 — coat drawn from recorded alleles; drawn to its recorded height.

Colours: Bay, chestnut, black and grey dominate the Hanoverian population. Breed approval rules are separate from colour inheritance.
Markings & patterns: Ordinary white markings and lineage-specific white variants; a ragged blaze alone does not diagnose SB1.
Inheritance: Red pigment masks Agouti and silver effects; grey changes visible colour with age, not the underlying allele pairs.
In this game & what remains uncertain: The game's conservative founder pool omits uncommon or unverified dilution/pattern lines. Omission is not a scientific claim that a gene can never exist.

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American Warmblood

American Warmblood mare · Blaze, front socks, hind stockings, tobiano — coat drawn from recorded alleles; drawn to its recorded height.

Colours: American Warmblood is a performance-based population with diverse ancestry; bay, chestnut, black, grey and dilutions depend on its lines.
Markings & patterns: Solid, pinto and other patterns can occur according to ancestry and registry requirements. There is no single closed-breed coat-frequency table.
Inheritance: The same E/A, cream, grey and pattern mechanisms apply; ancestry changes which variants are present, not how those variants work.
In this game & what remains uncertain: The in-game founder weights are a curated subset, not measured American Warmblood population frequencies; crossbreeding remains disabled in the game.

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Clydesdale

Clydesdale mare · Wide blaze, front socks, hind stockings, white spotting modifier w20 — coat drawn from recorded alleles; drawn to its recorded height.

Colours: Bay and brown are classic; black, chestnut and roan descriptions also occur. White feathering is white hair, not a cream dilution.
Markings & patterns: Broad facial white, high leg white and belly splashes often look sabino, but classic Clydesdale sabino appearance is not proof of the SB1 mutation.
Inheritance: White markings are heritable and can involve KIT variants and other modifiers. Do not infer SB1/SB1 or true Rn just from extensive ticking.
In this game & what remains uncertain: The game records W20 and inherited white tendency; it cannot yet resolve every Clydesdale white/roaning mechanism. Existing recorded genotypes are retained for review, not silently replaced.

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Paint

Paint mare · Wide blaze, front socks, hind socks, tobiano — coat drawn from recorded alleles; drawn to its recorded height.

Colours: Paint Horses combine stock-horse base colours with white patterns: black, bay, sorrel, cream, dun, roan, champagne and rare pearl lines.
Markings & patterns: Tobiano, frame, splash and sabino may combine. Overo is an appearance category, not one gene; solid-bred Paints can occur.
Inheritance: TO is dominant; heterozygous frame carriers pass O to about half their foals. O/O causes lethal white foal syndrome, so carrier-to-carrier matings are unsafe.
In this game & what remains uncertain: Pearl and cream are variants at the same SLC45A2 locus, not independent genes. The current saved pairs are legacy bookkeeping; impossible combined pairs need review, not invented chromosomes.

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Connemara

Connemara mare · Blaze, hind pasterns — coat drawn from recorded alleles; drawn to its recorded height.

Colours: Grey, bay, black, brown, chestnut and cream occur. The traditional Connemara colour called ‘dun’ is generally buckskin from cream, not proven D dilution.
Markings & patterns: Usually solid with face/leg white. Grey dapples are not roan; modest white is not evidence of SB1.
Inheritance: E_ A_ Cr/n produces buckskin without requiring D. Cr/Cr produces a double-cream coat; G can hide either dilution as the pony ages.
In this game & what remains uncertain: New in-game founders must not get true dun merely because the breed's colour list says ‘dun’. Existing saved D alleles remain visible and flagged for review.

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Sources & model limits

Veterinary genetics references describe tested variants; breed colour lists and registration rules are not proof of a particular DNA mutation. Rare lines are not represented by every founder pool.

Founder weights are fictional sampling choices. New foals transmit cream or pearl from the shared locus; incompatible older records require review. Flaxen, precise LP coverage, grey timing and independently sampled KIT-region variants are simplified. Other splash and dominant-white variants are not yet represented. Existing horses are never given replacement genes to make them fit a breed description.

Reviewed October 23, 2026. Illustrations show game phenotypes, not laboratory results.

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