Coats & markings

A horse’s coat comes from real horse colour genetics: a base colour, dilutions that lighten it, patterns like roan and grey, and white markings on the face and legs. Every gene comes in two copies, one from each parent, and a horse can carry a copy it doesn’t show and pass it to its foals.

#The coats

These are the main coats, each on a real horse the game generated. The cards are the same portraits you see in your stable. Rarer colours (cremello, grullo and the rest) are further down.

#Base colour: black, bay or chestnut

Two genes set the base. Extension decides whether the horse makes black pigment at all: E (black) beats e (red), so only an e/e horse is chestnut. On a horse with black pigment, Agouti decides where the black goes: A keeps it to the mane, tail and legs (bay), At lets it spread over most of the body (seal brown), and two copies of a leave the horse solid black. A third gene, Liver, darkens a chestnut to liver chestnut, but only with two copies.

#Dilutions and patterns

• Cream lightens the coat. One copy turns chestnut to palomino and bay to buckskin; on black it barely shows (smoky black). Two copies give the pale cream coats: cremello, perlino and smoky cream.
• Dun lightens the body and adds primitive markings: a dark stripe down the back and barring on the legs. Bay becomes bay dun, chestnut red dun, black grullo.
• Roan mixes white hairs through the body while the head and legs stay dark: strawberry, bay and blue roan.
• Grey is a pattern that comes with time; it has its own section below.

Rarer colours

Real horses from the game, each given exactly the genes in its caption.

Genes stack: a buckskin that is also dun is a dunskin; a palomino roan is a palomino with the roan gene. The game names the combination.

#Grey: born coloured, white by the end

Grey (G) needs only one copy. A grey foal is born in its base colour and starts greying out. From racing age the coat is dapple grey, and by 24 starts, or when it retires from racing, it is fully grey. It goes by career, not by the calendar. A grey also hides the dun stripe once the grey shows.

The horse page names the colour a grey was born as (this one: “Grey, born bay, greying with career”). Under the grey it still carries those base genes and passes them on.

#White markings

Face and leg white comes from many small genes adding up, plus the Sabino gene. Each horse has a white tendency: the higher it is, the more white. On the face that runs from a plain face through a star, snip, stripe and blaze to a bald face; on the legs from a coronet to a sock to a stocking. Hind legs carry a little more white than front legs.

One copy of Sabino-1 adds white face and leg markings; two copies give a loud white pattern with patches on the body. Markings are inherited like everything else, with a small chance each time that the white tendency drifts a little.

#Hidden copies and coat odds

Because black beats red and bay beats black, a horse can carry a gene it doesn’t show. Two bays that each carry red (E/e) and black (A/a) look identical to any other bay, but their foals can come out in three colours. These are the inheritance rules at work on two example horses (the breeding preview doesn’t show odds: it shows a few possible looks, drawn from the coat genes in each horse’s stud-book record):

#Champagne, silver, pearl and the white patterns

Seven more genes change the colour or add white patterns. They follow the same two-copy rules, and some hide: silver can’t show on a chestnut, pearl needs two copies (or one next to cream), and Pattern-1 does nothing without the leopard complex.

What the inheritance rules give for some example pairings, worked out by the game:

Each of these horses carries exactly the gene in its caption; the portraits draw it from the genes.

#Reading the Genetics panel

Every horse page has a Genetics panel: the stud-book view of the horse. Coat genes are public, so you can read them on anyone’s horse, including stallions at stud. Each line is one gene: its two copies in standard notation (the stronger one first) and what they do. A line marked (hidden copy) carries something the coat doesn’t show but the horse can pass on. Here is the panel for the bay sire above:

• Face and Legs name the markings (near and off are the horse’s left and right; fore and hind are front and back).
• Sabino shows the copies of Sabino-1; White tendency (low, medium or high) is how much white its genes carry, which is also what it tends to pass on.
• Build, the breed mix, Inbreeding (see Inbreeding & kinship), any quirks revealed in races and, if the horse has it, Fragile legs (inherited) (see Fragile legs).
• Body, pattern and performance genes: one line for each of the 14 genes above and on Breeds & body genes, with hidden copies marked; Size with what it does to the stats; Markings naming the colour and pattern genes the horse shows (and any the portrait doesn’t draw yet). Big heart reads “?/?” until the horse has raced or had a Pedigree Scan.
• Stat genes are not shown here: those stay hidden behind ranges. See Genetics & inheritance.