Magical gene / lines and strokes

Opaline Zebra

A full set of stripes - round the barrel, across the face, and down the spine - on a ground that is opal rather than white. A third allele carries the same marking worked in greys instead of white - dark where the pale form is light, and the same number of steps.

What it can come out as

OutcomeCarrying
Opaline ZebraOpz/Opz · Opz/Opc · Opz/n · Opz/Opk
Opaline Zebra, blackOpk/Opk · Opk/Opc · Opk/n
Opaline Zebra, colouredOpc/Opc
Wild typeOpc/n · n/n

How each one is actually drawn - region by region, and the layers it is built from - is on the coding tab.

Crossing two of them

Finding one

About 1 in 1,786 wild horses is born showing this. That is the whole of the supply: catch one, or make one with the carrot below. Breeds set their own pools and a breed built around this gene will carry it far more often than the wild population does.

Wild pairShows asHow often
Opz/OpzOpaline Zebra0.002% — 1 in 50,000
Opz/OpkOpaline Zebra0.0027% — 1 in 37,495
Opz/OpcOpaline Zebra0.0027% — 1 in 37,495
Opz/nOpaline Zebra0.038% — 1 in 2,632
Opk/OpkOpaline Zebra, black0.0027% — 1 in 37,495
Opk/OpcOpaline Zebra, black0.0027% — 1 in 37,495
Opk/nOpaline Zebra, black0.0027% — 1 in 37,495
Opc/OpcOpaline Zebra, coloured0.0027% — 1 in 37,495
n/nWild type99.944%

Its gene carrot

The file

common/src/main/resources/horsegenetics/genes/opaline_zebra.json — a data-driven gene, not a Java class. It is listed in the index.json beside it and registered by Genes' class initialiser at startup.

Keyhorsegenetics.opaline_zebra
Phasemagical — it adds signed colour in phase 3, after the pigment has resolved
Priority380 — where it sits in the one (priority, key) paint order
AllelesOpz · Opk · Opc · n
Varies per horse6 values drawn once off the expressing allele copy, so a foal that inherits the copy inherits the look
Built fromCENTERLINE, PARTS, TOWARD, WAVES

Why it is built this way

Imported from the magic-gene intake, 2026-09-08. The pale ground goes on first and the stripes over it, which is the honest way round: a zebra is a pale animal with dark stripes, and painting it the other way makes the stripe spacing the thing you notice.

Barrel strokes run along Z - round the horse rather than along it. On the face, Z is across the nose, which is the direction facial striping actually runs.

The black allele is the white one with the light taken out of it, and it sits one rung under white in the dominance series - so every combination that existed before it keeps the outcome it had, and only the pairs carrying Opk are new. The re-toning is a mapping rather than a repaint: every achromatic target moves into the dark end of the scale keeping its order and its spacing, and every SATURATED one is left alone, because that colour is the gene rather than its lightness.

What it paints

Each outcome, described the way the gene file describes it, and then the layers that draw it in the order they are painted. The prose is the part a reader checks a bake against; the list underneath is what the engine actually did.

Opaline Zebra

The pale ground goes on first and the stripes over it, which is the honest way round for a zebra: what you are looking at is a white horse with black on it, not a black horse with white on it. The stripes are WAVES rather than STROKES because only WAVES repeats evenly - strokes wander, and a zebra whose stripes wander is a brindle.

  1. the ground between the stripes — PARTS, painted with TOWARD
  2. stripes round the barrel — WAVES, painted with TOWARD
  3. finer ones across the face — WAVES, painted with TOWARD
  4. and a dorsal line down the spine — CENTERLINE, painted with TOWARD

Opaline Zebra, black

The same marking as the white form with the light taken out of it: the same 2 steps, moved to the dark end of the scale.

  1. the ground between the stripes — PARTS, painted with TOWARD
  2. stripes round the barrel — WAVES, painted with TOWARD
  3. finer ones across the face — WAVES, painted with TOWARD
  4. and a dorsal line down the spine — CENTERLINE, painted with TOWARD

Opaline Zebra, coloured

The same stripes on a ground the line carries a colour for - which is what makes it opaline rather than plain. Fully recessive.

  1. the ground between the stripes — PARTS, painted with TOWARD
  2. stripes round the barrel — WAVES, painted with TOWARD
  3. finer ones across the face — WAVES, painted with TOWARD
  4. and a dorsal line down the spine — CENTERLINE, painted with TOWARD

Wild type

No stripes.

Paints nothing.