Magical gene / fields and regions

Shark

A single fin-shaped pale field standing on the withers and on the top of the base of the neck, with a tapering band running on up the crest to the poll. 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
SharkShk/Shk · Shk/Shc · Shk/n · Shk/Shbk
Black sharkShbk/Shbk · Shbk/Shc · Shbk/n
Coloured sharkShc/Shc
Wild typeShc/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
Shk/ShkShark0.002% — 1 in 50,000
Shk/ShbkShark0.0027% — 1 in 37,495
Shk/ShcShark0.0027% — 1 in 37,495
Shk/nShark0.038% — 1 in 2,632
Shbk/ShbkBlack shark0.0027% — 1 in 37,495
Shbk/ShcBlack shark0.0027% — 1 in 37,495
Shbk/nBlack shark0.0027% — 1 in 37,495
Shc/ShcColoured shark0.0027% — 1 in 37,495
n/nWild type99.944%

Its gene carrot

The file

common/src/main/resources/horsegenetics/genes/shark.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.shark
Phasemagical — it adds signed colour in phase 3, after the pigment has resolved
Priority259 — where it sits in the one (priority, key) paint order
AllelesShk · Shbk · Shc · n
Varies per horse4 values drawn once off the expressing allele copy, so a foal that inherits the copy inherits the look
Built fromAXIS, CENTERLINE, NOISE, TOWARD

Why it is built this way

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 Shbk 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.

Shark

One field, and only one: a sickle standing on the topline over the withers, its apex set forward of the middle of its base, its back edge scooped hollow and its front edge straight or slightly bellied. It stands on the base of the neck, which goes pale over the crest and down the upper side but never onto the throat - that much of the neck is part of the marking, not a separate one. Crisp along the top and the back edge, softer underneath. Most sharks also carry a narrow band running forward along the crest from the apex to the poll.

  1. the fin on the withers — AXIS × AXIS × NOISE, painted with TOWARD
  2. the base of the neck the fin stands on, clear of the throat — AXIS × AXIS × NOISE, painted with TOWARD
  3. the band on up the crest — CENTERLINE × AXIS, painted with TOWARD

Black shark

The same marking as the white form with the light taken out of it: a single near-black tone.

  1. the fin on the withers — AXIS × AXIS × NOISE, painted with TOWARD
  2. the base of the neck the fin stands on, clear of the throat — AXIS × AXIS × NOISE, painted with TOWARD
  3. the band on up the crest — CENTERLINE × AXIS, painted with TOWARD

Coloured shark

The same fin in a colour the line carries. Fully recessive: two copies, and a single copy beside the white allele shows white. It never gives blue eyes.

  1. the fin on the withers, in colour — AXIS × AXIS × NOISE, painted with TOWARD
  2. the base of the neck the fin stands on, clear of the throat — AXIS × AXIS × NOISE, painted with TOWARD
  3. the band on up the crest, in colour — CENTERLINE × AXIS, painted with TOWARD

Wild type

No fin.

Paints nothing.