Magical gene / spots and rings

Fawn

A soft-edged darkened topline with a single flowing line of small round spots running along it, neck to rump, and a pale underside to the tail. 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
FawnFwn/Fwn · Fwn/Fwc · Fwn/n · Fwn/Fwk
Black FawnFwk/Fwk · Fwk/Fwc · Fwk/n
Coloured FawnFwc/Fwc
Wild typeFwc/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 595 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
Fwn/FwnFawn0.006% — 1 in 16,667
Fwn/FwkFawn0.008% — 1 in 12,500
Fwn/FwcFawn0.008% — 1 in 12,500
Fwn/nFawn0.114% — 1 in 877
Fwk/FwkBlack Fawn0.008% — 1 in 12,500
Fwk/FwcBlack Fawn0.008% — 1 in 12,500
Fwk/nBlack Fawn0.008% — 1 in 12,500
Fwc/FwcColoured Fawn0.008% — 1 in 12,500
n/nWild type99.832%

Its gene carrot

The file

common/src/main/resources/horsegenetics/genes/fawn.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.fawn
Phasemagical — it adds signed colour in phase 3, after the pigment has resolved
Priority312 — where it sits in the one (priority, key) paint order
AllelesFwn · Fwk · Fwc · n
Varies per horse4 values drawn once off the expressing allele copy, so a foal that inherits the copy inherits the look
Built fromAXIS, SPOTS, STROKES, 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 Fwk 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.

Fawn

A darkened topline in the manner of sooty - a soft band down the crest, back and croup with no edge to it at either end - and, sitting on that dark band and nowhere else, one consecutive run of small round spots somewhere between the neck and the rump. Never two clusters with a gap between them, never a spiral or a pattern, just a flowing line of them, and all of them small. They keep off the face, the belly and the legs. Most fawn horses also carry a stylised eyeliner, a pangare-like lightening underneath, and a pale underside to the tail.

  1. the darkened topline the run sits on — AXIS, painted with TOWARD
  2. the flowing line of spots — SPOTS × STROKES × AXIS, painted with TOWARD
  3. eyeliner — SPOTS × AXIS, painted with TOWARD
  4. the underside of the tail — AXIS, painted with TOWARD

Black Fawn

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 darkened topline the run sits on — AXIS, painted with TOWARD
  2. the flowing line of spots — SPOTS × STROKES × AXIS, painted with TOWARD
  3. eyeliner — SPOTS × AXIS, painted with TOWARD
  4. the underside of the tail — AXIS, painted with TOWARD

Coloured Fawn

The same run of spots in a colour the line carries rather than in white. Fully recessive: it takes two copies, and a single copy beside the white allele shows white. It never gives blue eyes, whatever the white form does.

  1. the darkened topline the run sits on — AXIS, painted with TOWARD
  2. the flowing line of spots, in colour — SPOTS × STROKES × AXIS, painted with TOWARD
  3. eyeliner, in colour — SPOTS × AXIS, painted with TOWARD
  4. the underside of the tail, in colour — AXIS, painted with TOWARD

Wild type

No spots.

Paints nothing.