Magical gene / fields and regions

Stardust

Colour leaving the hair from two places at once - the base of the forelock and the tip of the tail - and creeping along the spine, with star-shaped dapples crowding the edge of wherever it has reached.

What it can come out as

Outcome	Carrying
Stardust	`Str/Str` · `Str/n` · `Str/Stt`
Coloured Stardust	`Stt/Stt`
Wild type	`Stt/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 893 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 pair	Shows as	How often
`Str/Str`	Stardust	0.004% — 1 in 25,000
`Str/Stt`	Stardust	0.016% — 1 in 6,250
`Str/n`	Stardust	0.076% — 1 in 1,316
`Stt/Stt`	Coloured Stardust	0.016% — 1 in 6,250
`n/n`	Wild type	99.888%

Its gene carrot

The file

common/src/main/resources/horsegenetics/genes/stardust.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.

Key	`horsegenetics.stardust`
Phase	magical — it adds signed colour in phase 3, after the pigment has resolved
Priority	269 — where it sits in the one `(priority, key)` paint order
Alleles	`Str` · `Stt` · `n`
Varies per horse	3 values drawn once off the expressing allele copy, so a foal that inherits the copy inherits the look
Built from	AXIS, CENTERLINE, SPOTS, TOWARD

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.

Stardust

Depigmentation only - nothing anywhere gets darker. It starts as a pale yellow-tinted patch at the base of the forelock, at the very end of the tail, or both. From the tail it works up toward the dock and then forward along the spine, spreading sideways over the croup and rump as it goes; from the forelock it works back across the poll and down the neck on a slope, and stops at the shoulder. It never reaches the barrel, the flank or the legs, and the mane is never fully taken - some base-coloured hair always survives in it. Around the edge of everything it has claimed sit the dapples: little radial stars of four to eight tapering points, crowded at the boundary and thinning inward, with fine ticking in the same band. Newly-pale hair carries a warm yellow cast; older ground is pure white.

pale ground along the spine and the croup — CENTERLINE × AXIS × AXIS, painted with TOWARD
the tail from the tip up, and the forelock — AXIS × AXIS, painted with TOWARD
star dapples crowding the edge of it — SPOTS × AXIS, painted with TOWARD
the crossing arm of each star — SPOTS × AXIS, painted with TOWARD

Coloured Stardust

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

pale ground along the spine and the croup, in colour — CENTERLINE × AXIS × AXIS, painted with TOWARD
the tail from the tip up, and the forelock, in colour — AXIS × AXIS, painted with TOWARD
star dapples crowding the edge of it, in colour — SPOTS × AXIS, painted with TOWARD
the crossing arm of each star, in colour — SPOTS × AXIS, painted with TOWARD

Wild type

No stardust.

Paints nothing.