Magical gene / colour modifiers

Bloodstained

Red gathers along the bottom edge of the horse's markings - inside the white rather than around it, and under every red the coat already had. It reads as something that ran down and settled, because that is exactly how the mask is built.

What it can come out as

Outcome	Carrying
Bloodstained	`Bst/Bst`
Wild type	`Bst/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 2,500 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
`Bst/Bst`	Bloodstained	0.04% — 1 in 2,500
`n/n`	Wild type	99.96%

Its gene carrot

The file

common/src/main/resources/horsegenetics/genes/bloodstained.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.bloodstained`
Phase	magical — it adds signed colour in phase 3, after the pigment has resolved
Priority	612 — where it sits in the one `(priority, key)` paint order
Alleles	`Bst` · `n`
Varies per horse	2 values drawn once off the expressing allele copy, so a foal that inherits the copy inherits the look
Built from	LUMA, 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.

Bloodstained

Two copies. Every white marking the horse carries is stained red along its lower inside edge - not a rim round the whole marking, the bottom of it, as though something had run down and collected where the white stops. A second, darker line sits right at the boundary. The same thing happens under everything the coat made red, so a chestnut is stained along the underside of itself and a black with four socks is stained only in the socks. The one-sidedness is the whole gene, and it is a real measurement rather than a shading trick: the mask grows the non-white upward into the marking, so the band it leaves is the part of the marking that has something under it. A marking with nothing under it - the very bottom of a leg - stains all the way through.

inside every white marking, along its lower edge - where it pools — LUMA × LUMA inverted, painted with TOWARD
the darker line right at the bottom of that band — LUMA × LUMA inverted, painted with TOWARD
and along the lower edge of everything the coat made red — LUMA × LUMA inverted, painted with TOWARD

Wild type

No staining. A single copy shows nothing at all.

Paints nothing.