🐾 Pets Alpha

Horse Coat Colors & Genetics

From basic bay to champagne dunalino — the complete visual guide to how horse color genetics actually work. Every horse color starts with just two pigments (black and red) modified by a handful of genes. Complete guide: the Extension, Agouti, Cream, Dun, Roan, Gray, Champagne, Silver, and Pearl genes explained simply.

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📑 Table of Contents

  1. The Two Base Pigments: Black & Red
  2. Extension (E/e) — Red/Black Switch
  3. Agouti (A/a) — Bay or Not Bay
  4. Cream Gene — Palomino, Buckskin, Smoky, Cremello
  5. Dun Gene — Dorsal Stripe & Primitive Markings
  6. Roan — White Hairs Mixed In
  7. Gray — Progressive Whitening
  8. Pinto Patterns: Tobiano, Overo, Tovero, Sabino

🎨 The Two Base Pigments: Black & Red

Every horse color starts with just two pigments: eumelanin (black) and pheomelanin (red). All the beautiful variations — bay, palomino, buckskin, cremello, dun, roan, gray — come from modifier genes acting on these two base pigments. The Extension gene (MC1R) determines whether a horse can produce black pigment or only red. The Agouti gene (ASIP) determines WHERE black pigment is distributed. All other genes modify the result.

🧬 The Major Modifier Genes

GeneEffectExample Colors
Cream (Cr)Dilutes red→gold, black→brown (1 copy) or both→cream (2 copies)Palomino, Buckskin, Smoky Black, Cremello, Perlino
Dun (D)Lightens body, adds dorsal stripe + leg barring + shoulder stripeBay Dun, Red Dun, Grullo (black dun)
Roan (Rn)White hairs mixed evenly through body; head/legs stay darkRed Roan, Bay Roan, Blue Roan
Gray (G)Progressive whitening — born dark, grows lighter with ageSteel Gray, Dapple Gray, Fleabitten Gray
Champagne (Ch)Dilutes coat + pink skin + amber/hazel eyesGold Champagne, Amber Champagne, Classic Champagne
Silver (Z)Dilutes BLACK pigment only — creates "chocolate" horsesSilver Bay, Silver Dapple, Silver Black

🧬 Fun fact: The Cream gene is an incomplete dominant — one copy dilutes, two copies double-dilute. This means a Palomino (one cream on chestnut) bred to a Cremello (two creams) produces 50% Palomino + 50% Cremello — but two Palominos bred together produce only 25% Cremello. Understanding this is key for color breeders.