horse coat colors 말의 털 색깔

A5. Principal horse coat colors and markings, their inheritance

Monogenic (qualitative) characteristics of the horse – coat colors

Basic colors: Black, bay (brown), chestnut (=red),+ white

Modified variants: Grey, roan and dun color dilution, cream, pearl, champagne, silver dapple

White color: roan (mixture), pinto (spotted), leopard, dominant white, white markings (splashed white)

​Rules of Mendelian inheritance are valid for coat colors

Majority of color genes are dominant!

Roan color : Intermediate inheritance (=dark & white mixed)

Coat color may be a breed characteristic like in Friesian, Norwegian Fjording , Lipizzan, Haflinger, Knabstrup

Some color genes are molecular genetically undetectable

(dun, chestnut, tobiano, overo spotted)

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A - Agouti allele locus:

Distribution of black colored hair (eu + phaeomelanin)

ASIP= agouti signaling protein

AA, Aa (E-): brown, bay

Agouti is polymorphic

aa: black color. Uniform (Friesian)

AtAt : black brown (morgan)

E - locus- Melanin Extension/non-extension

Extension of dark and red pigments (red, chestnut, sorrel -> ee = ability to produce black pigment in skin, but appears red in hairs

EE, Ee= produce black pigments in skin and hair (bay= in points, black= in overall)

ee= skin has black pigment, hair has red pigment. genotype is always red.

ee= chestnut, (Shetland, pony, gidran)

​G - Grey (dominant) locus

Exclusion of pigment from hair over time

(born dark, lightens with age  progressive greying)

grey – syntaxin gene 17= STX 17

GG, Gg = dosis effect, early and late greying.

gg = no progressive silvering with age

R - Roan, co-dominant, intermediate locus.

Mixing of dark & light hairs:

Black, blue, bay & red roan

On branding sites- black hairs!

Appaloosa characteristics (leopard) may be related to the roan gene. Complex inherited, combinations of polymorphic alleles (LP1, LP2)

​D - Dilution/dominant locus

The basic colors are diluted: many variations- bay, brown, blue, (wolf, mouse, grey), yellow, orange, red, apricot, silver-dun, wild colors. Modifier: cremello allele

Dun horses: norwegian fjord horse and tarpan (grey/brown)

DD, Dd: slight dilution but points remain dark!

W - White, inborn dominant locus

Inability to form pigment, congenital dominant, pleiotropic, epistatic

WW homozygotes  embryonic lethal

Ww heterozygote  normal white, no pigment in skin, hair, born white

ww  pigmented, any color.

C - Color: albino pigment (tyrosianse) locus (rare)

CC- fully pigmented

CCcr- from BUCKSKIN and lighter/ chestnut PALOMINO (golden)

PALOMINO (eeCCcr)= gold, cream. color of the palomino can be changed due to environmental effects.

S - Spotting (Appaloosa: blanket, marble, leopards, snowflake, spot)

P - Piebald/skewbald

O allele - Overo spotted= dominant, lethal white foal

T - Tobiano = dominant (white spots, pink skin )