Chapter 11: Colour genetics

• Hair types

• Colour types and colour genes

• Colour genes and biochemical function

• Examples from different domestic animals

Hair types

• Physical texture

• Ratio between under fur and guard hair

• Strength and durability of the fur

• Winter pelt and summer pelt

Hair types and genotypes Dominant Recessive Wire haired W- Straight haired ww Short haired L- Long haired ll Guard hair M- Mole mmHair N- Hairless nn

Examples of hair types

Wire haired

Long hair

HairlessMole guard hair

Colour types in mammals and colour genes

• Melanin is the stain of the hairEumelanin black and brownPhaeomelanin yellow and red

• Air bubbles White

• Melanin is produced in a cell type, called melanocytes

Important colour loci in domestic animals

• Agouti locus: A-locus • Brown locus: B-locus brown whelps • Albino locus: C-locus • Dilution locus: D-locus• Extension locus: E-locus yellow whelps • Pink eyed dilution locus: P-locus• X-linked Orange locus: O-locus

Colour genes and biochemical function

• Part of the melanin synthesis (biochemical synthesis)

• Regulate melanin production (hormonal)• Regulate the morphology of the melanocytes • Regulate number of melanocytes

The genes can be divided into the following groups:

Colour genes: biochemical function

Colour genes in Danish swine breeds

Dominant Recessive

Dominant white I- Coloured ii Black E- Red ee White belt B- Uniform bb

Yorkshire Landrace Hampshire Duroc

Colour genes in Danish cattle breeds

Dominant Recessive

Black E- Red ee Uniform S- Spotted ssWhite head H- Uniform hh

Black & white Red Danish Hereford

Colour genes in the horse

Colour genes in the horse

Colour genes in the dog

Dominant Recessive

Black and tan at- Red aaBlack B- Brown bbDark C- Light cch cch

Black D- Silver ddBlack E- Red (yellow)ee Uniform mm Merle M-Airedale

TibetanLabrador

Colour genes in minkColour types, single

Mutant nameMutant genotype

Wild type, Standard

White Albino, red eyed cc CC

Hedlund White, deaf

hh HH

Grey Aleutian, bluish aa AA

Silver Blue, grey pp PP

Steel Blue psps PP

Brown Royal Pastel bb BB

Moyl mm MM

American Palomino

kk KK

Bicoloured Black Cross Ss ss

Colour genes in mink

Colour genes in cats

Colour genes in other species

• Sheep

• Rabbit

• Mouse