Basic Colour Genetics
This page is designed as a basic guide to colour genetics, hopefully everyone who reads it will have a better understanding of the way colour genetics works and the correct colours used to describe a horses coat colour.
To work out the possible colour combinations for a foal try using the Foal Colour Calculator
Base Colours
There are only 2 base colours in horses, Black & Chestnut. Every colour is built from these 2 bases, no matter how the horses colour may appear.
Black is dominant over chestnut. A black horse can therefore carry the chestnut gene but a chestnut cannot carry the black gene.
Colour Dilutions
Dun, Silver, Cream & Champagne are colour dilutors. They dilute the horses base colour to appear as a complety different colour. Dilute genes are dominate and therfore one parent MUST carry the gene for the foal to receive it. For example, you CANNOT get a dun foal without one parent being a true dun.
Some dilute genes will only show on certain base colours.
Dun - will show on any colour base, it will put a crisp clear dorsal stripe (not a faded or unclear one) down the horses back, leg barring, shoulder barring, face masking, cobwebbing etc. A lot fo foals are born with 'dun type' markings, but these will usualy fade at first foal coat shed. These are not 'true' duns, it is a camoflauge foals are born with.
Silver - will dilute black pigment only, so will not show up on a chestnut base. A lot of silver horses are called taffys or silver dapple. The Silver gene can be carried by a chestnut base horse as it does not affect red pigment so therfore will not change the physical appreance of a chestnut. A chestnut horse with a blone mane and tail is NOT a silver or a taffy.
Cream - will only dilute brown & chestnut bases in a single dose, which is why buckskins keep there black legs, mane and tail, but in a double dose will dilute all bases.
Champagne - will dilute both base colours & is a dominant gene. Champagne horses are born with light coloured eyes, which can end up blue, hazel, green or amber. They are born with pink skins that darkens to a purplish brown at maturity. A Champagne horse has a metallic sheen to there coat. Most champagne foals are born with a darker coat that lightenes with age, whereas a normal foal will be born light and darken with age.
Colour Modifiers
These genes modify a horses colour, it does not dilute it.
Bay - the Agouti gene is responsible for making a black horse bay. This gene restricts the black pigment to the legs, mane, tail & ear tips. Agouit also makes a horse appear brown. Agouti is a dominant gene but can be hidden under a chestnut base, as chestnut has cannot make black pigment and therefore can hide the agouti gene. This is why you will sometimes see a black x chestnut mating produce a bay foal.
Grey - is dominant, it works by slowing striping the pigment from the horses coat. Grey has the ability to cover every other colour, pattern or dilution. One parent must be grey to get a grey foal.
Flaxen - modifys the mane and tail on a chestnut to blonde/white colour.
Pangrae - makes the nose, flanks, underneath side etc of bays/chestnuts go cream coloured. Very commonly seen in the halflinger breed.
Sooty - occours on both base colours, and works by darkening certain ares of the horses body. A chocolate palomino is a palomino with sooty. A dirty coloured buckskin (commonly called duns which they are not!) are also carring the sooty gene.
Colour Patterns
All white patterns are superimposed over the coloured parts of the horse. The white & coloured parts on a horse are not related and act individually from each other. The main key to remember is its not the amount of white a horse has but how it is placed.
White colour patterns: Appaloosa, sabino, frame, classic roan, rabicano, splashed white, tobiano. You can also get a mix of these patterns on the same horse.
Please visit Equine Colour for pictures and more detailed information. :)
