Real Horse Coat Genetics

Many games are based on horse coat genetics that occur in real life. Here is an attempt to help understanding real horse genetics and a guide for horse coat.

However, games may take some artistic freedom from real genetics, as well as the whole horse coat genetics is not fully known at the game creation and research is ongoing in this field. For these reasons, it may be helpful to consult the game page if something differs from reality.

Careful! This page is not an exhaustive list of horse coat genes. It is only a simplification for people that does not have genetics knowledge and want to understand in-game genetics.

For section, gene description and table with genetics, name, description and image of the horse coat if possible

How to read this guide
Here is a little guide to help understanding genetics in game that use real horse coat genetics.

Genes are ordered depending on their action.

Below is the template for coat genetics. If there is no need to know the gene, it will be noted with an asterisk.

Basics in genetics
Horse coats are detemined by the combined actions of multiple genes. Each gene comes in two copies, called alleles. If both alleles for a gene are identical, a horse is homozygous for this gene; and if the two alleles are different, it is heterozygous.

An allele is dominant if it is expressed even with a single copy. On the other hand, an allele that needs two copies is called recessive. Dominant alleles are noted in upper case, and recessive alleles are noted in lower case.

For convenience, the derivated allele (ie the one which is not usual) is called the "gene". For example, a red dun horse is said it has the Dun gene.

Some explanation by Jennifer Hoffman.

Base coat
Every horse have Extension and Agouti genes, which work together to create the horse's color. All horses have some combination of E, e, A and a regardless of their color. Extension determines the color; E is dominant extension coding for black pigment, and e recessive for red pigment only. Agouti changes the color repartition; A for dominant agouti which moves black pigment to extremities, and a for recessive agouti for uniform black coat.