SLC36A1 gene

The SLC36A1 gene is responsible for the champagne coat color in horses.

Alleles

There are two currently known alleles.

The dominant CH-allele (champagne) dilutes black and red pigment, eyes, and causes freckling of the skin.

The recessive ch-allele leads to a regular coat color without dilution.

Mechanism

Pigment cells, called melanocytes, produce the pigments in the hair and skin of horses. The production of pigments can be influenced at different stages, changing the type (black or red) or the amount (dilutions/ white patterns) of pigment that is made.

The production of black and red pigment involves several different steps. Some of these steps are shared between the two, and some are unique to each pigment type. This is why certain genes will affect all base colors, while others only affect either red or black pigment: they affect different steps.

SLC36A1

Champagne is caused by a mutation of the SLC36A1 gene (Solute Carrier Family 36 Member 1). This gene isn't known to have any other effects on pigmentations in other species. However, its family member SLC36A2, better known as MATP, is responsible for cream in horses. The exact way SLC6A1 causes the champagne color isn't known, but it's possible the mutation affects the pH of melanosomes (organelles inside melanocytes where pigment is stored). This could, in turn, affect pigment production.

Colors

Champagne

Champagne is a dilution that lightens the base coat and eyes of horses and leads to the colors gold champagne, amber champagne and classic champagne.

Equine ColorsHannelore Roodhooft

Read more:
Color genes | MATP | PMEL17

Articles

1. Cook D, Brooks S, Bellone R, Bailey E.; Missense Mutation in Exon 2 of SLC36A1 Responsible for Champagne Dilution in Horses; PLOS Genetics (2008); Doi: 10.1371/journal.pgen.1000195