Cream (Dilution factor Horse)
The Cream mutation lightens the coat, mane and tail of the horse (dilution) by reducing the amount of pigment produced in the skin cells and hair.
The Cream mutation is inherited in an incomplete autosomal dominant way, which means that animals with only one copy (Cr/n) show a less pronounced lightening than animals with two mutant alleles (Cr/Cr). If one copy of the mutation is present, less light/red pigment (pheomelanin) is deposited. If two copies are present, less of the light and dark/black pigment (eumelanin) is deposited. Horses with two copies appear almost completely white.
Genetic Test: available in Shop
Also in the Dilution package
- The cream mutation reduces the amount of pigment produced in the skin cells and hair.
- If one copy of the mutation is present, less red/light pigment (pheomelanin) is produced.
- Horses with one copy have a lighter coat and slightly lighter brown eyes.
- If two copies are present, less of the light and black/dark pigment (eumelanin) is produced.
- Horses with two copies are almost white and have blue eyes.
- The base colour of the animal determines the respective lightened coat colour:
- In contrast to the Champagne dilution, Cream is an "old" mutation and is present in many breeds.
- If a horse carries a copy of Cream (Cr/n) and a copy of Champagne dilution (Ch/n), it looks similar to a horse with double Cream (white coat, blue eyes).
- Horses with the Cream dilution can additionally carry the mutation for Dun → emergence of colours like Smoky Dun, Dunskin and Dunolino.
Genotype and Lab Report
Inheritance: incomplete autosomal-dominant
→ Incomplete means that animals with only one copy (Cr/n) show a less pronounced phenotype than animals with two mutant alleles (Cr/Cr).
n/n = no copy of the Cream variant
Cr/n = one copy of the Cream variant
Slightly lightened coat colour, depending on the base colour of the horse 'Palomino' (from chestnut), 'Buchskin' (from bay) or 'Smoky Black' (from black).
Cr/Cr = two copies of the Cream variant
Strongly lightened coat colour, the horses are almost white with blue eyes, depending on the base colour of the horse 'Cremello' (from chestnut), 'Perlino' (from bay) or 'Smoky Cream' (from black).
→ Two copies of the Cream variant (Smoky cream, perlino, cremello) can be very difficult to distinguish. It is often necessary to do a genetic test to determine the base colours (black, bay, chestnut).
→ Smoky Black and Black may also be indistinguishable. Only genetic testing will then be able to determine whether a horse does have the Cream variant or not.
Mariat, D., Taourit, S., Guerin, G.: A mutation in the MATP gene causes the cream coat colour in the horse. Genetics Selection Evolution 35:119-33, 2003. Doi: 10.1051/gse:2002039.
Further information is available at Online Mendelian Inheritance in Animals.