In to previous articles I started a discussion of coat color genetics in horses. Previously we have talked about base colors bay, chestnut, and Black, and the champagne, and cream dilutions. In todays article I will look at grey, pearl, and silver dilutions in horse coat color.
Lets take a look at Grey coat color in Horses.
The Grey gene in horses is a dominant gene, only one allele for grey is necessary for the horse to grey with age. Grey horses can be born any color, and will gradually grey over time. This is most commonly seen in the Lippizaner breed. They are born bay or black and will be almost completely white by the age of 10. Greying in horses is usually first noticed around the eyes and nose, foals that will turn grey later in life, will usually exhibit greying of the face when they shed the foal coat.
They Grey Horses Genotype looks like this: N/G or G/G
Horses with N/G will be grey and have a 50% chance of producing grey offspring.
Horses with GG will be grey and will produce grey offspring.
Pearl Dilutions
The Pearl dilution has been found in horses of Spanish decent (Andalusians, Lusitano's, Quarter Horses, and Paints) The Quarter Horse and Paint Horse trace their genetics back to the Spanish breed and it is thought, that this is where they received the gene for Pearl Dilution.
The Pearl dilution is a rare and recessive dilution that requires both recessive alleles for the color to be expressed. When expressed on a chestnut horse the body is a pale gold color with matching mane and tail. The eyes will be blue/green in color. One allele on bay or black base color does not produce a color change in the body color. Genotype letters used for this dilute are Prl.
Silver Dilutions
The Silver Dilution in horses is a dominant trait that effects black based horses. This dilution will on be seen in Bays, and Blacks, but it has no effect on Chestnut horses. This dilution is commonly seen in Morgan's, Rocky Mountain horses, Shetland's, Icelandics, and other related breeds.
A Bay horse receiving one or two copies of the gene (Z) will have a flaxen mane and tail, the black points on the legs lightened.
A Black horse receiving one or two copies of the gene (Z) will be chocolate with a flaxen mane and tail.
Horses come in a wide variety of colors, In these articles I have only discussed base colors and base color dilutions. Paints, Appaloosa, POA's, and many other breeds have unique genetics that allow for their colorful markings. Join me again for a discussion of color patterns in horses.
To Find out your Horses Genotype and projected foal color use the Animal Genetics Calculator
References:
Terminology
Homozygous means that two alleles are present for the same gene, example EE ( presence of two dominant alleles).
Heterozygous means that of the two alleles present one is dominant (E) and one recessive (e).
Dominant alleles will allow a genotype to be physically expressed in the phenotype (what the horse looks like).
Comments
Nice article. I used to work with horses and this brings back good memories.
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