The Pearl gene, also known as the "Barlink factor", is a dilution gene at the same locus as the

cream gene The cream gene is responsible for a number of horse coat colors. Horses that have the cream gene in addition to a base coat color that is chestnut will become palomino if they are heterozygous, having one copy of the cream gene, or cremello, if ...

, which somewhat resembles the

and the

champagne gene The champagne gene is a simple dominant allele responsible for a number of rare horse coat colors. The most distinctive traits of horses with the champagne gene are the hazel eyes and pinkish, freckled skin, which are bright blue and bright pink ...

but is unrelated to champagne. It is a somewhat rare dilution gene found in the

American Quarter Horse The American Quarter Horse, or Quarter Horse, is an American breed of horse that excels at sprinting short distances. Its name is derived from its ability to outrun other horse breeds in races of a quarter mile or less; some have been clocked at s ...

American Paint Horse The American Paint Horse is a breed of horse that combines both the conformational characteristics of a western stock horse with a pinto spotting pattern of white and dark coat colors. Developed from a base of spotted horses with Quarter Hors ...

, and

Peruvian Paso The Peruvian Horse is a breed of light saddle horse known for its smooth ride. It is distinguished by a natural, four-beat, lateral gait called the ''paso llano.'' This breed is protected by the Peruvian government through Decree number 25919 o ...

." Introduction to Coat Color Genetics"
''from'' Veterinary Genetics Laboratory, School of Veterinary Medicine, University of California, Davis. Web Site accessed March 27, 2008 The same mutation appears in

Iberian horse The Iberian horse is a designation given to a number of horse breeds native to the Iberian peninsula. At present, some breeds are officially recognized by the FAO,

breeds such as the

Lusitano The Lusitano, also known as the Pure Blood Lusitano or PSL (''Puro Sangue Lusitano''), is a Portuguese horse breed. Horses were known to be present on the Iberian Peninsula as far back as 20,000 BC, and by 800 BC the region was renowned fo ...

and Andalusian. The existence of the pearl gene in Quarter Horses and Paints is probably because these breeds have some Iberian ancestors. It is a recessive gene. If there is only one copy of the gene, it has no effect on

black Black is a color which results from the absence or complete absorption of visible light. It is an achromatic color, without hue, like white and grey. It is often used symbolically or figuratively to represent darkness. Black and white have o ...

, bay or

chestnut The chestnuts are the deciduous trees and shrubs in the genus ''Castanea'', in the beech family Fagaceae. They are native to temperate regions of the Northern Hemisphere. The name also refers to the edible nuts they produce. The unrelat ...

horses. If there are two copies, it lightens red coats to a pale, uniform apricot color that includes body, mane and tail and creates pale skin. Because of this effect, when research was underway to locate the specific gene involved, it was at one time referred to as the "apricot" gene. The Pearl gene is also known to interact with the

to enhance its effects and, in horses with only one copy of the cream allele, to create "pseudo-double dilutes" sometimes called pseudo-

cremello The cream gene is responsible for a number of horse coat colors. Horses that have the cream gene in addition to a base coat color that is chestnut will become palomino if they are heterozygous, having one copy of the cream gene, or cremello, if ...

s or pseudo-

smoky cream The cream gene is responsible for a number of horse coat colors. Horses that have the cream gene in addition to a base coat color that is chestnut will become palomino if they are heterozygous, having one copy of the cream gene, or cremello, ...

. A pseudo-double dilute will often have pale skin and blue or green eyes. Unlike the double cream dilute and the Pearl-cream pseudo dilute the double Pearl dilute typically has dark tan eyes. It is difficult if not impossible to tell a double cream dilute from a Pearl-cream pseudo dilute without genetic testing. Pearl is found at '' SLC45A2'' (also called ''MATP''), the same locus as cream, sunshine, and snowdrop. In the

breed, the dilution was called the "Barlink factor" because it was linked to a

mare A mare is an adult female horse or other equine. In most cases, a mare is a female horse over the age of three, and a filly is a female horse three and younger. In Thoroughbred horse racing, a mare is defined as a female horse more than four ...

named My Tontime, and her grandson, the

stallion A stallion is a male horse that has not been gelded (castrated). Stallions follow the conformation and phenotype of their breed, but within that standard, the presence of hormones such as testosterone may give stallions a thicker, "cresty" nec ...

Barlink Macho Man, a chestnut splashed white."Paint horse legends: Genetics
Web page accessed March 27, 2008 Initially, the gene in Paints and Quarter Horses was thought to be a different

allele An allele (, ; ; modern formation from Greek ἄλλος ''állos'', "other") is a variation of the same sequence of nucleotides at the same place on a long DNA molecule, as described in leading textbooks on genetics and evolution. ::"The chro ...

than that in the Iberian breeds, but research demonstrated that it was the same gene.

References

Horse coat colors {{Improve categories, date=April 2021