The Pearl gene, also known as the "Barlink factor", is a

dilution gene A dilution gene is any one of a number of genes that act to create a lighter coat color in living creatures. There are many examples of such genes: General Diluted coat colors have melanocytes, but vary from darker colors due to the concentration ...

at the same locus as the

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

, 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 or less; some have been clocked at speeds up to ...

American Paint Horse The American Paint Horse is a breed of horse that combines both the conformational characteristics of a western riding, western stock horse with a pinto horse, pinto spotting pattern of white and dark equine coat color, coat colors. Developed f ...

, and Peruvian Paso." 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 for ...

and Pura Raza Española, PRE, often referred to as 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 In genetics, dominance is the phenomenon of one variant (allele) of a gene on a chromosome masking or overriding the effect of a different variant of the same gene on the other copy of the chromosome. The first variant is termed dominant and ...

. If there is only one copy of the gene, it has no effect on

black Black is a color that results from the absence or complete absorption of visible light. It is an achromatic color, without chroma, like white and grey. It is often used symbolically or figuratively to represent darkness.Eva Heller, ''P ...

bay A bay is a recessed, coastal body of water that directly connects to a larger main body of water, such as an ocean, a lake, or another bay. A large bay is usually called a ''gulf'', ''sea'', ''sound'', or ''bight''. A ''cove'' is a small, ci ...

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

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, i ...

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, i ...

. 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 Genetic testing, also known as DNA testing, is used to identify changes in DNA sequence or chromosome structure. Genetic testing can also include measuring the results of genetic changes, such as RNA analysis as an output of gene expression, or ...

. 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 equidae, 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 th ...

named My Tontime, and her grandson, the

stallion A stallion is an adult 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, "cre ...

Barlink Macho Man, a chestnut

splashed white Splashed white or splash is a horse coat color pattern in the " overo" group of spotting patterns that produces pink-skinned, white markings. Many splashed whites have very modest markings, while others have the distinctive "dipped in white pai ...

."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 is a variant of the sequence of nucleotides at a particular location, or Locus (genetics), locus, on a DNA molecule. Alleles can differ at a single position through Single-nucleotide polymorphism, single nucleotide polymorphisms (SNP), ...

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

References

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