Flaxen is a genetic trait in which the mane and

tail The tail is the section at the rear end of certain kinds of animals’ bodies; in general, the term refers to a distinct, flexible appendage to the torso. It is the part of the body that corresponds roughly to the sacrum and coccyx in mammals, r ...

of chestnut-colored horses are noticeably lighter than the body coat color, often a golden

blonde Blond (male) or blonde (female), also referred to as fair hair, is a hair color characterized by low levels of the dark pigment eumelanin. The resultant visible hue depends on various factors, but always has some yellowish color. The color can ...

shade. Manes and tails can also be a mixture of darker and lighter hairs. Certain

horse breed A horse breed is a selectively bred population of domesticated horses, often with pedigrees recorded in a breed registry. However, the term is sometimes used in a broader sense to define landrace animals of a common phenotype located within a lim ...

s such as the

Haflinger The Haflinger, also known as the Avelignese, is a horse breed, breed of horse developed in Austria and northern Italy (namely Hafling in South Tyrol region) during the late 19th century. Haflinger horses are relatively small, are always chestnu ...

carry flaxen chestnut coloration as a breed trait. It is seen in chestnut-colored animals of other horse breeds that may not be exclusively chestnut. The degree of expression of the trait is highly variable, with some chestnuts being only slightly flaxen while others are more so. Flaxen was once thought to be produced by a

recessive 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 t ...

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 ...

, based on preliminary studies, proposed as ''F^f'' for ''flaxen''. However, more recently it is thought that it may actually be

polygenic A polygene is a member of a group of non-epistatic genes that interact additively to influence a phenotypic trait, thus contributing to multiple-gene inheritance (polygenic inheritance, multigenic inheritance, quantitative inheritance), a type of ...

, influenced by multiple genes. Some chestnut horses that do not exhibit much flaxen may nonetheless produce strongly flaxen offspring. Studies on Morgan horses have indicated that the flaxen trait is inherited. One found that flaxen chestnut horses mated with other flaxen chestnut horses consistently produce only flaxen chestnuts, which, if

Mendelian inheritance Mendelian inheritance (also known as Mendelism) is a type of biological inheritance following the principles originally proposed by Gregor Mendel in 1865 and 1866, re-discovered in 1900 by Hugo de Vries and Carl Correns, and later popularize ...

is assumed, would make it a recessive gene. Flaxen does not affect

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 ...

or bay horses, only chestnuts. However, as there are examples of flaxen chestnuts born to parents that are black or bay, it may be masked in darker-colored horses but still passed on to their offspring.

Flaxen mimics

Coloration of a light mane and tail with darker body color may be created by other genetic mechanisms known as dilution genes, most of which can be detected by DNA testing. The most common is

palomino Palomino is a genetic color in horses, consisting of a gold coat and white mane and tail; the degree of whiteness can vary from bright white to yellow. Genetically, the palomino color is created by a single allele of a dilution gene called t ...

, created by one copy of 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 ...

acting on a chestnut coat, resulting in a gold-colored coat with a white or cream colored mane and tail. Deep gold palominos may be hard to distinguish from light chestnuts with significant expression of flaxen, but genetic tests can aid determination of color. 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 ...

acting on a chestnut coat may also produce a horse with a gold coat and ivory mane and tail, distinguishable from palomino by freckled skin and light-colored eyes. In most cases, a chestnut with flaxen can be distinguished from other colors by the presence of some reddish, chestnut hairs in the mane or tail. The silver or

silver dapple gene The silver or silver dapple (''Z'') gene is a dilution gene that affects the black base coat color and is associated with Multiple Congenital Ocular Abnormalities. It will typically dilute a black mane and tail to a silvery gray or flaxen color ...

acts only on black hair. On a black base coat, it lightens the body to a brown color and the mane/tail to a cream or silver shade; on a bay base coat, it lightens the mane and tail to cream or silver. It does not affect chestnut (red) coloring. A genetic test exists for the silver gene.

References

{{Equine coat colors Horse coat colors