Fanciers of Belted Galloway cattle are blessed with a choice of several colors --black, red, and dun. Belting, a form of spotting, is controlled by the (Bt) locus, and occurs in areas where the skin or hair lacks melanocytes. The occurences of white-tip tails & feet is possibly controlled by the recessive (s) allele. While belting is considered autosomal dominant, it can be incomplete or nonexistent when Belties are crossed with solid Galloways. This may result from many Galloways carrying a wild-type, nonspotting (S+) allele. 

Coat color in cattle is determined by the presence or absence of two pigments called melanins. In Belties these two pigments are eumelanin (black) and phaeomelanin (red). Eumelanin is a black pigment but can look brown or grey in low levels. Phaeomelanin is a red pigment which can look orange to yellow in low levels. When neither is present hair is white.

Melanocyte Stimulating Hormone Receptor Gene (MSHr), also called the Melanocortin Receptor 1 gene (MC1r), is the source of all black- or red-hided Belties. This gene has two common alleles, dominant (ED) and recessive (e). In addition a less common allele occurs (E+, also called ‘wild-type’). An animal with (ED) present is always black. This allele is dominant to (E+) and (e). Cattle that are (e/e) are the recessive genotype red. (Note: Upper case notates dominance, lowercase recessive.)

The Extension locus (E) is responsible for most color variation in Belties. Three alleles control the visible color:  (ED) dominant black, (E+) wild-type (combinations of black/red/brown), and (e) recessive red.  Geneticists usually indicate order of dominance of the three alleles by writing ED > E+ > e. Using this notation, a homozygous black genotype would be (ED/ED).  In contrast a heterozygous wild-type/red genotype is written as (E+/e). (ED) is not responsive to Agouti (A).

Extension regulates the levels of tyrosinase. High concentrations of this enzyme result in production of eumelanin (black pigment), while low concentrations of this enzyme result in the production of phaeomelanin (red pigment). The ancestors of Belties, the Auroch, are now thought to have had a single common allele for this gene (E+). When wild-type allele (A+) is present on the Agouti locus in conjunction with wild-type (E+)at the Extension locus, a dark red/black color is produced.

Sheila M. Schmutz, Ph.D., states in her paper “Genetics of Coat Color in Cattle” that E+ appears to be a “neutral” allele in most breeds and we think (ED/E+) cattle are black and (E+/e) cattle are red. (E+/E+) cattle can be almost any color since other genes dictate which pigments are produced, such as the Agouti locus. 

BLACK: Breed standards call for a black-hided animal with a “reddish tinge.” Many animals found today are lacking in this trait and appear jet black with a “blueish tinqe,” which is more typical of Aberdeen Angus and & Welsh Black cattle.

The black allele is abbreviated ED (E for Extension, and the subscript D for dominant black). When mating a homozygous black (BB) animal to another all resulting offspring will be homozygous black (BB) carrying two copies of the dominant black allele for coat color, and are sometimes referred to as double black. 

Heterozygous black (Bb) carry a red allele and are sometimes referred to as red factor or red carrier. They carry one copy of the dominant black allele and one copy of the recessive red allele. This animal may be black or dun in color.

When mating heterozygous (Bb) x heterozygous black (Bb) results are 1BB, 2Bb, 1bb (25% chance homozygous black,  50% chance heterozygous black, 25% chance homozygous red).

If heterozygous (Bb) x homozygous red (bb) results are 2Bb, 2bb (50% chance heterozygous black, 50% chance homozygous red).

If heterozygous (Bb) x homozygous black (BB) results are 2BB, 2Bb (50% chance homozygous black, 50% chance heterozygous black).

RED: In the Belted Galloway breed red animals are found in several shades ranging from dark to light. A deep dark red coat with red pigment around the eyes and nose is commonly called a “cherry red.”  These animals are homozygous (e/e) for the recessive red allele. Lighter shades are the result of one or more modifier genes.

Reds can also be found in a gold/yellow variation resulting from one or more dilution gene(s). Dilution is considered dominant and a single dose will result in visible expression. Dilutions are the least understood genes in many breeds, yet have a very visible effect. 

The least common red in Belties is the “wild red” or Wild-type.

The red allele is abbreviated (e). A Beltie can only be homozygous red if it has two copies of the red allele (e/e), one from each parent.

When mating homozygous red (bb) x heterozygous black (Bb) results are 2Bb, 2bb (50% chance heterozygous black, 50% chance homozygous red).

If homozygous red (bb) x Homozygous red (bb) results are 4bb (100% chance of homozygous red).
If homozygous red (bb) x Homozygous black (BB) results are 4Bb (100% chance heterozygous black).

Golden Dun bull, Bolebec Dun Controller. 
Photographed Berryville, VA.

DUN: The second most common color of Belties is Dun (dn). The gene causing this coloration in Galloways and Belties is not yet known.  Dun animals have black noses. In Belties and Galloways homozygous dun (dn/dn) is dominant to black and animals show a more extensive reduction in pigmentation in both black and red coloration. A homozygous black Beltie (BB), but also homozygous for dun will appear silver. On the other hand, individuals homozygous for dun and also homozygous red (e/e) would appear very light red or even yellow.

Dun animals are found in chocolate, golden, and silver. I have always pondered the actual genetic makeup of “chocolate duns.” They just don’t seem to fit entirely into the dun category.  Could they contain some combination of wild-type, dilution, dun with Agouti influence?

WILD-TYPE: These are primitive colors found more commonly in solid color Galloways. Initial color coat testing done on wild type reds during the 1990’s by GenMARK concluded these animals were in fact heterozygous black (Bb). Today they are referred to as “Wild-type” or heterozygous red. Wild-type red animals have deep burgundy red bodies. The extremities (head, neck, feet) appear to be black from a distance.  When viewed up close or in natural sunlight the red coloration is visible down to the root.  Most appear to be Extension (E+) related.  Reports of Agouti (A+) influence have been reported in other breeds.

The wild-type allele is abbreviated (E+) A plus sign (+) always designates a wild-type allele. Wild-type alleles produce both eumelanin and phaeomelanin through intermediate amounts of tyrosinase. The ratio and distribution of these two pigments may be modified by other genes. The visible expression of eumelanin seems sex linked. As a rule wild-type (E+) bulls show a darker head, neck, feet than females.

Heterozygous black / wild-type carry one copy each of the dominant black allele and the wildtype allele (ED/E+). This combination of alleles will pass the wild-type allele to its offspring 50% of the time.  Calves have been born appearing red, gradually turning black with age. A reddish color at the hair shaft base and black along the remainder of the hair shaft have also been reported.

Heterozygous red / wild-type carry one copy each of the wild-type allele and recessive red allele (E+/ee). Variable coloration in these animals is expected and poorly documented. 

DILUTION in Belted Galloways and Galloways has not been well researched. TYRP1 is not the diluter gene of dun in Galloway and Highland. A diluter gene or genes (D) are suspected of causing Yellow or Pale Brown coat colors in various breeds.  Notations for dilution are: DD=dark, Dd=medium color, and dd= pale color. 

The identity of Diluter gene(s) is not known according to current documentation. As previously suggested by researchers it appears more than one diluter gene is at work. 

COLOR TESTING: DNA testing for MC1R (red vs. black) distinguishes heterozygous black cattle (Bb) who are red factor and those that are homozygous black (BB). Many labs also offer testing which can distinguish between the black (ED) allele, the red (e) allele, and the wild type (E+) allele. Some labs refer to “true black” or “true red” meaning they have found (ED/ED) and (e/e) with no (E+) present.

Definitions
ALLELES are alternate forms/varieties of a gene.
CARRIER is an individual heterozygous for a trait.
DILUTION GENE dilutes the expression of another gene in the phenotype.
DOMINANT ALLELES mask the presence of a recessive allele in the phenotype.
GENE POOL combined genes in all individuals in a breeding population.
GENES are units of inheritance.
GENOTYPE is the genetic makeup of an individual.
HETEROZYGOUS is a genotype consisting of two different alleles for a particular trait.
HOMOZYGOUS refers to a genotype consisting of two identical alleles for a particular trait.
MODIFYING GENE alters the expression of another gene in the phenotype.
PHENOTYPE is the visible traits of an individual.
RECESSIVE ALLELE is masked in the phenotype by a dominant allele.

References
Genetics of Coat Color in Cattle and Cattle Genome Committee Report February 1, 2002, Sheila M. Schmutz, Ph.D., U. of Saskatchewan, CAN.
Genetics of Colour Variation, T.A. Olsen, Animal Science Dept., University of FL.