Coat Colours and Patterns

S-Locus (Piebald)

S-Locus (Piebald, White Spotting) Piebald is a coat pattern characterized by the presence of white spots or splotches on the fur. This pattern is caused by a mutation in the gene encoding -associated transcription factor (MITF), commonly referred to as the Spotting Locus (S-Locus). Piebald is a form of white...

Coat Colour Introduction Dogs

Introduction to coat colours in dogs In dogs, coat colour is a complex trait influenced by a variety of genes interacting with each other. Mutations in these genes (or loci*) can interact in intricate ways, leading to the diverse range of coat colours and patterns seen in modern dog breeds....

Co-Locus Dog (Cocoa)

Co-Locus Dog (Cocoa) Chocolate or brown coat colour is fairly common in dogs. The most well know variant is the B-locus on the tyrosinase related protein 1 (TYRP1) gene. The mutations in TYRP1 gene are responsible for the dilution from black to brown. However, more recently (2020) it has been...

E-Locus Dog

E-Locus Coat colour in dogs is controlled by a wide range of different genes working together. These genes are often referred to as ‘loci’. The Extension, or E-Locus, corresponds to the gene ‘melanocortin 1 receptor’ (MC1R), which is involved in the regulation of pigment production. Active MC1R causes a cell...

B-Locus Dog (Brown)

B-Locus Dog (Brown) Coat colour in dogs is regulated by a complex interplay of various genes, often known as 'loci.' The Brown locus, or B-Locus, is associated with the tyrosinase-related protein 1 gene (TYRP1), which governs the synthesis of eumelanin, the black pigment (E-locus). Multiple mutations on the B-Locus lead...

D-Locus Dog (Dilution)

D-Locus (Dilution) The Dilution, or D-Locus, corresponds to the gene for melanophilin, MLPH, which is involved in the distribution of pigment. Mutations of the D-Locus result in a ‘dilution’ that affects the eumelanin (black) and phaeomelanin (red/yellow) pigments in the coat. Affected dogs have a diluted or lighter coat coloration...

I-Locus Dog (Intensity)

I-Locus (Intensity) The Intensity-locus (I-Locus) in dogs is linked to the gene encoding the Major Facilitator Superfamily domain-containing protein 12 (MFS12), which plays a role in phaeomelanin production (light pigment). In dogs with the wild-type genotype, hair expressing only phaeomelanin displays as a red, gold, or tan coat. Conversely, a...

A-Locus

The Agouti gene (ASIP gene) is responsible for the production of a protein that regulates the distribution of black pigment (eumelanin) within the hair shaft. This gene is also known as the A-locus and determines whether an animal expresses an agouti appearance, and if so what type, by controlling the...

K-Locus Dog (Dominant Black)

K-Locus (Dominant Black) The K-Locus (also known as the Dominant Black Locus) is one of the most fundamental factors in the development of a dog's coat colour. The K-Locus corresponds to the gene Beta-defensin 103 (CBD103). This gene affects pigment switching between eumelanin (black) and phaeomelanin (red or yellow) by...

M-Locus (Merle) and H-Locus (Harlequin) Dog

M-Locus (Merle) and H-Locus (Harlequin) Merle pattern in dogs The merle coat pattern in dogs is caused by a mutation in the PMEL17 gene involving a SINE insertion. This mutation affects eumelanin (dark pigment) but does not impact the production of pheomelanin (red pigment). Dogs with the e/e genotype at the...

Saddle tan vs black-and-tan

The hnRNP associated with lethal yellow gene (RALY gene) defines whether tan points or saddle tan is expressed in Basset Hounds and Pembroke Welsh Corgi dogs. Black and tan colour is characterized by light colour on the muzzle, above the eyes (tan points) and on the undersides of the dog...

Panda White Spotting Dog

Panda White Spotting White spotting in many animals is typically caused by a mutation to the tyrosine kinase receptor (KIT) gene. KIT plays a broad role in an animal's development and helps govern the formation of pigment-containing cells. In dogs there are several examples where a KIT mutation has been...

Albinism Dog

Albinism Most genetically-determined coat colour traits are caused by various genes (mutated or otherwise) affecting the amount and distribution of melanin (pigment) in an animal's hairs and skin. Albinism, however, involves a general loss of pigment production. The traits described in this section are all forms of Oculocutaneous Albinism (OCA),...

Roan-Ticked Dog

Roan-Ticked The Ticking, or T-Locus, corresponds to the usherin gene (USH2A), which helps control the development of the dog’s coat pattern. T-Locus mutations in dogs cause the development of alternating areas of white and pigmented hairs, which can result in two distinct patterns: Ticked and Roan. A Ticked coat features...

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