Dogs display a wide variety of coat colours and patterns. Classification of these colours can be confusing sometimes because different registries or associations may use different names for the same colour. In each dog two pigments are the basis for their coat colour: black pigment (eumelanin) and red/yellow/cream pigment (pheomelanin). The production of black and red/yellow/cream pigment is controlled by the Melanocortin 1 Receptor (MC1R) gene, also known as Extension gene or E-Locus. Several other genes are involved that modify the black and red/yellow/cream pigment resulting in a variety of colours and patterns found in the domestic dog. The Tyrosinase-Related Protein 1 (TYRP1) gene, also known as Brown gene or B-Locus dilutes black pigment to brown but does not have an effect on red/yellow/cream pigment. Another gene involved in the coat colour of dogs is the Agouti (ASIP), also known as A-Locus, which controls the distribution of black and red/yellow/cream pigment. The Dilute (MLPH) gene, also known as D-Locus dilutes the black and red/yellow/cream pigment. The Beta-defensin (CBD-103), also known as K-Locus is unique to dogs and is responsible for dominant black. Some other genes that add white patterns and dilute colours are also present but are specific to certain breeds.
Within the above described coat colour genes, three genes explain the major differences; the E-, B-, and D-Locus genes. In the table below the possible combinations of the genes are indicated.
| E-Locus | B-Locus | D-Locus | Coat colour | Nose / foot pads |
|---|---|---|---|---|
| e/e | B/B | D/D or D/d | Red/Yellow/Cream* | Black |
| e/e | B/B | d/d | Champagne* | Blue to Black |
| e/e | B/b | D/D or D/d | Red/Yellow/Cream
(carrier Black/Brown/Chocolate/Liver)** |
Black |
| e/e | B/b | d/d | Champagne
(carrier Black/Brown/Chocolate/Liver)** |
Blue to Black |
| e/e | b/b | D/D or D/d | Red/Yellow/Cream ** | Pink to Brown |
| e/e | b/b | d/d | Champagne** | Pink to Brown |
| E/e | B/B | D/D or D/d | Black, no mask (melanistic mask)
(carrier Red/Yellow/Cream) |
Black |
| E/e | B/B | d/d | Blue/Grey/Charcoal, no mask (melanistic mask)
(carrier Red/Yellow/Cream) |
Blue to Black |
| E/e | B/b | D/D or D/d | Black, no mask (melanistic mask)
(carrier Red/Yellow/Cream) (carrier Black/Brown/Chocolate/Liver) |
Black |
| E/e | B/b | d/d | Blue/Grey/Charcoal, no mask (melanistic mask)
(carrier Red/Yellow/Cream) (carrier Black/Brown/Chocolate/Liver) |
Blue to Black |
| E/e | b/b | D/D or D/d | Brown/chocolate/liver, no mask (melanistic mask)
(carrier Red/Yellow/Cream) |
Pink to Brown |
| E/e | b/b | d/d | Lilac/Isabella, no mask (melanistic mask)
(carrier Red/Yellow/Cream) |
Pink to Brown |
| Em/e | B/B | D/D or D/d | Black, mask (melanistic mask) is not visible
(carrier Red/Yellow/Cream) |
Black |
| Em/e | B/B | d/d | Blue/Grey/Charcoal, mask (melanistic mask) is not visible
(carrier Red/Yellow/Cream) |
Blue to Black |
| Em/e | B/b | D/D or D/d | Black, mask (melanistic mask) is not visible
(carrier Red/Yellow/Cream) (carrier Black/Brown/Chocolate/Liver) |
Black |
| Em/e | B/b | d/d | Blue/Grey/Charcoal, mask (melanistic mask) is not visible (carrier Red/Yellow/Cream)
(carrier Black/Brown/Chocolate/Liver) |
Blue to Black |
| Em/e | b/b | D/D or D/d | Brown/Chocolate/Liver, with mask (melanistic mask)
(carrier Red/Yellow/Cream) |
Pink to Brown |
| Em/e | b/b | d/d | Lilac/Isabella, with mask (melanistic mask)
(carrier Red/Yellow/Cream) |
Pink to Brown |
| E/E | B/B | D/D or D/d | Black, no mask (melanistic mask) | Black |
| E/E | B/B | d/d | Blue/Grey/Charcoal, no mask (melanistic mask) | Blue to Black |
| E/E | B/b | D/D or D/d | Black, no mask (melanistic mask)
(carrier Black/Brown/Chocolate/Liver) |
Black |
| E/E | B/b | d/d | Blue/Grey/Charcoal, no mask (melanistic mask)
(carrier Black/Brown/Chocolate/Liver) |
Blue to Black |
| E/E | b/b | D/D or D/d | Brown/Chocolate/Liver, no mask (melanistic mask) | Pink to Brown |
| E/E | b/b | d/d | Lilac/Isabella, no mask (melanistic mask) | Pink to Brown |
| Em/E | B/B | D/D or D/d | Black, mask (melanistic mask) is not visible | Black |
| Em/E | B/B | d/d | Blue/Grey/Charcoal, mask (melanistic mask) is not visible | Blue to Black |
| Em/E | B/b | D/D or D/d | Black, mask (melanistic mask) is not visible
(carrier Black/Brown/Chocolate/Liver) |
Black |
| Em/E | B/b | d/d | Blue/Grey/Charcoal, mask (melanistic mask) is not visible
(carrier Black/Brown/Chocolate/Liver) |
Blue to Black |
| Em/E | b/b | D/D or D/d | Brown/Chocolate/Liver, with mask (melanistic mask) | Pink to Brown |
| Em/E | b/b | d/d | Lilac/Isabella, with mask (melanistic mask) | Pink to Brown |
| Em/Em | B/B | D/D or D/d | Black, mask (melanistic mask) is not visible | Black |
| Em/Em | B/B | d/d | Blue/Grey/Charcoal, mask (melanistic mask) is not visible | Blue to Black |
| Em/Em | B/b | D/D or D/d | Black, mask (melanistic mask) is not visible
(carrier Black/Brown/Chocolate/Liver) |
Black |
| Em/Em | B/b | d/d | Blue/Grey/Charcoal, mask (melanistic mask) is not visible
(carrier Black/Brown/Chocolate/Liver) |
Blue to Black |
| Em/Em | b/b | D/D or D/d | Brown/chocolate/liver, with mask (melanistic mask) | Pink to Brown |
| Em/Em | b/b | d/d | Lilac/Isabella, with mask (melanistic mask) | Pink to Brown |
* Note: This dog can still have Black/Blue/Grey/Charcoal puppies
** Note: This dog can still have Black/Blue/Grey/Charcoal puppies or Brown/Chocolat/Liver/Lilac or Brown/Chocolate/Liver/Lilac/Isabella puppies
