Pigment follows the colour genes
The nose leather, eye rims, lips and even the iris take their colour from the same genes that colour the coat — chiefly the B locus and the D locus. That is why pigment is the most reliable way to read a dog’s true genetic colour, especially when the coat is masked or diluted.
The B series and eye colour
The B series only affects eumelanin. B/B or B/b allows black pigment; b/b makes brown pigment wherever the dog would otherwise be black.
- Black dogs — eye colour ranges from yellowish through to dark brown.
- Brown (chocolate) dogs — a brown nose (from b/b D/_) and an eye that runs greenish, amber, orange or brown.
- Lilac dogs — with b/b d/d, the nose is a rosey‑grey and the eye is lighter still.
The D series and eye colour
The D, or dilution, series also softens pigment. D allows full pigment; d/d dilutes both eumelanin and phaeomelanin by clumping the pigment granules. A dilute‑black dog (B/_ d/d — blue or slate) wears a grey nose instead of black, and eye colour ranges from very pale to a light brown.
ee red pigment
On an ee red dog the eye and nose depend on what is at the B and D loci underneath the mask. If the masked colour is brown, the nose is brown; if it is black, the nose is black; eyes can run from very pale to brown.
Merle: china eyes & marbling
A merle can be any colour, so its nose, lips and eye pigment match its true colour — the darkest colour on the dog, plus the pigment, tells you what it really is. Merles often have patches of pink on the nose. Their eyes may be sky blue (also called china eyes) or marbled — slices, spots or several colours in one eye. Sky‑blue eyes are simply another colour: they are not blind, contrary to a common myth.
White, pigment & deafness
High amounts of white on the head can be troublesome, especially when both eyes are sky blue with no pigment over the ears — that combination is associated with deafness. Dogs with well‑pigmented noses, pigmented eyes and colour over the ears are far more likely to have normal hearing, though any dog can be deaf in one or both ears. Before breeding, have eyes CERF‑certified, DNA test for CEA, and use the BAER test to confirm hearing.
