Two pigments make every colour
For all the variety you see in the breed, every Border Collie colour is built from just two pigments. Eumelanin is the black‑based pigment; phaeomelanin is the red‑based pigment. Genes never invent new colours — they only modify, dilute, mask or restrict these two across the coat.
Eumelanin defaults to black, but other genes can turn it to chocolate, slate‑blue or lilac. Phaeomelanin ranges from a pale biscuit through gold to a deep ginger. Where each pigment lands on the body — and how strong it is — is decided at a handful of genetic locations called loci.
The colour loci at a glance
A locus is a place on a chromosome where a colour gene lives, and a dog carries two copies of each — one from each parent. The main loci covered on this site are:
Dominant and recessive
For most colour genes, one copy of a dominant allele is enough to show its effect; a recessive colour only appears when the dog inherits two recessive copies. A black dog, for instance, can quietly carry chocolate, dilute and ee red without showing any of them — and pass them on. That is why two black‑and‑white parents can surprise you with a chocolate, blue or red puppy.
Read the nose first
When a coat looks washed‑out or ambiguous, the nose, eye rims and lips usually tell the truth. Their colour reveals the dog's underlying genetic colour even when the coat is masked or diluted. The Nose & Eye Colour page explains how to read them.
Ready to explore? Pick any colour or pattern from the menu above, or start with the breed's default coat — black.
