In some breeds, such as Labrador Retrievers the dogs are more yellow than red. The shade varies as is illustrated by the two littermates above whose parents were also both yellow. Both pups have black nose leather, irrelevant of their shade of yellow. This is because both are B/B at the TYRP1 gene. Labrador Retreivers with a b/b genotype have brown noses.

Little did not include the Hungarian Vizsla in his studies. They are hunting dogs which are typically gold to red and typically have brown noses because they are also homozygous for the recessive brown allele/s at the B locus. (see Brown for further details)

There is a DNA test that reliably detects the b alleles in all breeds studied.

Some dogs have a mutation or mutations in the MLPH gene or D locus that causes their black hair to become gray. This same d/d genotype also dilutes the color of their nose leather, eye rims, and paw pads. Shady is an example of a fawn Shar-Pei with a gray mask, instead of black, and the matching gray nose leather, etc.

Although there are DNA tests that detect the d allele or alleles in some breeds, the reliability in "all" breeds seems doubtful.

In several breeds with piebald or random white spotting, the pups are born with pink areas on the nose leather and pads. Pigmentation migrates to these areas late. In most dogs, the nose leather fills in with pigment - black, brown, gray. However, in some dogs the pigmentation does not completely fill in by adulthood and they retain a small pink spot on their nose for life. The Large Munsterlander shown at the right is about 6 months old.

Although a DNA test to detect the s^p allele is available that works in many breeds, this test does not predict if there will be lasting pink spots on the nose - just that there will be lasting areas of white, roan or ticking on the coat.

The term "snow nose" or "winter nose" is used for the seasonal change in nose pigmentation that occurs in some dogs. The middle of the nose looses color and becomes pinkish, as shown on the Saluki at the left at the end of winter. The outer edges usually remain the original color. The color does return to this Saluki, as shown on the right, in summer. Some owners have observed that over the years the color does not totally come back during the summer months as the dog ages.

The biochemical cause of this phenomenon is not understood. No gene causing this seasonal change in nose color has been reported. It is not even clear if this runs in families or not.

Note that the paw pad pigmentation is not lost, as the same Saluki demonstrates on the far right.

In some breeds, dogs are born with pink noses and these remain pink throughout life. Easy is a Chinese Shar-Pei with a pink nose, eye rims and pads. Easy has an e/e genotype at MC1R, but the additional interacting gene that causes the pink nose has not yet been determined.