Occasionally a Kelpie with a paler coat colour may be found. It may be grey, like the lead tip of a pencil, or a more wheat coloured coat. These dogs are called smoke blue, or fawn, with a washed out or diluted version of black and brown. A gene is involved that affects the intensity of eumelanin in the coat, nose and eyes, which dilutes black to a darker grey and brown to hues of grey and beige.
Dilution is a recessive gene, which means that both parents must carry this gene for their offspring to be smoke blue or fawn. Two brown parents with dilution heritage can only leave offspring which are brown or diluted brown (fawn), and of course the basic colours black and brown.
As with the brown dogs, different hues of smoke blue or fawn may exist and that is why these two colours sometimes get mixed up. One way to determine the colour of a Kelpie is to look at the nose. A smoke blue dog has a steel grey nose, and a fawn dog has a nose which is coloured towards brown or lilac.
The genotype for the dominant form is D
and this Kelpie will be black or chocolate/red. The recessive form for this gene is d/d and this Kelpie will be smoke blue or fawn.
The alleles in the D series of the Kelpie:
D = normal pigment
d = diluted pigment