A Parti coloured dog has a coat that is at least 50% white with patches of any solid colour.

 

S locus alleles (or MITF gene) determine the degree and distribution of spotting. Parti dogs have a MITF gene that causes large patches with no colour.

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A tri-coloured pup is a parti (black & white or chocolate & white) dog that also has tan coloured phantom markings on the eyebrows, muzzle, lower legs and beneath the tail.