Merle and Brindle
Merle or brindle patterns are not allowable and are to be disqualified. -SHCA Siberian Husky Standard
Merle is a color that displays irregularly-shaped patches with less black/brown pigment. The mutation interferes with eumelanin deposition in some pigment cells resulting in patches of cells that have less black pigment and a marbled or mottled appearance. On a domino Siberian that already has a lot of lighter colored undercoat, the black tipping can appear blotchy with normal eumelanin shading in some areas and variable patches of less shading in others. This color may be associated with a wide range of auditory and ophthalmologic abnormalities especially in the homozygote. This allele is not found in Siberians and therefore its presence indicates gene flow from another breed.
Brindle arose by a rearrangement between Kb and ky chromosomes in a black dog, leading to a duplication of the defensin cluster at least 1000 years ago. Brindle has both ky and Kb alleles on the same chromosome, so they test Kb/ky but they have at least 3 copies of this gene. One copy is randomly silenced in different pigment cells, which leads to a variegated red and black pattern depending on whether Kb or ky was silenced. Like Merle, Brindle is not found in the Siberian breed. Thus, the presence of this color indicates gene flow from another breed.