Trait overview

Merle coat coloring is described as irregular dilutions of color throughout the coat. There are four main groups of merle coloring, they are cryptic, atypical, classic, and harlequin. Cryptic merle does not change the original coat color of the dog but will test positive for the mutation. atypical merle results in a slight merle patterning of the coat, whereas classic merle is the typical spotting pattern than is generally associated with merle coats. Lastly, harlequin merle is characterized by stronger dilutions of color, in these cases it is possible to see mostly white coloring due to the amount of color dilution.

Gene name(s)

PMEL

Inheritance

Autosomal incomplete dominance

More common in the following breeds

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Citations

Clark LA, Wahl JM, Rees CA, Murphy KE. Retrotransposon insertion in SILV is responsible for merle patterning of the domestic dog. Proc Natl Acad Sci U S A. 2006 Jan 31;103(5):1376-81. doi: 10.1073/pnas.0506940103. Epub 2006 Jan 9. PMID: 16407134; PMCID: PMC1360527.

Brancalion L, Haase B, Wade CM. Canine coat pigmentation genetics: a review. Anim Genet. 2022 Feb;53(1):3-34. doi: 10.1111/age.13154. Epub 2021 Nov 9. Erratum in: Anim Genet. 2022 Jun;53(3):474-475. PMID: 34751460.