UC Davis School of Veterinary Medicine Veterinary Genetics Laboratory

Dog Coat Color Dilute(Blue)

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A recessive mutation in the melanophilin (MLPH) gene was identified as the cause of color dilution phenotypes in the dog. Two alleles (variants) are described: the dominant full color (D) and the recessive dilute (d). Two copies of dilute are needed to lighten black pigment to grey (often called blue) and red pigment to cream (also called buff). A diagnostic DNA test identifies the specific variants of the MLPH gene.

NOTE: Another as yet unidentified mutation causing color dilution is known to occur in some breeds such as Doberman Pinscher, French Bulldog, Italian Greyhound, Chow Chow and Shar-Pei. In these breeds, and likely others as well, some dogs may carry both the known and unknown dilution mutations and present a dilute phenotype.

Results from the DILUTE test are reported as:

D/D Full color, no dilute gene present

D/d Full color, carries 1 copy of the dilute gene

d/d Dilute, 2 copies of the dilute gene


Drögemüller C, U. Philipp, B. Haase, A-R Günzel-Apel & T Leeb. A noncoding melanophilin gene (MLPH) SNP at the splice donor of exon 1 represents a candidate causal mutation for coat color dilution in dogs. Journal of Heredity 98(5):468-473 (2007).

Veterinary Genetics Laboratory, Tel 530-752-2211, Email VGL