$75.00 (RRP)



Orivet, a leader in innovative animal health, provides over 260 Tests for Dog Breeders including Single Assays - health and phenotype.

Merle, dapple the M Locus coat colour test to determines the allele size of the mutation.  Our test can detect the various patterns M (classic Merle), Mc (cryptic), Ma (atypical) Mh (harlequin) and m (non-merle).  These various types allow you determine the effect on coat colour and health status. Please see more in Test Overview below. 

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Please Note: Orivet results are on average 2 to 3 base pairs lower than reported previously (Langevin et al; 2018).  This may result in some Merle classification differences between laboratories. 
Orivet has a sublicense granted by IDEXX Laboratories Inc.  In some cases you may need to include a hair sample with ALL swab samples submitted.  Click here to download our Merle Hair Sample Submission Form.
Click here for a Merle Fact Sheet.

Test Overview:

Please Note - Orivet results are on average 2 to 3 base pairs lower than reported previously (Langevin et al; 2018). This may result in some Merle classification differences between laboratories. Merle dog coat color is a coat pattern in domestic dogs, specific for patches of diluted pigment mixed together with normal melanin. Dog homozygous for merle gene is known as double merle (genotype MM). Double merle has been recognized as sublethal and is associated with many abnormalities in the reproductive, cardiac and skeletal system. Many of these abnormalities share similarities with Waardenburg syndrome (WS), an autosomal dominant auditory-pigmentation disorder in humans.


Trait (Associated with Phenotype)



Variant Detected:

250 base pair SINE insertion, oligo(dA)-rich tails with length polymorphism. Detects and reports all the 7 alleles on the M Locus (Mh, M, Ma+, Ma, Mc+, Mc and m)


It is a trait and so is tested based on preference, not usually for health concerns.

Mode of Inheritance:

Dominant with Variable Expressivity

Research Citation(s):

Langevin et al; PLoS One. 2018; 13(9): Merle phenotypes in dogs – SILV SINE insertions from Mc to Mh.
Leigh Anne Clark, Jacquelyn M. Wahl, Christine A. Rees, and Keith E. Murphy (2006): Retrotransposon insertion in SILV is responsible for merle patterning of the domestic dog. PNAS 103 (5) 1376-1381, 2006,doi:10.1073/pnas.0506940103
Hedan, B. et al. (2006.): Coat color in dogs: identification of the Merle locus in the Australian shepherd breed. BCM Vet Res. 2:9.
Strain et al. (2009.): Prevalence of Deafness in Dogs Heterozygous or Homozygous for the Merle Allele. J Vet Intern Med 2009; 23:282-286.
Langevin M, SynkovaH, Jancuskova T, Pekova S (2018) Merle phenotypes in dogs – SILV SINE insertions from Mc to Mh. PLoS ONE 13(9): e0198536. pone.0198536

Associated Breed(s):

American Bulldog , American Bully , American Cocker Spaniel, American Staffordshire Terrier, Aussiedoodle, Australasian Bosdog, Australian Bulldog, Australian Cobberdog, Australian Kelpie, Australian Labradoodle , Australian Shepherd, Bernedoodle, Border Collie, Bordoodle, British Bulldog, Cardigan Welsh Corgi, Catahoula, Catahoula Leopard Dog, Cavalier King Charles Spaniel, Chihuahua, Cockapoo, Cocker Spaniel, Collie Rough, Collie Smooth, Colonial Cocker Spaniel, Dachshund , Dachshund Short Hair, Dachshund Standard Long Hair, Dachshund Standard Smooth Hair, Dachshund Standard Wire Hair, Dachshund Wire Hair, French Bulldog, Goldador, Golden Retriever, Goldendoodle, Great Dane, Koolie , Miniature American Shepherd, Miniature Australian Shepherd, Miniature Dachshund, Miniature Dachshund Long Hair, Miniature Dachshund Short Hair, Miniature Dachshund Smooth Hair, Miniature Dachshund Wire Hair, Miniature Poodle, Miniature Schnauzer, Moodle, Moyen Poodle, Mudi, Old English Sheepdog , Papillon, Pyrenean Sheepdog, Sheepadoodle, Shetland Sheepdog, Smithfield, Southern Cross Bulldog, Spoodle, Standard Poodle, Toy Poodle,