Labs Offering Merle Testing
Results Offered and What Those Results Mean

Last updated Mar, 4, 2023

Note: Labs on this list who are using the term "cryptic Merle" are not referring to the proper genetic Mc allele on the M locus - 200 - 230 bp

Mc expresses and breeds the same as non-Merle.

These labs are still using the term in a general non-genetic manner which also includes "ghost", "hidden" and "phantom" Merle. In the past these terms have been used to describe a dog who was presumed to be m/m but then bred as a Merle - m/M.

These dogs may not be expressing a Merle pattern for several genetic reasons -
Ay - Clear Sable, e/e - Clear/Recessive Red/Yellow, Mosaicism or a shorter Non-Expressing Merle allele of Mc+ or Ma and occasionally Ma+.

The term cryptic Merle has also been used in the past to describe a "Minimal Merle" pattern which is known to be caused by two different Merle genotypes -
Mh - Harlequin Merle and Mosaicism where the longer original M allele has become the Minor allele.

Again this terminology was used in the past to describe something we had no genetic knowledge of. The newer method of high-resolution testing has given us theses answers.

"Cryptic Merle" now genetically refers to Mc - 200 - 230 bp, an allele on the M Locus that is so shortened/truncated that it can no longer express a Merle pattern..

Mc will express and breed the same as Non-Merle. Mc will not lengthen.

A dog who is m/Mc or Mc/Mc will not breed as M and will not produce offspring who are Merle patterned.

Also this article that can be downloaded and shared
"Defining Mc - Cryptic Merle

Labs offering High-Resolution Testing

Tilia - High-Resolution Testing Method - Recommended - Czech Republic 
https://www.tilialaboratories.cz/index.php?page=00101&lang=uk
Mc, Mc+, Ma, Ma+, M and Mh - base pair numbers provided. 
Mosaic results provided. 
Alleles based on the "langevin et al" paper.
Formerly Vemodia - lab that worked on the Merle paper with me.
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0198536

UC Davis - High-Resolution Testing Method - Recommended - California, USA
https://vgl.ucdavis.edu/test/merle
Base pair numbers provided.  Mosaic results provided.
After some comparison testing with UC Davis using dogs who have already been tested with Tilia the base pairs numbers from UC Davis seem to be a good comparison to the "langevin et al" scale.
NOTE - UC Davis' Mh allele starts at 268 bp.

NOTE - Although this lab is recommended for giving correct test results they unfortunately are still offering some outdated and erroneous information.

"Dogs with cryptic merle (also called phantom or ghost merle) typically display little to no merle pattern and some may be misclassified as non-merles."
The Mc allele as described by the "langevin et al" scale" - 200 - 230 bp - will NEVER display with any type of merle pattern or difference to coat shading and will always express the same as non-merle.

"Blue and partially blue eyes are typically seen with merle, and merle dogs may possess a wide range of auditory and ophthalmologic defects.
Only "Double Merle" combinations can cause vision and hearing impairments due to the deletion of pigment.

Dogs with two copies of any of the size variants consistent with merle (alleles other than N) are called double merles and often can have an all white coat accompanied by multiple abnormalities of skeletal, cardiac, and reproductive systems, therefore breeding two merle dogs is discouraged to avoid producing double merle offspring.
The only known and research verified impairments from a double merle combination are vision and hearing. There is no current reliable research showing double merle causes any other type of impairments. I cover this information in detail on this page https://merle-sine-insertion-from-mc-mh.webnode.page/myths-and-speculations/

"However, it is important to consider that many double merle dogs with ophthalmic and auditory defects often have a white spotting component and double merles in a breed with low piebald spotting allele frequency such as Catahoula leopard dogs, have fewer noted auditory and ophthalmologic defects.
 I honestly have no idea what this assumption is based on. S locus - Piebald (White Spotting) does not interact with M locus. As well any type of White Spotting (Piebald or Whitehead) is not known to cause any type of eye impairment, only hearing impairments. As a breeder of Catahoulas for 25 years I can attest to the fact that double merle combinations affect the breed the same as any other breed. UC Davis should understand that when making an erroneous claim such as this it should be backed by science and cited research.

EVG - Euro Vet Gene - High-Resolution Testing Method - Recommended - Slovenija 
https://www.eurovetgene.com/m-locus-merle
Mc, Mc+, Ma, Ma+, M and Mh - base pair numbers provided.
Mosaic results provided.
Alleles based on the "langevin et al" paper.
EVG's scale compares well with "langevin et al" scale. Their Mh starts at 269 bp.
Very pleased with their understanding of Merle and information they offer on-line.

InfogeneNZ - Massey University
High-Resolution Testing Method - Recommended - New Zealand
https://epagsc.myshopify.com/collections/frontpage/products/canine-testing
Mc, Mc+, Ma, Ma+, M and Mh - base pair numbers provided.
Mosaic results provided.
Infogene recommends a hair sample for testing. 
Alleles based on the "langevin et al" paper.
Several comparison tests already done show results to be a good comparison with the "langevin et al" scale.

Unistel Medical Laboratories - UML
High-Resolution Testing Method -Recommended - South Africa
https://unistelmedical.co.za/animal-genetics/dogs/
Mc, Mc+, Ma, Ma+, M and Mh - at this time I am not sure if base pair numbers are provided.
I will update with information once I have confirmation.
Mosaic results provided.
Alleles based on the "langevin et al" paper.
We do not yet have any tested examples  to know how their scale compares or where exactly their Mh allele starts.

Genomia
High-Resolution Testing Method - Recommended - Czech Republic 
https://www.genomia.cz/en/test/merle/
Genomia has recently updated their M locus testing and is now using the "langevin et al" scale.(Previously they were using the "Murphy et al" scale)
Mc, Mc+, Ma, Ma+, M and Mh - base pair numbers provided. Mosaic results provided.
We do not yet have any tested examples to know how their scale compares or where exactly their Mh allele starts.
Very pleased with their understanding of Merle (especially the Mc allele) and information they offer online.

Orivet - High-Resolution Testing Method 
Mc, Mc+, Ma, Ma+, M and Mh - base pair numbers provided.
Mosaic results provided.
Alleles based on the "langevin et al" paper.
After some comparison testing with Orivet using dogs who have already been tested with Tilia the base pairs numbers from Orivet are 3 - 4 bp shorter than the "langevin et al" scale.
Dogs tested as M are expressing an Mh phenotype and dogs testing on the high side of Ma+ express a typical M pattern. If you do have a result from Orivet it is important to add 3 - 4 bp to the number reported.
NOTE: Orivet seems to be having an issue reporting numerous visibly Merle dogs as m/m via swab sample. Offering information to owners that the dog must be a mosaic. 
This is incorrect information - a mosaic merle dog will not test as m/m.
The following chart shows 11 visible merle dogs tested as m/m with Orivet. This becomes a very big issue if the dog is NOT showing a visible merle pattern due to being "masked/hidden" or having a "non-expressing" allele.
Update March 2022 - No longer supplying base pair numbers with results - just the allele. Seeing as how 4 bp needs to be added to their results there is no way now to know the correct allele or how the dog will breed.

Laboklin/Labogen - High-Resolution Testing Method
Mc, Mc+, Ma, Ma+, M and Mh - UPDATE: Due to pressure from clients and competition from EVG, as of Sept, 2022 base pair numbers will be shared on results.
Mosaic results provided.
Suggests that Mc and Ma can lengthen to M 
"Cryptic Merle (Mc) is a short version of the merle allele with very little merling effect if any. Cryptic merle is not associated with health problems but it is a mutable allele and when the dog is bred it may well expand to regular merle in the puppies and so it should be treated same as regular merle and dogs with cryptic merle should only be bred to dogs with no merle." Same information is stated for the Ma allele.
This is of course incorrect - Mc will express and breed the same as Non-Merle. It will not lengthen.

Of great concern is the issue of them taking our chart and revising it without permission to include the combination of 
Mc/M as "low risk". Numerous attempts of requesting proof of any testing they have done that shows Mc/M deleting pigment to white have been in vain. Making this claim based on their own testing which they refuse to release examples of is extremely concerning and unprofessional. 
NOTE - comparison testing done shows they are starting their Mh allele at 270 when it should start at 269 bp.

Slovgen - High-Resolution Testing Method 
Using a revised scale of numbers set out in the "Murphy et al" paper - testing for T (poly-a tail) length.
Mc - cryptic merle - 25-62 T
Ma or Md - atypical or dilution - 63-73 T
M - merle - 74-85 TMh - harlequin - 86 and more T

These T numbers can be compared to base pairs by adding 187 to the number provided.
HOWEVER any comparison would have to be done using the "Langevin et al" scale.

Mc going all the way to 249 is much too long. There is a very good chance that a length of 62T (249 bp) will delete pigment to white when combined with M. 249 bp is the Ma allele.
Mc should not go past 43T (230bp) in order to ensure that no pigment is deleted to white when combined with M. Their M allele is starting at 261 bp which is still very much Ma+ and not a typical M allele.
If you do have a result from Slovgen add 187 to the T length to get the base pair numbers and use the "Langevin et al" scale to identify the correct allele. 

Stated on their website - "The dog can be merle mosaic, ie. It can carry several types of merle alleles in its cells. Intergenerationally, it may lead to shortening or expansion of the merle allele. In general, it is not appropriate to mate dogs with merle alleles together because of potential health risks"
This is not correct - Mc has never shown to lengthen to any other allele and is very safe at a length of 43T - (230 bp) to breed to M. I have only seen a few results from Slovgen so am not sure if they are providing mosaic results or just mention it on their website.

ZooOmics  - High-Resolution Testing Method
Using a revised scale of numbers set out in the "Murphy et al" paper - testing for T (poly-a tail) length.
(See explanation given above for Slovgen.)
Based pair numbers are not provided.

Feragen - High-Resolution Testing Method

Mc, Ma, M and Mh - base pair numbers provided.
Mosaic results provided. 

Still using outdated Cryptic Merle information.
"Cryptic merle dogs (Mc) or called phantom merle show no changes in coat color or only very small inconspicuous areas on the body can indicate merle."

Tilia, UC Davis, InfogeneNZ - Massey, Euro Vet Gene, Unistel and Genomia
are the labs I recommend from this list.

"Cryptic -Most cases are non-merle but in rare cases may have very small merle patch(es) or subtle color anomalies"

Differences between "langevin et al" Mc and Mc+ alleles -
Mc when bred to M does not delete pigment to white.

Mc+ when bred to M does have the ability to delete pigment to white and therefore comes with the risk of hearing and/or vision impairments as the following example demonstrates.

Suggests that Mc can lengthen and Mc should not be bred to M due to the chance for "Double Merle" offspring.
Any dog testing as m/Mc that produces Merle pattern offspring will have an M allele, it is a matter of finding it with further investigation. Mc has not lengthened to M
Ben was tested as m/Mc but produces Merle patterned offspring. I arranged for further testing with Tilia labs using a Germline cell sample (semen) and of course there was a minor M allele. Mc does not lengthen to M. 

Paw Print does report base pair numbers and mosaic results (as well as the percentage present in the sample material of each allele which I really like) and even though their Mc allele is much too long, the "langevin et al" scale can be used as a comparison to find the exact allele and how a dog will breed. However I cannot recommend a lab that has no understanding of the genetics of Minimal Merle and the Mc - Cryptic Merle allele and has advised clients that Mc can lengthen to M and therefore should not be bred to M because of the risk of M/M offspring.
I know many breeders who have removed Mc dogs from breeding programs due to this very incorrect advice from PPG.

Labs using Old Testing Method

Embark - Old Testing Method - Recommended 
M* - SINE insertion "yes" or "no"
Offers a very in-depth description of what the results mean and where further testing can be done based on the "langevin et al" paper.
https://embarkvet.com/resources/blog/embark-introduces-merle-coat-color-testing/

GenSol - Old Testing Method - Recommended 
M - SINE insertion "yes" or "no".
Offers an explanation of the lengths of Merle and suggestions further more detailed testing.
https://www.gensoldx.com/product/m-locus-merle/

Animal Genetics - Old Testing Method  

Mc, Ma and M - does not provide base pair numbers.

Using outdated non-genetic information for the meaning of "cryptic merle".
"Many solid dogs are actually cryptic or phantom merles and can produce both Merle and double merles. A cryptic or phantom Merle is a dog which phenotypically appears to be a non-merle or very faint patches of Merle that can go unnoticed. Animals that do not present the Merle phenotype may possess the Merle genotype and subsequently produce Merle offspring. These animals are known as cryptic Merles."
This does not refer to the known genetic Mc - Cryptic Merle allele - note the use of the word "phantom."

Antagene - Old Testing Method
M - SINE insertion "yes" or "no"

Certegen - Old Testing Method 
 Mc and M
"Dogs with cryptic merle (also called phantom or ghost merle), typically display little to no merling and some may be misclassified as non-merles."
Using outdated non-genetic information for the meaning of "cryptic merle". 

Pet Genetics Lab - Old Testing Method
M - SINE insertion "yes" or "no"
"Recent research has shown that the prevalence of deafness in Merle dogs is 54.6% in double merles and 36.8% in single merles. "
No idea where they got these stats from. m/M does not cause any hearing and/or vision impairments.
"A dog who has one copy of the insertion can also show very little Merle colouring and is described as a cryptic merle."
Using outdated non-genetic information for the meaning of "cryptic merle". 

Wisdom Panel/Optimal Selection - Old Testing Method

Mc and M

MYDOGDNA -Old Testing Method 
M - SINE insertion "yes" or "no".

"It is now known that there are varying lengths to the insertion, enabling subclassification of different merle alleles. In general, a "cryptic merle allele" (Mc) is a merle insertion shortened to the extent that it is no longer able to cause a coat pattern change even when it is present in the genome of a dog. Therefore, dogs carrying "cryptic merle" show only very slight merle colouration or no merle colouration at all. The cryptic merle allele is currently not known to be associated with health concerns. The merle test included in the MYDOGDNA™ testing service is able to state whether a SILV gene merle-associated insertion is present in the genome of the tested dog, but does currently not report separately on different lengths of the insertion."

They do provide the information that there are different merle alleles and they only test for the presence or absence of the SINE insertion, however there is no understanding of the Mc - Cryptic Merle allele which will never "show only very slight merle colouration." 

"Dogs that carry two copies of (= are homozygous for) the merle (M/M) variant are usually predominantly white. These so called double merle dogs (M/M) are prone to several health concerns, such as deafness, eye development defects and blindness, and may be stillborn. In certain breeds, also heterozygous merle (M/m) dogs may suffer from similar health issues. Mating of two merle is not recommended to avoid the health concerns associated with double merle dogs."

The only known issues from "Double Merle" are vision and/or vision impairments. It does not cause a pup to be "stillborn".
It is not correct that "in certain breed, m/M dogs may suffer similar health issue."
I go over these incorrect ideas in detail on the "Myths and Speculations" page.

Embark and GenSol are the labs I recommend from this list.