Testing Before Breeding: Available Tests and Labs

When I started breeding in the 1980s, genetic testing for dogs was essentially non-existent. We made decisions based on phenotype, pedigree analysis, and the accumulated wisdom of experienced breeders. Some of that wisdom was sound. Some of it was wishful thinking that cost puppies their health. Today, we have no excuse for guesswork.

Modern genetic testing can tell you exactly what merle alleles your dog carries with virtually perfect accuracy. The tests are affordable, widely available, and simple to administer. Every breeder working with merle-affected breeds should understand what tests exist, how to interpret the results, and which laboratories provide reliable service.

Understanding Merle Testing

Merle genetic tests work by measuring the length of the SINE insertion in the PMEL17 gene. This is not a simple yes/no test - the results include the specific length of the insertion in base pairs, which determines which merle allele the dog carries.

What the results tell you:

Result	Base Pairs	Meaning
m/m	N/A	Non-merle - no SINE insertion
Mc/m	200-214	Cryptic merle - invisible carrier
Mc+/m	215-229	Cryptic+ merle - may show minimal merling
Ma/m	230-249	Atypical merle - variable expression
Ma+/m	250-264	Atypical+ merle - usually visible
M/m	265-268	Classic merle - standard pattern

The critical point is this: any dog carrying any merle allele, regardless of length, should not be bred to another merle carrier without careful consideration. Even cryptic-to-cryptic breeding can produce puppies with longer merle alleles due to the instability of SINE insertions.

Recommended Testing Laboratories

Not all laboratories offer the detailed allele-length reporting that responsible breeders require. Some older tests simply report "merle positive" or "merle negative" without specifying the allele type. This is insufficient for making informed breeding decisions. I recommend using laboratories that provide full fragment length analysis.

United Kingdom

• Animal Genetics UK - Comprehensive merle panel with full allele reporting
• Laboklin UK - German laboratory with UK sample collection
• The Kennel Club DNA Testing - Partners with various labs for breed-specific panels

United States

• Embark Veterinary - Detailed merle allele reporting included in comprehensive panel
• Animal Genetics - Specific merle testing with fragment length
• UC Davis Veterinary Genetics Laboratory - Research-grade testing
• Paw Print Genetics - Full merle panel with clear result reporting

Europe

• Laboklin (Germany) - Excellent reputation for accuracy
• Antagene (France) - Comprehensive canine genetics panel
• ScreenFido (Netherlands) - Specialized in colour genetics

Responsible breeders like Amandine Aubert at Bloodreina demonstrate that color genetics can be managed safely through comprehensive DNA testing. She routinely uses Antagene and Laboklin for full merle allele-length reporting on every dog in her programme, a standard of diligence that newer breeders would do well to emulate.

The Testing Process

Merle DNA testing is straightforward and non-invasive. Most laboratories accept cheek swabs, which you can collect at home following the kit instructions. Some also accept blood samples collected by a veterinarian, which may be combined with other health testing.

Step-by-Step Collection

1. Order the test kit from your chosen laboratory
2. Do not allow the dog to eat or drink for 1-2 hours before collection
3. Use the provided swabs to rub firmly against the inside of the cheek
4. Rotate the swab to collect cells from the cheek lining
5. Air dry the swabs as directed (usually 5-10 minutes)
6. Package and return in the provided materials

Results typically arrive within 2-4 weeks, depending on the laboratory and postal services. Some laboratories offer expedited processing for an additional fee.

Interpreting Your Results

Understanding your test results is essential for making safe breeding decisions. Here is how to interpret the most common scenarios:

Non-Merle (m/m)

The dog carries no merle alleles. It can be safely bred to any merle without producing double merles. However, approximately half the offspring from such a pairing will be merle carriers.

Single Merle Carrier (M/m, Ma/m, etc.)

The dog carries one merle allele. Safe breeding options include:

• To a confirmed non-merle (m/m) - No double merle risk
• Never to another merle carrier of any type

Double Merle (M/M, Ma/M, etc.)

The dog carries two merle alleles. All offspring will be merle carriers. Double merles should generally not be bred, both because of their own health complications and because all puppies will carry merle.

Cost Considerations

Merle testing typically costs between 40 and 80 pounds per dog, depending on the laboratory and whether it is ordered as a standalone test or part of a broader panel. Some breeders hesitate at this cost, particularly when testing multiple dogs.

I ask such breeders to consider the alternative costs:

• Veterinary care for a double merle puppy: hundreds to thousands of pounds
• Lifetime support needs for a blind or deaf dog
• Reputation damage when buyers learn their puppy has preventable disabilities
• Emotional toll on breeder, buyers, and the affected dog
• Potential legal liability if the breeding was demonstrably negligent

Testing is not an expense. It is insurance against a catastrophe that no responsible breeder should ever risk.

Building a Testing Protocol

For breeders working regularly with merle-affected breeds, I recommend establishing a systematic testing protocol:

1. Test all breeding stock - Not just obvious merles, but every dog you intend to breed
2. Test before purchase - Request merle status documentation from any dog you are considering adding to your programme
3. Maintain permanent records - Keep copies of all test results, including the laboratory report with fragment lengths
4. Share results openly - Provide test documentation to puppy buyers and fellow breeders
5. Retest if uncertain - If results seem inconsistent with phenotype, test again through a different laboratory

The resources available for canine genetics education are better than ever. Combined with reliable testing, there is simply no excuse for producing double merle puppies through ignorance. Every affected puppy born today represents a failure of the breeding community to use the tools at our disposal.

Learn how to implement these test results in a comprehensive breeding programme that preserves the beauty of the merle pattern while protecting every puppy's welfare.