The Merle Coat: Acceptable in the American Bully Breed?

The short answer is no due to the severe health problems it can cause

Confident, extroverted and gentle, the American Bully makes a wonderful, loyal pet.

Well known for their amazing patience with children, they are courageous and trustworthy as well, and would gladly give their life in defense of their owners (although said owner would need to be just as calm as well as firm in their commends and consistent with their training).

One unusual attribute that American Bullies, as well as several other dog breeds, can sometimes have is a unique coat pattern that is known in the dog-breeding world as a ‘merle’ coat.

A merle coat pattern, truth be told, can be rather attractive and, for that reason, American Bullies with a merle coat are coveted by some dog owners and breeders.

Unfortunately, a merle coat pattern is also associated with a number of serious health problems and, for that reason, is not accepted by the American Bully Kennel Club and several other associations.

This article will go into the details surrounding the merle coat pattern, where it comes from, what causes it and why it is shunned by most ethical breeders and Kennel Clubs.

We’ll take a closer look at the health problems the merle pattern is associated with as well, and the debate that is raging as we speak in the American Bully community. Enjoy.

What Causes an American Bully to Have a Merle Coat?

Although a merle coat is often referred to as a color, it is, in fact, a mutation of a specific gene that alters the pigment in an American Bully’s coat.

One of the reasons that the merle coat is coveted by some owners and breeders is because it is unique to every dog, and so no two American Bullies will have the same pattern if they have the mutated merle gene.

When an American Bully that has the mutated merle gene is bred with one that does not, the resulting pups can be both non-merle and merle. Breeding one merle with another merle will usually result in several of the pups being merles and some being so-called ‘double merles’.

Unfortunately, this is what some breeders are doing and why there is a raging debate in the American Bully community right now because of the health problems associated with the merle mutation. (More on this later.)

What Characteristics Identify An American Bully as Having a Merle Coat?

American Bullies with merle coats are easy to identify due to the patches of hair in their coat with a unique pattern of diluted colors (pigments).

While some might call American Bullies with the merle mutation by several different colors, there are basically three (as of this writing) that are most common. They include ‘blue’ merles, ‘red’ merles and ‘cryptic’ merles.

1.) Blue Merles

blue merle dog

Although they are called ‘Blue Merles’ the fact is that this color of American Bully is actually gray with patches of black. In some types of lighting, a blue merle’s coat can appear to be blue, which is the reason for the confusion.

Their coat is very similar to a tricolor American Bully because it will usually be a combination of tan, white and black, although the black will sometimes be quite faded and appear gray.  A ‘bi-blue’ is also a possibility, which is when a blue merle has no tan in their coat at all.

2.) Red Merles

red merle dog

With more of a mottled pattern then the blue merle pattern, Red Merles are more tan and black, and many times can have very dark patches of color (although they can sometimes be quite pale as well).

Red merles are a bit more rare than blue because of the fact that, while all breeds can produce blue merles, only a smaller population of certain breeds can produce red. Red merles can have tan markings in their coat or not and still be called red merles.

3.) Cryptic Merles

cryptic merle colored american bully dog

Very occasionally you will find an American Bully that appears to have a normal coat but is, in fact, a merle and will pass on the merle genes to its puppies if bred. The reason for this rare coat, at this time, is unknown. This type of merle American Bully is known as a cryptic merle.

This means that it is confusing, mysterious or hard to understand why they have the merle gene but don’t show it.

One thing that’s very interesting about the merle gene is that it is dominant and so an American Bully with the merle gene will always have inherited it from one of its parents and will almost always pass it down to at least some of its puppies.

What Eye Color do American Bullies with the Merle Gene Usually Have?

american bully with blue eyes

The majority of American Bullies with the merle mutation will have two blue eyes although, occasionally, they can have one blue and one brown eye. Also, it’s not impossible for an American bully with the merle mutation to have two brown eyes but that seems to be the rarest combination.

What is the Difference Between a Single Merle and a Double Merle?

single merle dog

Every dog with the merle mutation has the genotype Mm. This is because of something called the M allele (an allele is an alternate form or mutation of a normal gene) and the fact that a merle has only a single copy of the M allele.

This, specifically, is the cause of this unique color pattern. An American Bully that is not a merle would have the genotype mm, while one that has the single merle gene would be an Mm.

One of the biggest debates in the American Bully community right now is whether or not a merle and another merle should be bred, something that can, and does, lead to a double merle, or MM genotype.

If and when two dogs with the merle gene are bred, about 1/4 of them would have the genotype MM, which is, as we mentioned, referred to as a double-merle as well as a double-dapple.

Interestingly, double-merles do not look like merles at all but, instead, have coats that are mostly white with very small merle patches here and there.

double merle dog

The reason for this is quite interesting; when an American Bully inherits one merle gene (Mm) it causes the unique marbling/ lightening effect, with a number of light spots randomly spread out throughout its solid color coat.

But, when an American bully inherits two merle genes (MM), this unique effect is doubled, creating many more light spots that make the coat appear to be almost a solid white color rather than marbled. All of this is due to a lack of the normal pigmentation that the merle mutation causes.

Double Merles can be the product of breeding two blue merles together, two red merles together or a red and a blue merle together. The chance of a double merle being born is 25%, more or less.

The genotype configuration for the merle mutation goes as follows:

  •           Non-Merle / Normal genes = mm
  •           Single Merle gene / heterozygous /single allele = Mm
  •           Double Merle gene / homozygous / double allele = MM

The reason that breeding two merles together is a point of contention in the American Bully community is that, without the normal pigmentation that they should have, double merles are much more prone to serious health problems including blindness, deafness or both.

It doesn’t always happen but, as any American Bully lover would hopefully agree, any time that it does happen is too many times.

The Ugly Truth Behind What Happens to Many Double Merle American Bullies

Knowing that the chance of health problems in a double merle American Bully is very high, they are often killed as puppies when they are born because, frankly, breeders have a hard time selling them.

This is often done before a breeder even knows if the puppy has health problems or not, which I think we all can agree is quite horrible. This is known as “culling” and, unfortunately, it happens more often than you might think.

Even if a double merle makes it to a shelter they will oftentimes have to be euthanized because very few people want to adopt what they consider a “defective” animal.

Some unscrupulous breeders will actually sell a double merle as a “rare white”  or ‘albino” American Bully to customers who don’t know the difference. In the worst cases, double merles are used as “bait dogs” in dogfighting matches.

The reason that these horrible situations happen more often than not is that unscrupulous breeders, knowing that a double merle can negatively affect their reputation, get rid of them to keep their breeding program going strong and making profits.

Why Do Some Breeders Still Choose to Breed Double Merles?

white merle dog

The answer to this question is frustrating at best and, at worst, should make any person who loves dogs quite angry. The simple fact is that, occasionally, double merles are created when two merles are bred accidentally.

While we don’t consider ignorance an excuse, the information being passed to the public isn’t always complete, which can lead to this oftentimes sad situation.

More of a problem, however, is when breeders knowingly breed merles together in order to produce a few single merle puppies for the unique and coveted coat colorings they offer. The fact is, many people find the merle mutation coat to be quite attractive and, in many cases, it is.

That being said, knowing that a double merle has a very high chance of being born with severe health problems like blindness and deafness should be enough to stop any ethical breeder in their tracks.

Still, the practice persists and disabled American Bully puppies are born with the double merle mutation only to be culled, sold to customers ignorant of their genetic predisposition to health problems, end up in shelters and get euthanized or, worst of all, are forced into the dogfighting ring and die there horribly.

What are some of the Health Problems an American Bully with a Merle Coat can Have?

The main reason that the merle coat and mutation are not acceptable by ethical breeders and most canine associations and kennel clubs is that the mutation, and lack of pigment that it causes, can lead to a number of health problems for the American Bully breed.

When an American bully is born with the mutated merle gene, random sections of its coat are diluted in color due to the lack of pigment, which leaves only patches of the dog’s original color.

These patches can be located anywhere on the dog (as opposed to a piebald dog that has patches only on its head and body) and can be of any size.

There are two different kinds of pigment in a dog’s coat, eumelanin and phaeomelanin.

merle dog health issues

The eumelanin pigment affects the colors black, blue (isabella) and liver, which means that any part of the dog’s body with these colors including the coat, ears, nose and/or eyes will be affected and thus merled.

While most heterozygous American Bully merles (Mm) are born free of underlying health problems due to the merle gene, homozygous (MM) or double merles are very commonly affected by several. They include;

  •           Deafness
  •           Blindness
  •           Sun sensitivity
  •           An increased incidence of skin cancer
  •           Skeletal abnormalities
  •           Cardiac (heart) abnormalities
  •           Reproductive system abnormalities

The eumelanin pigment is the cause of this, or rather the lack of pigment, because it is important for the proper function of both the eyes and ears as well as the dog’s skin (which is why cancer is so prevalent among double merles).

Some double merle American Bullies have so little pigment that they appear to be white or albino, which is why unethical breeders can (and do) sometimes sell them as ‘special’ dogs to unknowing clients.

If you want more information about the merle coat mutation from a trusted source, use this link to go to Dr. Sheila Schmutz’s website and her report on The genetics of coat color and type in dogs.

What Can and Should Be Done to Stop American Bully Merles from Being Bred?

There are several ways that the breeding of American Bully merles and double merles can be slowed down and stopped. One of the easiest and most important is education.

An ethical breeder should educate anyone who buys an American Bully to the fact that there is a gene mutation in the breed that can cause this situation. 

This is especially true about double merle puppies since unethical breeders, as we’ve already mentioned, will often try to sell them as “albino” or “rare white” American Bully pups to unsuspecting clients.

Maybe more importantly, kennel clubs and official canine organizations should be discouraging the breeding of both American Bully merles and double merles. To the end, The American Bully Kennel Club (ABKC) does not accept the merle color in the American Bully breed.

merle american bully dog

As their literature states; “It is a disqualifying fault. Disqualifying fault; merle pattern/ blotched per competition.” The full ABKC standards list can be found here.

The American Dog Breeders Association (ADBA) stated years ago that “The registration of merle puppies in the litter from ADBA registered dogs with the breeding date after February 21, 2005, will no longer be accepted”. 

The ADBA also went on to state that “It is our recommendation that all merle pups born in a litter should be spayed or neutered and placed in pet homes only.

Full disclosure of the potential health problems that can result in these dogs should be made to their pet owners”. The full transcript can be found here.

The United Kennel Club (UKC) also disqualifies the merle mutation in the American Bully breed on several different fronts, including ‘color’.  From their website;  “Color- Any color, color pattern, or combination of colors is acceptable, except for merle. Disqualifications: Albinism. Merle.” 

They go on to say that a dog with a disqualification “must not be considered for placement in a conformation event, and must be reported to UKC.” The full UKC standards list can be found here.


dog with merle coat

While an American Bully with a merle coat can undoubtedly be attractive, the fact is that the merle pattern has no place in the breed and should be prevented and/or stopped.

We hope that our readers agree with this sentiment, especially keeping in mind the dire health problems that an American Bully born with a merle mutation can have, especially a double merle.

When you also consider the fact that many double merle puppies are culled at birth, and that adult double merles are often euthanized or die in dogfighting rings, the awful gravity of the situation is apparent.

The American Bully is a wonderful, loyal and kind dog no matter the color of its coat, but when that color is bred only to suit the fancy of a small group of people it becomes both immoral and unethical. This is a passing fad that, hopefully, will stop sometime very soon.

The fact is, a responsible breeder should refuse to breed American Bully merles and also refuse to stud their dogs to an American Bully with the merle mutation.

Thank you for reading. We hope you enjoyed this article and that it answered all of your pressing questions. If you have more, need advice or would like to leave a comment please do so in the space provided and best of luck with your American Bully!

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  1. How interesting that you mention a merle coat in an American bully. I want to get a dog this spring. I will find a great American bully puppy breeder nearby.

    1. Well Tiff, let me first start by stating that even Dave Wilson of the ABKC will admittedly tell you that the merle bully’s are in the original studbooks that started the breed. Next I will state, in my opinion, the mis-information your article presents about how breeding merles to a non-merle presents health problems. I have produced several litters, all embark DNA tested, that have not one genetic carrier. This article is severly misleading to the general public. Now, what i will agree with is the breeding of MM (double merles). I as well believe this should be outlawed. Period. This is the only point I can agree on. Some of the most correct structural Bully’s world-wide are merle or brindle. That isn’t public opinion, that’s traveling the globe for ABKC shows, IBRC shows, laying hands on the dogs, seeing their DNA tests myself personally. The history of the breed started with merles, the ABKC will not accept the coat pattern to be shown; however, they will register the merles as ” blotched”. Explain that. The ABKC will not recognize the merle because it does not have to. We are talking about a multi-million dollar a year registry that will register your merle, you just can’t show it. Hence why almost every other registry formed DOES allow merle to be shown. If pigmentation is your last leg to argue on, then blues should far outweigh the allergy problems some might consider when speaking about merles. I’ve had way more allergy issues with blues than I’ve had with any merle bully. There are literally wrote in addendums to contracts regarding blue bullys allergic skin and coat problems. In closing, proper information and education on the matter is seriously needed in the community as a whole. Thank you for your time.

  2. We have Casper in our home in the U.K. where they are not recognised as breed. He is 8 months old and 110 pounds. Really good natured with other dogs and people.

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