The Merle Bully: What You Need To Know | Unsuspecting Pet Owners

Unsuspecting pet owners are often beguiled by the opportunity to own a rare color dog. American Bullies come in several unusual colors, and one of them is merle. Merle involves both color and coat pattern differences making their appearance interesting and striking. But is it wise to get a Merle Bully? and what do you need to know before making the decision? 

Merle Bullies result from a genetic mutation that affects the pigment in their bodies. There are Blue Merles, Red Merles, and Cryptic Merles. Merle is a rare color in American Bullies but is becoming more common due to its popularity. Merle Bullies can have significant health problems.

As a veterinarian who loves American Bullies and owns a rescued Bully, I follow the developments in the breed closely. Rare and unusual color American Bullies should always be investigated carefully, as their health may be affected.

merle bulldog

What Causes An American Bully To Have A Merle Coat? 

American Bullies have merle coat colors when they have the merle gene. They are sometimes referred to as Merle Bullies.

Ever wondered what genetics make up an American Bully’s unique merle coat? To understand the answer, you need to know a bit about basic canine genetics – but don’t worry, I’ll keep it simple!

Each trait or characteristic is determined by two genes; one from each parent. Usually, at least one of these will be dominant and can visibly affect your pup with colors, patterns or traits being expressed in their fur.

A dominant gene always expresses itself, or in other words, affects the dog physically. You will see the color, pattern, or trait in the dog.

 If a recessive gene occurs with a dominant gene, the recessive gene will remain ‘hidden,’ but the dog will be a carrier for that characteristic.  

However, if both are recessive – then only those dogs carrying them on both sides can show this type of unusual blue-mottled hue that Merle American Bullies can have.

What Genetics Result In Merle Bullies?

Each gene pair is seen at a particular location on the DNA strand, referred to as the locus. Every dog has genes in the M locus, where the merle gene is located.

Merle is a dominant gene meaning and is written with a capital M. Non-merle is recessive and written with a lowercase m.

A Merle Bully can have the following genetic pairing at the M locus:

1.      Mm

2.      MM – these are Double Merles, and we will speak about them later in the article.

The merle coat will be seen whether there are two merle genes or only one because it is dominant.

Dogs without the merle color will always have an mm pair at the M locus. They do not carry the merle gene at all.

This is a very basic explanation of the complex genetics of Merle Bullies, but if you are interested and want to read further, you can click here.

What Does The Merle Gene Do In American Bullies?

The merle gene is a color and pattern gene. It lightens the base coat in random unique patches which have the appearance of torn or jagged edges. It creates a mottled coat on a solid or piebald based coat.

There are four classes of merle markings on Merle Bullies:

1.      A dog may have minimal darker colors, with the patches being quite small. The effect of the merle gene on the pigment is extensive, and most of the dog will be a lighter color.

2.      The standard or normal merle distribution has approximately 50% of the coat that is lighter, and the other half consists of unevenly sized dark patches. This is the preferred patterning for merle.

3.      A blanket merle is a dog with large dark patches or areas of the body.

4.      A minimal merle is a dog that is almost completely dark with a few small patches of merle coloring.

The distribution of the merle influence is unique to each dog, so no two Merle Bullies will ever have the same markings.

Merle Bullies are truly one-of-a-kind! Not only will they have unique coat colors due to the merle gene, but their noses and eyes may also show signs of altered pigmentation. For example, you might find a black or red nose with a pink patch – otherwise known as butterfly noses. Or even half one color on the top and bottom halves being different shades blended together.

You can thank eumelanin for this variety. It’s responsible for producing not just traditional coloring such as black and brown and is also responsible for liver, tans, and blues.

While there isn’t much effect phaeomelanin has in terms of pigment alteration affecting these pups’ base coats (unless exceptions occur), owners should still expect an inviting array of expressive features that make every Merle Bully special.

Why Do People Breed American Bully Merles?

Merle coats are beautiful and unique, with each dog having a different pattern. People generally shop with their eyes and seldom do research when considering purchasing a dog. This is true for Merle Bullies as well.

Breeders take advantage of the general public’s ignorance and cater to their demands by breeding Merle Bullies. Breeders charge a higher price for Merle Bullies than standard-colored American Bullies.

Breeding Merle Bullies requires the breeder to educate themselves regarding genetics and inheritance, but few do. With the chance to charge $ 20,000 USD or more for a Merle Bully puppy, many breeders forget their ethics.

Are Merle Bullies Rare?

Merle Bullies are a rare sight in the American Bully world because they carry an unusual M gene. While merle Bullies may seem rare, their numbers are steadily growing as some unscrupulous breeders attempt to capitalize on the color.

Sadly, this increases the risk of negative impacts from a genetic perspective for potential pups. Uneducated people will begin breeding Merle Bullies without knowing the impact of the genes. This will contribute to an increasing Merle Bully population and an increase in associated health problems (see below).

American Bully Merle Coat Colors

American Bullies come in various coat colors. They may be tan, fawn, grey, brown, black, red, blue, or pied. Merle will affect all these colors but red. Red is rarely affected.

Blue Merles

Blue Merles are American Bullies that have a black base coat. The merle gene dilutes the black pigment unevenly across the dog’s body, giving the dog a greyish-blue color with darker or black patches.

Blue Merles are similar to tricolor American Bullies as their darker patches may include tan and black or grey with white chests.

A Bi-Blue Merle is a dog with no tan markings. These dogs are easy to distinguish from tricolor Merles.

Red Merles (Orange Merles)

Red Merles do not have red-based coats. They have a brown-base coat which is modified by the merle gene. This produces a red or orange tone to the dog’s coat and is why they are called Red Merles.

The merle may make parts of the coat look cream or whitish, and the darker spots may be reddish brown, copper, or liver. Red Merle Bullies are not as common as Blue Merles and tend to be more mottled than the Blues.  

Cryptic Merles

Cryptic Merles are sometimes called Hidden Merles. The merle portion of the fur is tiny and may be disguised by white patches that normally occur on American Bullies, such as on the chest.

One clue is that the Cryptic Merle dog may have blue eyes. This dog should be genetically tested to ascertain if it is a Cryptic Merle, as blue eyes can result from other genetic anomalies.

Although a merle gene is dominant, the reason why these dogs do not show the gene clearly in their coat is a complex genetic issue. They can pass the merle gene on to their offspring. It is probably how the first merle American Bulldogs were accidentally bred.

Merle American Bully Eye Color

Merle genes in American Bullies affect all eumelanin in the body, including the eyes. The eyes of Merle Bullies are blue or heterochromatic (have one blue eye and one brown eye).

Merle Bullies can have two brown eyes, but this is rare. In some dogs, heterochromia may be expressed in one eye so that half the eye is blue and half the eye is brown.

In rare instances, the eyes may be green or a mixture of green and blue or brown. An entirely blue or green eye is sometimes called a glass eye. Brown eyes with some slight merling are referred to as standard eyes.

How Do You Breed Merle Dogs?

Merle dogs are bred by having one parent dog that is merle. The accepted breeding practice is to mate the merle parent with a non-merle dog. The result is that 50% of the offspring are merle dogs, and 50% are non-merle.

It does not necessarily mean that 50% will be merle, as the genetic lottery is a quirky master, producing surprising results at times. Each puppy has a 50% chance of being merle.

There are three ways that breeders produce Merle Bullies:

1.      The Designer Merle Bully is produced by breeding two American Bulldogs together, one of which is merle.

2.      The Standard Merle Bully is bred by breeding an American Bulldog to an American Pit Bull Terrier.

3.      The Hybrid Merle Bully is the result of breeding an American Pitbull Terrier with a hybrid dog. This is the least common way to breed Merle Bullies.  

Purist breeders usually choose to breed two American Bullies together as they wish to alter only the coloring and not the characteristics and conformation of the dog.

What Is The Difference Between Merle And Double Merle? 

 Merle dogs have only one parent that is a merle dog. Their genotype is Mm, or in other words, they only carry one merle gene. They are heterozygous for the merle gene.

Double Merle dogs carry two copies of the merle gene, so their genotype is MM. Another way of saying this is that the dog is homozygous for the merle gene.

Double merle genes affect both the eumelanin and phaeomelanin pigments. These Merle bullies are mostly white and may have a few small merle spots on the top of the head, the back, or the base of the tail.

Many Double Merles are completely white with no colored markings at all. Their noses are usually pink, and their eyes are almost always blue, but occasionally wall eyes or heterochromia is seen.

What Is A Tri Merle Bulldog?

A Tri Merle Bully has a base color plus tan and white. The base color may be any American bully coat color, such as black, liver, blue, or lilac.

A Tri Merle also has the merle gene, which affects the three colors.

Why Do Breeders Breed Double Merle American Bullies?  

Unfortunately, breeders often breed Double Merle Bullies out of ignorance. People believe that finding two Bullies you like and letting them mate is an acceptable way to approach breeding. 

The general public is unaware that responsible breeding requires scientific knowledge and careful planning. They do not understand the health implications of breeding two Merle Bullies.

The other reason people breed Double Merle Bullies is more sinister. Some breeders do not care about producing unhealthy dogs and are only interested in the money they can get by selling the puppies.

While there is public demand for Merle Bullies, unscrupulous breeders will continue producing them any way they can.

Pressure from the public demanding ethical breeding is the best way to stamp out breeding Double Merle Bullies. Educating the public is critical to this process. 

What Happens To Double Merle American Bullies?

The horrifying reality of what happens to unhealthy Merle Bully puppies will shock most people.

Very often breeders will euthanize or cull unhealthy Merle Bully puppies. They may do this by humane euthanasia performed by a veterinarian, or they may do it at home themselves. When done at home, the methods are painful and unkind, and the puppy suffers as it dies.

Some breeders dump their unhealthy Merle Bully puppies at animal shelters, taking no responsibility for the dog. In most cases, they do not even donate to the shelter.   

Sometimes breeders sell unhealthy dogs to uninformed people, who are left grappling with many health issues. Their new pet may have reduced life expectancy and poor quality of life. 

Do Merle Bullies Have Health Problems?

Most people think of melanin as only a pigment that has no other function. Eumelanin is important in the functioning of both the eyes and the cochlea of the ear.

Merle Bullies are susceptible to some eye and ear defects, but Double Merle Bullies are affected to a much greater degree. The Merle Bully usually still has enough pigment for their eyes and inner ear, so they have a lower percentage of defects. Double Merles have greatly reduced pigment and so are more likely to have health problems.

These are the eye and ear defects seen in The Merle Bully:

1.      Deafness in one or both ears. Heterozygous Merle Bullies have 2.7% in one ear and 0.9% in both ears. Double Merle Bullies have 10% deafness in one ear and 15% deafness in both ears. Other studies show up to 60% deafness in Double Merles.

2.      Micro-ophthalmia (small eyes) and lack of eyes can occur in Double Merles.

3.      Blindness in Double Merles can be up to 60%  

Other defects seen in Merle Bullies include:

1.      Heart defects

2.      Autoimmune diseases

3.      Allergies

4.      Skeletal and joint problems

5.      Hydrocephalus (too much cerebral-spinal fluid on the brain)

6.      Spina Bifida

7.      Cleft Palate

8.      Increased rates of skin cancer 

Should You Adopt A Merle American Bulldog?

Merle Bullies sometimes end up in shelters and deserve a home just as much as any other dog. If you want to adopt a merle bully, ask the shelter what the health challenges are of the individual dog.  

Ensure you can cope with any health conditions before adopting. Some people are wonderful homes for blind or deaf Merle Bullies. Other people are not equipped and bring the dog back to the shelter as they cannot manage.

Some Merle Bullies in shelters have no medical issues and were surrendered or confiscated for other reasons. They are just as affectionate and friendly as other American Bullies. You should adopt these Merle Bullies if you can and want to. 

Frequently Asked Questions

How Much Is A Merle Bully?

Merle Bullies vary in price. They usually start at $8,000 but can go as high as $ 35,000 USD.

Can you register a Merle Bully?

You cannot register a Merle bully with the American Kennel Club (AKC) or The International Breed Certificate (IBC). The American Bully Kennel Club (ABKC) and the American Dog Breeders Association (ADBA) also do not accept Merle Bullies.   

Can you breed two Merle Bullies?

Two Merle Bullies should never be bred. It causes severe health problems.

Are Merle Bullies Healthy?

Merle Bullies are prone to more health problems than other American Bullies. Double Merle Bullies have severe health problems.

Emily Andrews