We hope that you will appreciate us sharing our knowledge with you. We also hope that you will share with us, as we are always learning, and improving on our understanding. We want to thank the few, very kind breeders who have actually called and said THANK YOU to us for creating this section. We realize that there are many breeders who use our site, that we never hear from...so Thank you for expressing your appreciation, it means a lot to us!

If you have questions or suggestions to do with Color, PLEASE visit the Q and A Links section.

Please do not call for Color/DNA Questions. We appreciate your understanding that our phone lines are for our Clients & Customer Support.

Geneticists and Breeders have long been aware of several locations of chromosomes (loci), which are responsible for the color patterns we see in dogs. Each locus has 2 sides. Every puppy inherits one copy of each locus from Mom and one of each from Dad. This is true of ALL genetic traits. Each of these loci is responsible for one or more traits, either independently, or in conjunction with another locus. The simple rendition below can be applied to any single loci, such as the B loci.

LETS GET STARTED. LESSON 1A

LESSON 1B

LESSON 1C

LESSON 1D

COLOR GENETICS BASICS Lesson 2

The simple rendition below is applied to 2 single loci, D & B. You can see how complicated these scenarios can be. Imagine you are dealing with 3, 4, or more!

LESSON 2...showing only 2 of the 81 combination possibilities.

LESSON 2A

LESSON 2B

LESSON 2C

COLOR DNA TESTING

TESTING CENTERS & INFORMATION

Introduction

There are thirteen + different locations or loci on the chromosomes that have a combined effect to determine the color of a particular dog. At each locus, there can be found many variations or alleles that can be dominant or recessive in nature. Chromosomes come in pairs, so each dog has two different alleles at each locus on the chromosome pairs, and depending on the dominance of the alleles contained at the locus determines the color of the individual dog. The genetic material of the dog is inherited one half from the mother and one half from the father. The final characteristics of the offspring is determined by the new combination that results and the dominance, recessive nature, & hierarchy of the alleles that they inherit.

We have used UC Davis for many years and recommend them above all other labs for color testing. The Results in the Charts below uses UC Davis' letter system. Other labs have different lettering systems, which is very important to differentiate. CREDITS: The reading and results in the chart, are predominantly excerpts from the UCDavis Website.

DNA Q & A

Please do not call for DNA/Color Questions. We appreciate your understanding that our phone lines are for our Clients & Customer Support.

Use these links to get answers that you do not find here on our site.

Face Book EMBARK:

https://www.facebook.com/groups/1049060571845745/

Face Book COAT COLOR AND GENETICS:

https://www.facebook.com/groups/295684027143185/

DOG GENETICS: http://www.doggenetics.co.uk/

TESTING CENTERS

HEALTH DNA

HEALTH DNA INFO AND TESTING

OUR CONTRIBUTION

Rare Bulldogs has started its Health Testing in early 2017. This is an ongoing process that will take several years to complete. As per our Geneticists recommendations, we will not take our affected bulldogs out of our breeding programs as this would be very detrimental to the breed as a whole....our breed is already in trouble as you will see in the article referenced below, PLEASE read it!

Therefore, we will start with our keep back babies for our program, striving to keep breeders that are clear or at the very least, only carriers of the 3 disease genes mentioned here. If we ALL do this, we will bring back our breed. Our Breed is in so much trouble, that scientists are calling the English Bulldog Breed a DEAD END!

Rare Bulldogs considers it our duty to protect the Bulldog aka English Bulldog, our very special breed. Most consider the Bulldog an unhealthy breed. We do not. When ethical, knowledgeable breeders use healthy dogs in their programs, the outcome is healthier puppies overall. Our breed Standard reflects necessary qualities needed to produce healthier puppies in our breed.

As many may know, there has been a recent Study in the genetic diversity done on the Bulldog Breed that is rather alarming. We, as CBCA Rare Color Breeders are honored to say that we have made large strides in hopefully improving on this study. In the last 10 years, because of the diversity in adding the Rare Colors to our breeding programs, most Rare Color Breeders have seen a significant difference in the overall health of puppies produced, some in less than 3 years.

HEALTH IN GENETIC TESTING

Like all breeds there may be some health issues related to the Bulldog breed. Because they are a brachycephalic breed, bulldogs will often have breathing problems which are related to their elongated soft-palate blocking their airways. If this were to become a chronic problem, surgery may be an option. Other health issues reported in bulldogs are cherry eye & skin infections which can be easily treated by cleaning the skin-folds regularly. Some Bulldogs will be faced with health issues in their lives as are all dogs, but the majority of well-bred Bulldogs are healthy dogs. Work with a responsible breeder, gain the education you need about specific health concerns within the breed.

Read the study:

https://cgejournal.biomedcentral.com/articles/10.1186/s40575-016-0036-y

What Science Alert had to say about the study. Personally, I bet if the study was done on our Rare Colors, the findings would be vastly different.

https://www.sciencealert.com/english-bulldogs-are-at-a-genetic-tipping-point-study-finds

Read in depth information on Bulldog Health and DNA Testing HERE.

DM...ENGLISH & FRENCH BULLDOGS

Degenerative myelopathy (DM) is a progressive disease of the spinal cord in older dogs, onset typically between 8 and 14 years of age.

It begins with a loss of coordination (ataxia) in the hind limbs. The affected dog will wobble when walking, knuckle over or drag the feet. As the disease progresses, the dog's hind legs will weaken and eventually the dog will be unable to walk at all, and can experience loss of urinary and fecal continence with eventual weakness in the front limbs. Fortunately, there is no direct pain associated with Degenerative Myelopathy.

A small percentage of dogs that have inherited two copies of the mutation will not experience symptoms at all. Thus, this disease is not completely penetrant, meaning the disease does not affect every dog that has the genotype.

Ethical breeding practices with this disorder:

No restrictions on unaffected dogs.
No restrictions with an unaffected to a carrier. If your breeding dog is a carrier, it is a must to test the intended mate to be unaffected.
Restriction on breeding two carriers.
Restriction on breeding fully affected to a carrier. Intended mates to fully affected should be clear.

HUU...ENGLISH & FRENCH BULLDOGS

The Hyperuricosuria mutation is autosomal recessive. Both parents will need to be carriers of the mutation to pass it onto their offspring. Only individuals that have two copies of the mutation, have a higher risk of developing clinical signs of the disease. Carriers of only one copy of the mutation will not develop the disease.

Dogs with this genetic mutation metabolize waste products as uric acid in their urine, this condition that predisposes dogs to bladder stones that can result in urinary obstruction. The uric acid forms into hard stones in the bladder, causing pain and inflammation as the stone moves through the urinary tract.

A dog that has difficulty urinating or appears to have an inflamed bladder may have HUU. Other signs can include blood in the urine and frequent urination. If the dog is unable to pass the urate stones without medical intervention, surgery is required to remove them. If the urinary tract is blocked, the condition can be life threatening. HUU is uncomfortable and painful for the dog.

Carriers will not show any symptoms of HUU. Affected dogs may not show any signs, so it is important to test dogs for HUU prior to breeding.

Ethical breeding practices with this disorder:

CMR1...ENGLISH & FRENCH BULLDOGS

Canine Multifocal Retinopathy (CMR), a recessive eye disorder, is known to affect several breeds including the English Bulldog. This causes raised lesions that form on the retina and alters the appearance of the eye but usually does not affect sight. These lesions, looking somewhat like blisters, vary in location and size. Typically they are present in both eyes of the affected dog. Lesions may disappear, or may result in minor retinal folding. Symptoms usually appear when a puppy is only a few months old, and generally do not worsen over time.

Since CMR1 is recessive, both parents would need to be carriers of the mutation to produce an affected puppy. Breeding two unaffected or one unaffected and one carrier will not produce affected offspring. However if one parent is a carrier, a percentage of the offspring will be carriers. It is necessary to test for the presence of the CMR mutation before breeding, so as not to breed two carriers together, and unwittingly produce a fully affected puppy. Dogs have two copies of the mutation are susceptible to develop retinal deformation, although fully affected dogs do not always develop into disease.

In most cases, treatment is not required.

Ethical breeding practices with this disorder:

HC...FRENCH BULLDOGS

Cataracts are a clouding of lens of the eye caused by a breakdown of tissue in the eye. This generally results in an inability to see clearly, and can cause total blindness.

In canines, mutations that result in cataracts can be passed to offspring and is known as Hereditary Cataracts. A mutation in the HSF4 gene causes this type of cataracts in several breeds of dogs. In this case, the dog is typically affected bilaterally with both eyes affected by the disease.

They usually begin small and grow progressively, though the speed of growth is highly variable. Some cataracts will grow so slowly that the dog’s vision remains relatively clear, while others will grow such that the dog will quickly go blind. Corrective surgery is possible, though it is costly and is not always effective. One HSF4 mutation causes the recessive form of HC in Boston Terriers, Staffordshire Bull Terriers, and French Bulldogs.

Because it is recessive, a dog must have two copies of this mutation to experience this form of cataracts. Incomplete penetrance means that a dog that has this mutation will not always develop HC. It is likely that a secondary gene interaction occurs in the small percentage of dogs possessing the HC mutation but do not develop cataracts, however, this interaction is not yet known.

It is important to note that not all cataracts are hereditary. Cataracts can also be caused by old age or injury. Also, cataracts that occur in different regions of the lens can also be familial, but not necessarily attributed to this gene mutation.

Ethical breeding practices with this disorder:

INBREEDING COEFFICIENT

Does it matter? Absolutely.

Close inbreeding has been linked to decreased longevity in canines. One study showed up to 4 years lost off the average age of certain breeds.

Rare Bulldogs takes great care to try & produce the healthiest puppies we can. One of the factors we use is to calculate our INBREEDING COEFFICIENT for each litter. Up to 10% is widely accepted, and most of the time we stay at 10% or below. Studies show that staying below this percentage greatly increases longevity in puppies produced.

Rare Bulldogs INBREEDING COEFFICIENT is stated on every Pedigree

FRENCH BULLDOG CHOCOLATE

There is a lot of controversy over the Chocolate Colored French Bulldog (FB). This article will most probably upset many FB breeders, BUT, science is science and cannot be denied. This information will include experienced opinions from breeders and scientific fact from Genetic tests and input from Geneticists and Doctors of Veterinary Medicine, professionals in the field.

THE FRENCH BULLDOG AND CHOCOLATE COLOR

Our main topic here is testable and non-testable chocolate color in French Bulldogs. This has now been found and is called the Cocoa Variant. The Normal Chocolate is the same test that has always been around for chocolate (brown) for years and is used in many breeds.

For many years there have been visually chocolate FB’s that have tested BB…non chocolate, so there ARE chocolate FB’s that definitely have chocolate hair and a chocolate nose that test BB. We now know these dogs are full Cocoa aka coco. Recently, we have quite a few FB lines that do test Bb or bb, and the dogs in those lines that test bb actually look Chocolate as you can see in the photos included herein.

A lot of people/breeders claim that these lines are mixed with other breeds to have brought the testable b in, even though these dogs are visibly chocolate, which is ironic since these same ones claim they have chocolate FB’s that test BB and also do not look chocolate but rather, black, faded black, or seal with a bronze or other color undertone. Not one of these ones can produce any proof that the testable lines are mixed, while at the same time, many of these Bb or bb dogs have been parentage DNA tested and have been found to be 100% FB. Therefore this claim of mix breeding is 100% unsubstantiated.

From the Geneticist: "The French Bulldog has two ways to be chocolate. One we can test for, but has been historically rare in the FB, and one that has just been discovered, and seems to be the most common way the FB are chocolate. Recently, we are seeing more FB show up with the testable chocolate."

TESTABLE VS NON TESTABLE CHOCOLATE

UPDATE! 2020 There has been a new Brown Variant discovered that can be tested for, which explains the many Chocolate French Bulldogs that have tested BB in the past. It is called the Cocoa Gene.

Testable: bb

Non-Testable (now testable): coco

Pre 2020: The French Bulldog and Chocolate Color

Our main topic here is testable and non-testable chocolate color in French Bulldogs. For the purposes of this article, we will use the term “Normal Chocolate” for the testable, and “Mutated Chocolate” for the non-testable. The Normal Chocolate is the same test that has always been around for chocolate (brown) for years and is used in many breeds. The Mutated chocolate is actually more common in FB, but the gene/mutation/modifier has yet to be found.

For many years there have been visually chocolate FB’s that have tested BB…non chocolate, so there ARE chocolate FB’s that definitely have chocolate hair and a chocolate nose that test BB. This Mutated Chocolate Gene or Modifier for this type chocolate has yet to be discovered and therefore no test is available at this time for those dogs. Recently, we have quite a few FB lines that do test Bb or bb, and the dogs in those lines that test bb actually look Chocolate.

Not one of these ones can produce any proof that the testable lines are mixed, while at the same time, many of these Bb or bb dogs have been parentage DNA tested and have been found to be 100% FB. Therefore this claim of mix breeding is 100% unsubstantiated.

From the Geneticist: "The French Bulldog has two ways to be chocolate. One we can test for, but has been historically rare in the FB, and one that is still unknown, and seems to be the most common way the FB are chocolate. Recently, we are seeing more FB show up with the testable chocolate."

Not unknown any longer! Read on.

Cocoa: A brown coat color resulting in a slightly darker coat than the brown color caused by other variants. This color is seen in French Bulldogs and was previously referred to as non-testable chocolate.

Alleles:

N: Non-cocoa

co: Cocoa

Results:

NN: does not have the cocoa variant.

N/co: carries one copy of the Cocoa Variant

co/co: carries 2 copies of Cocoa

PARTIAL EXCERPTS FROM UCDAVIS

There are several known variants that result in the chocolate color in dogs. These known variants do not account for all chocolate in dogs.

The cocoa variant is a different gene and is therefore not TYRP1.

In French Bulldogs, a variant associated with a visually distinct chocolate phenotype was identified in the Hermansky-Pudlak syndrome 3 (HPS3) gene. Dogs with the HPS3 gene variant are visibly darker brown than the phenotypes associated with the previously described TYRP1 brown allele (b).

The canine cocoa variant is a single base change in the HPS3 gene.

The variant associated with the cocoa phenotype is recessive. Thus, two copies must be present for the dog to appear chocolate.

Data suggest one copy of cocoa (carrier) and one copy of any of the previously described gene variant (carrier) for brown will not result in a brown phenotype. Dogs with two copies of the cocoa variant may be cocoa, however the final phenotype of the dog is dependent on the alleles at other coat color loci.

At this time the interaction of cocoa and the other brown allele is not understood. Therefore, it is not yet possible to predict the phenotype of a dog with two copies of cocoa (co) and two copies of the TYRP1 brown (b).

At this time, it is also unknown if the cocoa variant is found in other dog breeds. just been discovered, and seems to be the most common way the FB are chocolate. Recently, we are seeing more FB show up with the testable chocolate."

Contributions from experienced Breeders

CREDITS: Huge thanks to Rick Pez of French Bulldog Breeders and Joyce Wild of J. Wild French Bulldogs for their contribution of knowledge, photos, and dna.

RICK PEZ

I have personally found about 23 other breeders with unrelated lines that have Normal Chocolate. Duglas Andy Pankratz had his first Normal Chocolate in 2007 and his first Lilac (also called Isabella) in 2009. Everyone has a theory on how the gene came to be or why it hasn't really been highlighted until recently. My simplest explanation is its a recessive gene that doesn't work with the more common mutated gene so if someone is producing the opposite colors and sells chocolate carriers to each other and all you get are black dogs, well, the breeder thinks they got ripped off, but in actuality they might have created dual chocolate carriers.

Hershey and his sister, pictured here, are DNA testable Lilac French Bulldogs, leaving no question as to whether they are TRUE LILAC.

JOYCE WILD

When you have a visually brown/chocolate dog the color can come from 2 different genes. The most common right now is the Mutated chocolate which just means the gene that causes the color change is not the traditional chocolate and has risen from a DNA mutation. The location for this type has not been found and currently cannot be tested for. The other less common in the FB (but found in most other dog breeds) is the Normal Chocolate. It is called Normal chocolate because it is what you normally see in most dog breeds and you can actually DNA test (bb) to verify if the dog has that DNA.

Even a carrier of that type of chocolate will show up as Bb. The Normal Chocolate also has a consistent true chocolate color. They do not get dark almost black fur or noses that are almost black. You can visually tell they are chocolate. Some Mutated Chocolate dogs will be hard to distinguish from a black dog.

Normal Chocolate: a dog that exhibits the colors of brown skin pigment (such as the nose) and eumelanin fur. All black pigmented fur will show as brown/chocolate color. This type of chocolate will always test as bb on the chocolate DNA panel.

Mutated Chocolate: a dog that may exhibit a brown tone to fur or pigment. This type of chocolate will not show up on a DNA test so the results will show BB.s.

I have a problem when people state a hypothesis as a fact. There are no facts to support anyone saying that Normal Chocolate never existed in FB’s and that the bb dogs are mixed. Before the explosion of the internet there were so many things that were never publicly known about a lot of lines, breeds, breeders, etc. The mutated chocolate that cannot be tested for has not been documented as far back as the Normal Chocolate. I have both types of chocolate and have puppies that actually carry both types. I would really like to produce a puppy that is homozygous for both types of chocolate. Once the location of the allele is found for the Mutated Chocolate, then it can be correctly labeled. Not all lines are DNA tested so it is impossible to prove any of the hypothesis that people have stated. Keeping that in mind I do believe that some breeders may have infused the color unethically, but there are many ethical breeders who have not. I feel there are a lot of purebred dogs that have and still show up with DNA that we may not have expected. Hershey, pictured above and his sister, pictured to the right, are DNA testable Lilac French Bulldogs, leaving no question as to whether they are TRUE LILAC.

JOYCE WILD

This photo is the original chocolate FB that anti-color breeders of FB’s have been posting, it is the kind of chocolate you can tell by visual verification. Breeders started noticing the blue in FB’s were selling for so much money, so they started to selectively breed for chocolate, the Mutated Chocolate. So the FB’s that carried Normal Chocolate were not used as purposeful, and it became less and less common. Therefore people in the FB community got educated on the Mutated Chocolate and the Normal Chocolate gene got forgotten. Most of those that did test for b were hushed by others thinking that they weren't true. People started incorrectly believing that being a FB could not be DNA tested for chocolate. The truth is that the mutated type of chocolate is what cannot be tested rather than the breed.

FB’s are found to have a few genes not common in other breeds. Now some of the Normal Chocolates have come into the public eye rather than being hidden. The Bondar/Duglas line has become very populous and people are starting to find out about them again. Just because it is a different chocolate than some have been breeding for, does not mean they are any less a FB than any other FB out there. There are recessive traits that can hide behind certain lines for years before they are known. They can be there for 1 generation or 20 generations. I have a separate line that carries the same type of chocolate. Because mine were only carriers, the DNA has been running behind the generations unknown. I was unaware until one of my dogs had a full panel DNA test and surprised it was there. There are multiple dogs around that do test positive for the chocolate gene but are carriers so unless the ones that have these dogs tell people, no one would know.

That being said, it is a pet peeve of mine when people say they are mixed or say they are not true chocolate FB’s. This type of chocolate has been documented long before the Mutated Chocolate ever was. Eventually scientists may find the gene responsible for the Mutated Chocolate gene (which is also documented in some lines of beagles). But until then we won't be able to test for it.

HERIN CHIN

I love this photo explanation. Thank you Herine for allowing us to use this here!

Visit her instagram page here: https://www.instagram.com/hella.isabella.frenchie/

SCIENCE DON'T LIE! HERSHEY'S DNA FOR COLOR AND PARENTAGE

NORMAL CHOCOLATE LITTER BY JOYCE WILD + DNA

THE FRENCH BULLDOG AND RED EYE GLOW

The red eye glow has a simple Scientific explanation. Many FB breeders will not agree with these findings, because they show that red eye glow does not prove the dog is truly a Lilac, since Chocolate and Blue dogs, can and do, have the red eye glow. Red eye Glow simply put is, a lack of pigment (color) in the back of the dogs eye.

All the information below is excerpts from scientists and doctors. This is not my opinion, but scientific fact.

Science don't lie!

Red Eye Glow Explained There’s a simple scientific explanation for why flash photography often results in eye glow, it’s all about the construction of your dog’s eye.

In dogs and many other animals, the retina has a reflective layer behind it called the tapetum lucidum, which acts like a mirror, reflecting light at the back of the eyes. The reflective layer is what helps dogs see better at night. Light is reflected outward, giving the dog's retina a second chance to absorb the rays. Light that is not absorbed exits the eye, appearing as the eye glow.

This is what takes place when you snap a flash picture of your pet. Individual dogs have different colored tapetum, which is why some dogs’ eyes take on a green glow, others a yellow glow, and others red and so on.

Eye Glow occurs in a wide variety of colors including white, blue, green, yellow, pink, andred. Some dogs lack pigment in their tapetum lucidum. In these individuals their eye glow is red, as it is in humans. These dogs could be any color, although it is seen more in the dilute colors.

The color of this tapetal layer varies to some extent with an animal's coat color. A black Labrador retriever, for example, will usually have a green tapetal reflection. A buff Cocker spaniel will generally show a yellow tapetal reflection. Most young puppies and kittens have a blue tapetal reflection until the structures in the back of the eye fully mature at six to eight months of age.

Color dilute dogs such as chocolate, blue, and lilac, may have no tapetal pigment, and may therefore exhibit a red reflex just like human beings. Note that this includes all dilute colors in dogs, not just lilac. If your dog consistently has red-eye in photos, he might not have pigment in the tapetum. This means the red is coming from blood vessels at the back of the eyeball.

Credits:

https://www.canidae.com/blog/2013/03/why-do-my-dogs-eyes-glow-in-dark/

https://www.scientificamerican.com/article/why-do-dogs-get-blue-not/

https://healthypets.mercola.com/sites/healthypets/archive/2015/01/09/dog-eyes.aspx

Dr. Becker

https://www.petplace.com/article/dogs/pet-behavior-training/why-do-dogs-eyes-shine-in-photographs/

https://en.wikipedia.org/wiki/Tapetum_lucidum

4

THE MERLE CONTROVERSY AND AKC BULLDOGS (ENGLISH BULLDOGS)

We use UC Davis for our MERLE Testing

https://www.vgl.ucdavis.edu/services/dog/Merle.php

This page is not just my opinion. Every word on this page has been taken from articles of Scientists, Geneticists, Doctors, etc. all of which can be found by the links at the bottom of this page. It took me 5 months to read and go through all the websites and articles and excerpt the pertinent info that applies here.

So many people want to swear that English Bulldog breeders are mix breeding and hanging papers to get Merle Bulldogs. Most believe whatever they are told, or what they read without any backing to prove the belief, yet they still believe it and will actually accuse others of wrongdoing without any facts to back up the accusation.

That is pretty sad since there are many VERY reputable breeders that have a conscience and ethics....so I have compiled some info here, that can be backed up with science, and by Professionals with the education to state what is correct.

We are not so misinformed, though that we do not realize that there are breeders who HAVE cheated, mixed, and hung AKC papers taking shortcuts to get the Merle in their program. This makes it even harder for the ethical breeder of Purebred AKC Merle English Bulldogs.

As for our breeding program, we have parentage DNA with AKC on all our dogs associated with our Merle Program. Our Merles are PUREBRED AKC Bulldogs (English Bulldogs). AKC themselves list ALL Breeds in connection with the Merle pattern as do others as you will see below.

Hidden Merle Facts

Merle can be hidden by other genes, and patterns, sometimes for long periods of time. This is why the merle gene can and has ALWAYS been in EVERY breed and is backed up by scientific fact.

Hidden merles are merle dogs who do not exhibit the merle pattern because their coat color does not show the pattern. Merling is not normally shown in red, gold, fawn and cream coat colors. The hidden merle can be distinguished only by a genetic test.

1. Recessive Red: Merle can be completely hidden by recessive red, as recessive red dogs can't make eumelanin pigment and merle only affects eumelanin. A recessive red merle is known as a phantom, ghost, or cryptic merle.

2. Sable: A clear sable (dog with a red coat, but no visible black sabling) will also not show any merling because there is no eumelanin to be merled, unless it also has a mask (which does show merling).

Shaded sables will often show merle at birth, but it tends to fade as the dog grows up, so all that remains on an adult is usually a few darker brownish patches on the coat (which can be hidden very easily by thick or long fur).

3. The greying gene can also make it very difficult to see merle markings.

4. The dilution gene (dd), can also hide the merle because it dilutes the patches to roughly the same color as the base.

5. Brindle: Merle can be very difficult to see on a brindle too, due to the stripes. Brindle can hide merle, merle can hide brindle, or they can mix.

6. Heavy Markings: Merle can be hidden if the dog has very heavy markings, so a black merle could appear completely black if the patches are large enough (a cryptic merle).

Partial Excerpt from the UCDavis Website

https://www.vgl.ucdavis.edu/services/dog/Merle.php

Merle is an incompletely dominant coat color pattern characterized by irregularly shaped patches of diluted pigment and solid color.

Merle only dilutes eumelanin (black) pigment; dogs with an MC1R ee genotype (recessive red) have no black pigment, thus do not express merle but can produce merle offspring. There are 3 alleles (variants) for merle: merle (M allele, SINE with longer poly-A tail), cryptic merle (Mc allele, SINE with shorter poly-A tail) and non-merle (N allele, no SINE insertion).

Dogs with cryptic merle (also called phantom or ghost merle), typically display little to no merling and some may be misclassified as non-merles.

Inheritance of merle is genetically unstable for both M and Mc alleles. During DNA replication and cell division, M may occasionally undergo poly-A tail reduction to produce Mc (germline rate of 3-4%) while Mc may undergo expansion and revert to M. Because of the complexities of merle inheritance, and potential health concerns, DNA testing is recommended to establish the genetic make-up of dogs for the merle gene for those breeds where this color dilution pattern is present.

The Veterinary Genetics Laboratory is licensed to offer the merle test.

Results are reported as:

M/M 2 copies of merle are present (double merle)

M/Mc 1 copy of merle and 1 copy of cryptic merle are present

M/N 1 copy of merle is present

Mc/Mc 2 copies of cryptic merle are present

Mc/N 1 copy of cryptic merle is present

N/N No copies of merle or cryptic merle are present

References: Clark LA, Wahl JM, Rees CA, Murphy KE. Retrotransposon insertion in SILV is responsible for merle patterning of the domestic dog. Proc Natl Acad Sci U S A. 103(5):1376-1381 (2006). Kaelin CB, Barsh GS. Genetics of pigmentation in dogs and cats. Annu. Rev. Anim. Biosci. 1:16.1-16.32 (2013).

5

THE MERLE CONTROVERSY AND AKC BULLDOGS (ENGLISH BULLDOGS)

We use UC Davis for our MERLE Testing

https://www.vgl.ucdavis.edu/services/dog/Merle.php

Hidden Merle Facts

Merle can be hidden by other genes, and patterns, sometimes for long periods of time. This is why the merle gene can and has ALWAYS been in EVERY breed and is backed up by scientific fact.

3. The greying gene can also make it very difficult to see merle markings.

4. The dilution gene (dd), can also hide the merle because it dilutes the patches to roughly the same color as the base.

5. Brindle: Merle can be very difficult to see on a brindle too, due to the stripes. Brindle can hide merle, merle can hide brindle, or they can mix.

6. Heavy Markings: Merle can be hidden if the dog has very heavy markings, so a black merle could appear completely black if the patches are large enough (a cryptic merle).

Partial Excerpt from the UCDavis Website

https://www.vgl.ucdavis.edu/services/dog/Merle.php

Merle is an incompletely dominant coat color pattern characterized by irregularly shaped patches of diluted pigment and solid color.

Dogs with cryptic merle (also called phantom or ghost merle), typically display little to no merling and some may be misclassified as non-merles.

The Veterinary Genetics Laboratory is licensed to offer the merle test.

Results are reported as:

M/M 2 copies of merle are present (double merle)

M/Mc 1 copy of merle and 1 copy of cryptic merle are present

M/N 1 copy of merle is present

Mc/Mc 2 copies of cryptic merle are present

Mc/N 1 copy of cryptic merle is present

N/N No copies of merle or cryptic merle are present

6

THE MERLE CONTROVERSY AND AKC BULLDOGS (ENGLISH BULLDOGS)

We use UC Davis for our MERLE Testing

https://www.vgl.ucdavis.edu/services/dog/Merle.php

Hidden Merle Facts

Merle can be hidden by other genes, and patterns, sometimes for long periods of time. This is why the merle gene can and has ALWAYS been in EVERY breed and is backed up by scientific fact.

3. The greying gene can also make it very difficult to see merle markings.

4. The dilution gene (dd), can also hide the merle because it dilutes the patches to roughly the same color as the base.

5. Brindle: Merle can be very difficult to see on a brindle too, due to the stripes. Brindle can hide merle, merle can hide brindle, or they can mix.

6. Heavy Markings: Merle can be hidden if the dog has very heavy markings, so a black merle could appear completely black if the patches are large enough (a cryptic merle).

Partial Excerpt from the UCDavis Website

https://www.vgl.ucdavis.edu/services/dog/Merle.php

Merle is an incompletely dominant coat color pattern characterized by irregularly shaped patches of diluted pigment and solid color.

Dogs with cryptic merle (also called phantom or ghost merle), typically display little to no merling and some may be misclassified as non-merles.

The Veterinary Genetics Laboratory is licensed to offer the merle test.

Results are reported as:

M/M 2 copies of merle are present (double merle)

M/Mc 1 copy of merle and 1 copy of cryptic merle are present

M/N 1 copy of merle is present

Mc/Mc 2 copies of cryptic merle are present

Mc/N 1 copy of cryptic merle is present

N/N No copies of merle or cryptic merle are present

7

THE MERLE CONTROVERSY AND AKC BULLDOGS (ENGLISH BULLDOGS)

We use UC Davis for our MERLE Testing

https://www.vgl.ucdavis.edu/services/dog/Merle.php

Hidden Merle Facts

Merle can be hidden by other genes, and patterns, sometimes for long periods of time. This is why the merle gene can and has ALWAYS been in EVERY breed and is backed up by scientific fact.

3. The greying gene can also make it very difficult to see merle markings.

4. The dilution gene (dd), can also hide the merle because it dilutes the patches to roughly the same color as the base.

5. Brindle: Merle can be very difficult to see on a brindle too, due to the stripes. Brindle can hide merle, merle can hide brindle, or they can mix.

6. Heavy Markings: Merle can be hidden if the dog has very heavy markings, so a black merle could appear completely black if the patches are large enough (a cryptic merle).

Partial Excerpt from the UCDavis Website

https://www.vgl.ucdavis.edu/services/dog/Merle.php

Merle is an incompletely dominant coat color pattern characterized by irregularly shaped patches of diluted pigment and solid color.

Dogs with cryptic merle (also called phantom or ghost merle), typically display little to no merling and some may be misclassified as non-merles.

The Veterinary Genetics Laboratory is licensed to offer the merle test.

Results are reported as:

M/M 2 copies of merle are present (double merle)

M/Mc 1 copy of merle and 1 copy of cryptic merle are present

M/N 1 copy of merle is present

Mc/Mc 2 copies of cryptic merle are present

Mc/N 1 copy of cryptic merle is present

N/N No copies of merle or cryptic merle are present

9

THE MERLE CONTROVERSY AND AKC BULLDOGS (ENGLISH BULLDOGS)

We use UC Davis for our MERLE Testing

https://www.vgl.ucdavis.edu/services/dog/Merle.php

Hidden Merle Facts

Merle can be hidden by other genes, and patterns, sometimes for long periods of time. This is why the merle gene can and has ALWAYS been in EVERY breed and is backed up by scientific fact.

3. The greying gene can also make it very difficult to see merle markings.

4. The dilution gene (dd), can also hide the merle because it dilutes the patches to roughly the same color as the base.

5. Brindle: Merle can be very difficult to see on a brindle too, due to the stripes. Brindle can hide merle, merle can hide brindle, or they can mix.

6. Heavy Markings: Merle can be hidden if the dog has very heavy markings, so a black merle could appear completely black if the patches are large enough (a cryptic merle).

Partial Excerpt from the UCDavis Website

https://www.vgl.ucdavis.edu/services/dog/Merle.php

Merle is an incompletely dominant coat color pattern characterized by irregularly shaped patches of diluted pigment and solid color.

Dogs with cryptic merle (also called phantom or ghost merle), typically display little to no merling and some may be misclassified as non-merles.

The Veterinary Genetics Laboratory is licensed to offer the merle test.

Results are reported as:

M/M 2 copies of merle are present (double merle)

M/Mc 1 copy of merle and 1 copy of cryptic merle are present

M/N 1 copy of merle is present

Mc/Mc 2 copies of cryptic merle are present

Mc/N 1 copy of cryptic merle is present

N/N No copies of merle or cryptic merle are present

10

THE MERLE CONTROVERSY AND AKC BULLDOGS (ENGLISH BULLDOGS)

We use UC Davis for our MERLE Testing

https://www.vgl.ucdavis.edu/services/dog/Merle.php

Hidden Merle Facts

Merle can be hidden by other genes, and patterns, sometimes for long periods of time. This is why the merle gene can and has ALWAYS been in EVERY breed and is backed up by scientific fact.

3. The greying gene can also make it very difficult to see merle markings.

4. The dilution gene (dd), can also hide the merle because it dilutes the patches to roughly the same color as the base.

5. Brindle: Merle can be very difficult to see on a brindle too, due to the stripes. Brindle can hide merle, merle can hide brindle, or they can mix.

6. Heavy Markings: Merle can be hidden if the dog has very heavy markings, so a black merle could appear completely black if the patches are large enough (a cryptic merle).

Partial Excerpt from the UCDavis Website

https://www.vgl.ucdavis.edu/services/dog/Merle.php

Merle is an incompletely dominant coat color pattern characterized by irregularly shaped patches of diluted pigment and solid color.

Dogs with cryptic merle (also called phantom or ghost merle), typically display little to no merling and some may be misclassified as non-merles.

The Veterinary Genetics Laboratory is licensed to offer the merle test.

Results are reported as:

M/M 2 copies of merle are present (double merle)

M/Mc 1 copy of merle and 1 copy of cryptic merle are present

M/N 1 copy of merle is present

Mc/Mc 2 copies of cryptic merle are present

Mc/N 1 copy of cryptic merle is present

N/N No copies of merle or cryptic merle are present

12

THE MERLE CONTROVERSY AND AKC BULLDOGS (ENGLISH BULLDOGS)

We use UC Davis for our MERLE Testing

https://www.vgl.ucdavis.edu/services/dog/Merle.php

Hidden Merle Facts

Merle can be hidden by other genes, and patterns, sometimes for long periods of time. This is why the merle gene can and has ALWAYS been in EVERY breed and is backed up by scientific fact.

3. The greying gene can also make it very difficult to see merle markings.

4. The dilution gene (dd), can also hide the merle because it dilutes the patches to roughly the same color as the base.

5. Brindle: Merle can be very difficult to see on a brindle too, due to the stripes. Brindle can hide merle, merle can hide brindle, or they can mix.

6. Heavy Markings: Merle can be hidden if the dog has very heavy markings, so a black merle could appear completely black if the patches are large enough (a cryptic merle).

Partial Excerpt from the UCDavis Website

https://www.vgl.ucdavis.edu/services/dog/Merle.php

Merle is an incompletely dominant coat color pattern characterized by irregularly shaped patches of diluted pigment and solid color.

Dogs with cryptic merle (also called phantom or ghost merle), typically display little to no merling and some may be misclassified as non-merles.

The Veterinary Genetics Laboratory is licensed to offer the merle test.

Results are reported as:

M/M 2 copies of merle are present (double merle)

M/Mc 1 copy of merle and 1 copy of cryptic merle are present

M/N 1 copy of merle is present

Mc/Mc 2 copies of cryptic merle are present

Mc/N 1 copy of cryptic merle is present

N/N No copies of merle or cryptic merle are present

13

THE MERLE CONTROVERSY AND AKC BULLDOGS (ENGLISH BULLDOGS)

We use UC Davis for our MERLE Testing

https://www.vgl.ucdavis.edu/services/dog/Merle.php

Hidden Merle Facts

Merle can be hidden by other genes, and patterns, sometimes for long periods of time. This is why the merle gene can and has ALWAYS been in EVERY breed and is backed up by scientific fact.

3. The greying gene can also make it very difficult to see merle markings.

4. The dilution gene (dd), can also hide the merle because it dilutes the patches to roughly the same color as the base.

5. Brindle: Merle can be very difficult to see on a brindle too, due to the stripes. Brindle can hide merle, merle can hide brindle, or they can mix.

6. Heavy Markings: Merle can be hidden if the dog has very heavy markings, so a black merle could appear completely black if the patches are large enough (a cryptic merle).

Partial Excerpt from the UCDavis Website

https://www.vgl.ucdavis.edu/services/dog/Merle.php

Merle is an incompletely dominant coat color pattern characterized by irregularly shaped patches of diluted pigment and solid color.

Dogs with cryptic merle (also called phantom or ghost merle), typically display little to no merling and some may be misclassified as non-merles.

The Veterinary Genetics Laboratory is licensed to offer the merle test.

Results are reported as:

M/M 2 copies of merle are present (double merle)

M/Mc 1 copy of merle and 1 copy of cryptic merle are present

M/N 1 copy of merle is present

Mc/Mc 2 copies of cryptic merle are present

Mc/N 1 copy of cryptic merle is present

N/N No copies of merle or cryptic merle are present

14

THE MERLE CONTROVERSY AND AKC BULLDOGS (ENGLISH BULLDOGS)

We use UC Davis for our MERLE Testing

https://www.vgl.ucdavis.edu/services/dog/Merle.php

Hidden Merle Facts

Merle can be hidden by other genes, and patterns, sometimes for long periods of time. This is why the merle gene can and has ALWAYS been in EVERY breed and is backed up by scientific fact.

3. The greying gene can also make it very difficult to see merle markings.

4. The dilution gene (dd), can also hide the merle because it dilutes the patches to roughly the same color as the base.

5. Brindle: Merle can be very difficult to see on a brindle too, due to the stripes. Brindle can hide merle, merle can hide brindle, or they can mix.

6. Heavy Markings: Merle can be hidden if the dog has very heavy markings, so a black merle could appear completely black if the patches are large enough (a cryptic merle).

Partial Excerpt from the UCDavis Website

https://www.vgl.ucdavis.edu/services/dog/Merle.php

Merle is an incompletely dominant coat color pattern characterized by irregularly shaped patches of diluted pigment and solid color.

Dogs with cryptic merle (also called phantom or ghost merle), typically display little to no merling and some may be misclassified as non-merles.

The Veterinary Genetics Laboratory is licensed to offer the merle test.

Results are reported as:

M/M 2 copies of merle are present (double merle)

M/Mc 1 copy of merle and 1 copy of cryptic merle are present

M/N 1 copy of merle is present

Mc/Mc 2 copies of cryptic merle are present

Mc/N 1 copy of cryptic merle is present

N/N No copies of merle or cryptic merle are present

15

THE MERLE CONTROVERSY AND AKC BULLDOGS (ENGLISH BULLDOGS)

We use UC Davis for our MERLE Testing

https://www.vgl.ucdavis.edu/services/dog/Merle.php

Hidden Merle Facts

Merle can be hidden by other genes, and patterns, sometimes for long periods of time. This is why the merle gene can and has ALWAYS been in EVERY breed and is backed up by scientific fact.

3. The greying gene can also make it very difficult to see merle markings.

4. The dilution gene (dd), can also hide the merle because it dilutes the patches to roughly the same color as the base.

5. Brindle: Merle can be very difficult to see on a brindle too, due to the stripes. Brindle can hide merle, merle can hide brindle, or they can mix.

6. Heavy Markings: Merle can be hidden if the dog has very heavy markings, so a black merle could appear completely black if the patches are large enough (a cryptic merle).

Partial Excerpt from the UCDavis Website

https://www.vgl.ucdavis.edu/services/dog/Merle.php

Merle is an incompletely dominant coat color pattern characterized by irregularly shaped patches of diluted pigment and solid color.

Dogs with cryptic merle (also called phantom or ghost merle), typically display little to no merling and some may be misclassified as non-merles.

The Veterinary Genetics Laboratory is licensed to offer the merle test.

Results are reported as:

M/M 2 copies of merle are present (double merle)

M/Mc 1 copy of merle and 1 copy of cryptic merle are present

M/N 1 copy of merle is present

Mc/Mc 2 copies of cryptic merle are present

Mc/N 1 copy of cryptic merle is present

N/N No copies of merle or cryptic merle are present

16

THE MERLE CONTROVERSY AND AKC BULLDOGS (ENGLISH BULLDOGS)

We use UC Davis for our MERLE Testing

https://www.vgl.ucdavis.edu/services/dog/Merle.php

Hidden Merle Facts

Merle can be hidden by other genes, and patterns, sometimes for long periods of time. This is why the merle gene can and has ALWAYS been in EVERY breed and is backed up by scientific fact.

3. The greying gene can also make it very difficult to see merle markings.

4. The dilution gene (dd), can also hide the merle because it dilutes the patches to roughly the same color as the base.

5. Brindle: Merle can be very difficult to see on a brindle too, due to the stripes. Brindle can hide merle, merle can hide brindle, or they can mix.

6. Heavy Markings: Merle can be hidden if the dog has very heavy markings, so a black merle could appear completely black if the patches are large enough (a cryptic merle).

Partial Excerpt from the UCDavis Website

https://www.vgl.ucdavis.edu/services/dog/Merle.php

Merle is an incompletely dominant coat color pattern characterized by irregularly shaped patches of diluted pigment and solid color.

Dogs with cryptic merle (also called phantom or ghost merle), typically display little to no merling and some may be misclassified as non-merles.

The Veterinary Genetics Laboratory is licensed to offer the merle test.

Results are reported as:

M/M 2 copies of merle are present (double merle)

M/Mc 1 copy of merle and 1 copy of cryptic merle are present

M/N 1 copy of merle is present

Mc/Mc 2 copies of cryptic merle are present

Mc/N 1 copy of cryptic merle is present

N/N No copies of merle or cryptic merle are present

17

THE MERLE CONTROVERSY AND AKC BULLDOGS (ENGLISH BULLDOGS)

We use UC Davis for our MERLE Testing

https://www.vgl.ucdavis.edu/services/dog/Merle.php

Hidden Merle Facts

Merle can be hidden by other genes, and patterns, sometimes for long periods of time. This is why the merle gene can and has ALWAYS been in EVERY breed and is backed up by scientific fact.

3. The greying gene can also make it very difficult to see merle markings.

4. The dilution gene (dd), can also hide the merle because it dilutes the patches to roughly the same color as the base.

5. Brindle: Merle can be very difficult to see on a brindle too, due to the stripes. Brindle can hide merle, merle can hide brindle, or they can mix.

6. Heavy Markings: Merle can be hidden if the dog has very heavy markings, so a black merle could appear completely black if the patches are large enough (a cryptic merle).

Partial Excerpt from the UCDavis Website

https://www.vgl.ucdavis.edu/services/dog/Merle.php

Merle is an incompletely dominant coat color pattern characterized by irregularly shaped patches of diluted pigment and solid color.

Dogs with cryptic merle (also called phantom or ghost merle), typically display little to no merling and some may be misclassified as non-merles.

The Veterinary Genetics Laboratory is licensed to offer the merle test.

Results are reported as:

M/M 2 copies of merle are present (double merle)

M/Mc 1 copy of merle and 1 copy of cryptic merle are present

M/N 1 copy of merle is present

Mc/Mc 2 copies of cryptic merle are present

Mc/N 1 copy of cryptic merle is present

N/N No copies of merle or cryptic merle are present

ON THIS PAGE

COLOR GENETICS BASICS

LETS GET STARTED. LESSON 1A

LESSON 1B

LESSON 1C

LESSON 1D

COLOR GENETICS BASICS Lesson 2

LESSON 2A

LESSON 2B

LESSON 2C

COLOR DNA TESTING

Introduction

DNA Q & A

TESTING CENTERS

HEALTH DNA

HEALTH DNA INFO AND TESTING

DM...ENGLISH & FRENCH BULLDOGS

HUU...ENGLISH & FRENCH BULLDOGS

CMR1...ENGLISH & FRENCH BULLDOGS

HC...FRENCH BULLDOGS

INBREEDING COEFFICIENT

FRENCH BULLDOG CHOCOLATE

THE FRENCH BULLDOG AND CHOCOLATE COLOR

TESTABLE VS NON TESTABLE CHOCOLATE

Contributions from experienced Breeders

RICK PEZ

JOYCE WILD

JOYCE WILD

HERIN CHIN

SCIENCE DON'T LIE! HERSHEY'S DNA FOR COLOR AND PARENTAGE

NORMAL CHOCOLATE LITTER BY JOYCE WILD + DNA

THE FRENCH BULLDOG AND RED EYE GLOW

4

THE MERLE CONTROVERSY AND AKC BULLDOGS (ENGLISH BULLDOGS)

We use UC Davis for our MERLE Testing

Hidden Merle Facts

Partial Excerpt from the UCDavis Website

5

THE MERLE CONTROVERSY AND AKC BULLDOGS (ENGLISH BULLDOGS)

We use UC Davis for our MERLE Testing

Hidden Merle Facts

Partial Excerpt from the UCDavis Website

6

THE MERLE CONTROVERSY AND AKC BULLDOGS (ENGLISH BULLDOGS)

We use UC Davis for our MERLE Testing

Hidden Merle Facts

Partial Excerpt from the UCDavis Website

7

THE MERLE CONTROVERSY AND AKC BULLDOGS (ENGLISH BULLDOGS)

We use UC Davis for our MERLE Testing

Hidden Merle Facts

Partial Excerpt from the UCDavis Website

9

THE MERLE CONTROVERSY AND AKC BULLDOGS (ENGLISH BULLDOGS)

We use UC Davis for our MERLE Testing

Hidden Merle Facts

Partial Excerpt from the UCDavis Website

10

THE MERLE CONTROVERSY AND AKC BULLDOGS (ENGLISH BULLDOGS)

We use UC Davis for our MERLE Testing

Hidden Merle Facts

Partial Excerpt from the UCDavis Website

12

THE MERLE CONTROVERSY AND AKC BULLDOGS (ENGLISH BULLDOGS)

We use UC Davis for our MERLE Testing

Hidden Merle Facts

Partial Excerpt from the UCDavis Website

13

THE MERLE CONTROVERSY AND AKC BULLDOGS (ENGLISH BULLDOGS)

We use UC Davis for our MERLE Testing

Hidden Merle Facts

Partial Excerpt from the UCDavis Website

14

THE MERLE CONTROVERSY AND AKC BULLDOGS (ENGLISH BULLDOGS)

We use UC Davis for our MERLE Testing

Hidden Merle Facts

Partial Excerpt from the UCDavis Website

15

THE MERLE CONTROVERSY AND AKC BULLDOGS (ENGLISH BULLDOGS)

We use UC Davis for our MERLE Testing