About Merles and the Merle Gene

One dose of the merle gene on an otherwise black dog produces a 
blue merle - a more or less bluish gray dog dappled with black spots. 
Tan points - the tan spots over the eyes, on the sides of the muzzle, on the legs 
and under the tail of a tricolor dog - will still be there in the merled tricolor. 
If the tan spots would not be present in a black dog, tan will not be present 
in the merled black either, and the dog will blue merle and white without tan. 
One dose of the merle gene on an otherwise sable dog produces a sable merle. 
Sable merles are less predictable in color than blue merles, and may range anywhere 
from an apparent sable, often with a pinkish or orange cast to its coat, to something 
that looks like a very rusty blue merle. White markings remain on the merled dog, 
and may even be slightly more prominant. 

Merle acts on the dark pigment in the iris of the eye just as it does on the 
coat, so merle dogs often have part or all of the eye blue. (This does not affect their 
vision, though since it happens to some extent in the retina as well it may 
make it harder to diagnose certain eye problems.)

Notice what was said was a single dose of the merle gene. There are always 
two copies of a gene, alike or different, in any dog. If we call the merle 
gene M and the non-merle gene m, any given dog can be mm, Mm or MM. 
The mm dog is the normal, full-colored tri, bi-color, or sable, or liver (red) in 
Australian Shepherds. The Mm Cocker is a blue merle,  or brown merle, etc,depending on 
what color it would have been without the merling gene. An MM dog, 
often called a double merle or a homozygous merle, will be mostly 
white and sometimes deaf or blind and often with other physical problems. 
Some MM puppies are born completely without eyes.

On average over a large number of litters, breeding merle to merle will produce 
one fourth full colored dogs, one half merles and one fourth defective whites. 
Breeding merle to full color will produce one half full color and one half merles, 
but no defective whites. The merle to full color breeding, then, produces just 
as many merles as does the merle to merle breeding, and without the danger of 
defective puppies. The safe breeding for a merle, then, is to a non-merle mate. 
This breeding should produce all healthy puppies, and about half will be merles. 

To breed in this way, it is important to know which dogs are merles. 
This is one of the reasons experienced breeders rarely 
breed blue merles to sables,
or roans as this mating may produce sable merles or merles to the
inexperienced breeder to appear incorrectly as roans..

Sable merles are no more likely to have health problems than any other color. 
Sometimes you cannot tell a sable is a merle unless you see it on the tips of it's 
ears or the eye or eyes are blue or blue flecked.,. The real arguement 
against sable merles is that they may be mistaken for normal sables. If two such sable
merles were mated together, the resulting litter could contain defective whites.
The sable gene can also mask the merle, and as the dog ages it may be
next to impossible to tell by looking that this IS a merle dog.

There is one kind of breeding that can produce all or almost all merles, and that 
is the breeding of a tricolor or a bi-color to a double merle - but remember that 
the double merle in other breeds, has a high probability of being blind or deaf. 
Very few breeders 
have been lucky enough to get high quality homozygous merles that are not too 
severely affected to breed - but it definitely takes a lot of luck and really top 
quality blue merles to start with. Merle to merle breedings are only for the very 
experienced breeder who knows their lines and what they will produce - and it 
has probably produced more heartbreaks than good homozygous merles, even for them. 
A blue merle from black to homozygous merle breeding is just as healthy 
as one from a more normal black to blue merle breeding. 

Unless you have done a lot of merle breeding and really know what you 
are getting into, the safe rule is still that a merle should be bred 
only to a solid color
With double merles, you would actually have some normal colored hair, 
some diluted hair AND some double 
diluted hair.  Each merle gene would dilute hairs in their own pattern and 
that those patterns might or 
might not overlap.  Therefore you can have 3 different colors of coat 
(normal coat, diluted coat and double diluted "white") coat on 
a genetically SOLID dog!  With parti-colors, the dogs could be almost 
or even entirely white since they already have large 
areas of white. 

Because Cockers have a spotting gene which can leave only small amounts 
of color on the dog, we can't assume that a merle with a lot 
of white is actually a double merle.  A normal, single gene merle parti-color 
dog can have any amount of white that is normal for a 
regular parti-color.  We can have very open-marked merle Cockers and 

It is important to understand that merle is NOT a color, it is a pattern.
  Merle can be compared to painting a room in your house.  Say you paint the room green. 
 Before the paint is allowed to dry, you dip a 
sponge in white paint and then dab the walls with the sponge. 
 For each spot that the sponge touches, you will have a lighter green 
marbling affect that results 
from the green and white paint blending together. 
Merle works in precisely the same fashion. 
The merling can occur on any color. 
A merle black Cocker would leave a black base with a gray marbling affect. 
 A merle brown Cocker would result in a pinkish/tan or cream marbling affect. 

Precisely where the merling chooses to occur is anyone's guess. 
In one litter of puppies, you can have puppies that are merled from nose 
to tail or you can have puppies with nothing more than a merle 
splotch on the top of the head. 
A well merled puppy can go on to produce lightly merled puppies, just as 
a lightly merled puppy has an equal chance of producing heavily merled puppies. 
There is never rhyme nor reason to how the merle gene chooses to act on a puppy. 
There are responsible breeders who have worked to understand the gene 
and how it works. 
They've also put much into their program to produce healthy 
dogs, but, these breeders are far and few between. 
 IRRESPONSIBLE breeders have caused most of the problems.

How does it work?

Merle, as mentioned earlier, is a pattern.  When two Cockers breed, 
they both contribute to each puppy's gene pool.  Have you ever played the card 
game "War"?  In the card game both players are dealt an equal amount of cards.
  Player 'one' flips one card over and Player 'two' flips one card over. 
The player with the highest value card takes both cards 
and puts them in their pile. 
The game continues on until there are no cards left in either player's hand. 
You can compare the genetic make-up of a puppy to a game of "War". 
The dam flips over one gene*, and then the sire flips over one gene. 
The 'higher' valued gene (dominant) goes into the winner's pile. 
The 'lower' valued gene (recessive) goes into the the loser's pile. 
When the game is over, the dominant pile is made up of the genes that
contribute to the 'outside' of a puppy....those things that we see. 
The recessive pile is made up of the genes that contribute to 
the 'inside' of the puppy...those things we can't see. 
When that puppy is old enough to breed, the dominant and 
recessive genes are shuffled and a new game of 'War' begins.

In the card game, you can sometimes have a tie, both players 
flip over the same card of equal value. 
This can also happen with genes in a puppy.  In the card game, 
'War' is declared and there is a 'showdown'.  However dogs have never 
been known to be as competitive as humans are...dogs simply call it a draw.
 It's anyone's guess whose gene (the sire or dam) gets to go in the winner's pile,
but it is really irrelevant, since both genes are identical.

There are thousands of genes involved in the make-up of a dog, from the 
shape of his ears to the length of his tail.  There are approximately 
300 known genes that contribute to coat color/pattern in dogs. 

The gene for merle is dominant over the gene for non merle. 
As an example, we'll say that the sire flips over the merle gene and 
the dam flips over the non merle gene.  The two genes are compared and
the merle gene goes into the winning pile...the part you will see on the puppy. 
The non merle gene will go into the losing pile...the 
part you don't see on the puppy. 
Every time a merle gene is passed on to a puppy, that puppy
will be merle because a merle gene will always be dominant.

*Note:  For those of you that are familiar with genetics, 
I wanted to mention that many times the word 'Gene' is used in 
place of the proper term, "Allele".   I feel that describing alleles will only 
confuse the average viewer and the point can be made by substituting the word 'gene'. 

What is a Double Merle?

If both the sire and the dam of a puppy are merle, they both have an equal 
chance of passing on their dominant merle gene to the puppy. 
The sire may flip over the merle gene, and the dam may flip over the non merle gene. 
 In this case, the sire's merle gene would be dominant and that puppy would be a merle.
 This confuses a lot of people.  How can a merle dog have a non merle gene?
 It is easy to forget that every dog has a winning pile...what you see on the 
outside, and a losing pile...the recessive gene that is hidden.  If each dog only 
had one gene to contribute, there would never be variety in the dogs. 
When two dogs breed, the recessive genes are shuffled with the dominant genes
so that they have a chance to manifest themselves.  If the recessive gene 
meets up with another recessive gene, it finally gets its chance to be in the winning pile.
 However if the recessive gene again meets a dominant gene, it has to wait 
another generation for the chance to dominate. 

It is also possible for both the sire and the dam to flip over their non merle genes.
  If this is the case, it becomes a 'draw' and the puppy is not merle.

And finally, it is possible for both the sire and dam to flip over their merle genes.
  Again, it is a draw, but something totally different happens. 
We'll say that the sire's merle gene gets to go in the winning pile. 
The puppy is now merle.   But the dam also contributed a dominant merle gene. 
Her gene says, "Whoa, wait a minute buddy! 
What do you think this is, the 19th century?
  I demand equal rights here!  I want a chance to merle this puppy and 
the 19th Amendment guarantees me that right!"

So the dam's merle gene goes to work, after the sire's gene has 
already made the puppy merle.  Since it's anybody's guess as to where 
the merle gene will hit (remember the sponge painting earlier?), 
the outcome will vary greatly. We'll assume, for ease of understanding, 
that the sire merled the tail, and nothing more. 
The rest of the puppy was a normal color and untouched by the merle. 
The dam's gene is mad at almost missing out on her chance, 
so she merles the entire body...from head to tail.  The areas that the
sire's merle gene left untouched would now be merled by the dam's merle gene. 
However, the area that the sire's gene did merle (the tail) would be merled again.

Let's go back to the paint.  You finished the first coat of green and then 
finished sponging white paint over the wet green paint. 
Now dip the sponge in the white paint again.  What do you think will 
happen when you start sponging the walls again?  The areas that 
did not get touched by the first sponging, would now have the marbled look, 
but the areas that were marbled the first time would now appear totally white.
This is precisely what happens when the merle 
gene is allowed to act twice on the same area. 
 

So, What's Wrong with a Double Merle?

For reasons unknown, the combination of two merle genes hitting 
the same area of the dog can be lethal. I have seen double merle puppies 
born with no eyes, and/or no ears.   Blindness and/or deafness is also caused 
by the double merle gene.  On the other hand, a double merle can be born
with no deformities at all.

There are no facts or figures available (that I have found) that tells us how many
dogs like this dog have been whelped.  The double merle pattern is an acceptable
pattern in some breeds that is recognized by AKC.   In my opinion, if AKC 
continues to allow this pattern (which can only be achieved by breeding two 
merles together, so it is totally preventable) to be recognized, then serious 
studies should be done to look at the damage being done to the dogs. 

Why Would Anyone Do This?

For every deformed double merle, there is a different excuse. 
Here are a few of those 'excuses' and a few solutions.

1.  Simple ignorance:  Genetics are a complicated matter and many breeders 
won't even take the time to try to learn. 

     Solution:  TAKE THE TIME TO LEARN! 
There are two foundation books on genetics.
 Both  are excellent books but both are out of print.  Try your local library! 

   "Genetics of the Dog:  Malcolm Willis"

   " Inheritance of Coat Color in Dog:  Clarence Cook Little"

2.  Genetic background unknown:  Although the only way to get a double
merle is to breed two merles together, there are many people that don't 
know they own a merle..since AKC has only allowed and 
has ENCOURAGED 
breeders to register their merle cockers as ROAN, it can be very dangerous 
and heartbreaking for those who are uninformed about merle.

     a.  Some merled dogs often fade as they get older.  A dog that was poorly merled 
at birth, and is sable or some other lighter color, will probably
not be recognized as a merle later in life. 

     Solution:  Don't breed lighter colors or sables to merles.
If you do, make sure you YOU UNDERSTAND genetics and the merle gene and how it works,
AND BE ABSOLUTELY SURE to examine every puppy from head to toe at birth. 
This is when the merling is most noticeable.
Be sure to mark a puppy as a merle, 
even if it has no hint of merle at 
eight weeks of age. CHECK the eyes!
If the eye or eyes are a lighter blue than normal puppy blue eyes, or have specks of blue in 
them..be safe and consider this dog a merle!

     b.  Other colors of merles are often so lightly merled, they are not 
marked as merle on their papers.In the case of Cockers, again many breeders 
are registering them as Roans, and every effort
MUST be made to get ASC to allow the merle pattern so AKC can register these dogs as merle.

     Solution:  Again, be sure to record merles at birth. 
A good sign of a merle (assuming one of the parents was a merle) is if 
a puppy has any blue flecks in the eyes.  The merle pattern can color the
iris of the eyes, just as it covers the color of the coat.  When the merle 
pattern hits the iris, it turns it blue, like that of a Siberian Husky. 
Since the merle pattern is so sporadic, it can hit just a spot on the eye,
causing a normal color eye with a tiny blue fleck.   Always mark blue eyed or 
partial blue eyed pups as merle if there is 
even the slightest chance that it is a merle. 
 

     Solution:  If you aren't sure if your dog is double merle, look at the pedigree!
and KNOW THE BREEDER your dogs came from and ask them! Make sure 
the dog is a merle and not called a roan .A double merle will always have a 
merle dam and a merle sire.  ONLY TWO MERLES can produce a double merle. 
The ultimate test of a double merle is to breed it to a SOLID colored dog. 
If ALL the puppies are merle, your dog is a double merle!

GET ON THE BANDWAGON AND CONVINCE THE AMERICAN 
SPANIEL CLUB AND/OR AKC TO GET THESE DOGS LISTED 
AS MERLES AND NOT ROANS OR Some Other color without adding the merle pattern!!!!
 
 

3.  Greed:  If we go back to the genetics behind a double merle, you 
will remember that a double merle results when two merles both 
contribute their merle gene to one puppy.  That puppy, if he goes on to breed,
will have two merle genes that will be shuffled and 
eventually dealt out into the gene pool.
 Since the merle gene is  an incomplete dominant, and the only thing that puppy has is a
merle gene, there is a 100% chance that every, single 
puppy that dog produces will be a merle. 

In other words, a double merle will ALWAYS produce merle puppies, even 
when bred to a normal color dog (black & tan, chocolate & tan, etc.).
 Since merle puppies can command a higher price, due to it being
"RARE", there are breeders who purposely breed merle to merle,
in hopes of getting a double merle.  That double merle can then be 
used to produce all merle puppies...all of his life.  It is interesting to note,
that even a dog which is totally blind and deaf will NEVER produce a deaf
or blind puppy (providing that he isn't bred to another merle or carrying
some other genetic defect that causes deafness/blindness). 
The deafness/blindness seen in double merle is 
only a result of the two merle genes.

Solution:  There is no solution for this sort of breeder. 
Greed is more powerful than compassion.

How Can I Help?

The double merle deformities are not seen just in Cockers. 
As I mentioned earlier, the pattern is seen in several other breeds of dogs. 

Getting the word our about irresponsible breeding of merles is important. 
Many of you are in large cities where you have the ability to get the
word out about the possible dangers of double merle breeding. 
Many of you attend dog shows regularly and can pass out literature
(feel free to print this article) to people at the show. 
Something as simple as scanning the internet for breeders 
selling double merles and sending them the link to this article, 
can go a long way to educate a lot of people.