Why is it a dangerous practice?

Have a look at these dogs:

What colour do you think that they are?

Would it surprise you to learn that both of these dogs are merle?  The one on the left is genetically a red merle, the one on the right a blue merle.

One of the biggest concerns that has been expressed over the crossing of Pembrokes with merles from other breeds, is that there could be merle genes being carried without the breeders knowledge.   The proponents of this type of crossbreeding assure that they can always identify merle puppies!  Again this is not true!

Puppy #1 (Pembroke and Cardigan Cross)

Here are photos of puppy #1 from birth to adult. At birth you can see that this puppy is a Red Merle, however as he grew the merle pattern grew less distinct, until as a adult he presents as what would be called a red in Cardigans. The only remaining hint to his true genetic makeup is a small patch of merle behind the ear, and his blue eyes.   Since we don’t breed them when they are newborn, had he not been neutered, any unwitting person could have bred this dog later in life assuming the breeding would be safe from the deafness and blindness issues associated with a double merle breeding.

Puppy #2 (Purebred Cardigan)

This dog was bred by a reputable breeder. Furthermore, this dog was bred by doing an allowable breeding of a black sire, and a blue merle dam.  His blue eyes are the only visible sign of  merle.

So what happened?

The E-locus (Clear Red ee gene)

In Cardigan Corgis breeders deal with another gene that purebred Pembroke corgis don’t need to worry about.  In Cardigan breeding throughout history, we knew that certain colour combinatons had specific percentage probabilities of producing certain colours.   The most consistent of these were that if you bred and black with red or brindle points to a blue merle the only two colours you should get are black and blue merle.

But every so often a “red” would pop up when it wasn’t expected.

In 1992, a litter appeared that were all varying shades of this light red.   However, since the breed standard allowed showing red (all shades) these puppies were registered as red, but those in the breed called  them “pinks”

Here is a Clear red puppy with her normal red and brindle littermates in 1999.   The colour pedigree on this litter is below.   The two great-great-grandparents who are suspected in carrying the gene for this light red colour are indicated in red.  This indicates just how long this recessive gene carried through a pedigree without displaying itself.

Brindle and White 1999	Brindle and White 1996	Brindle and White 1989	Brindle and White 1982
			Suspected “Ee” Carrier Brindle and White 1986
		Red and White 1991	Brindle and White 1989
			Brindle and White 1988
	Brindle and White 1995	Brindle and White 1990	Red and White 1981
			Brindle and White 1985
		Red and White 1992	Red and White 1981
			Suspected “Ee” Carrier Red and White 1989

This colour began to pop up unexpectedly more and more frequently, and finally it was determined by Dr. Sheila Schmutz at the University of Saskatchewan, that this colouration was the result of the e/e locus.  Her research into colour genetics is documented on her website – “Genetics of Coat Colour and Type in Dogs”.

To quote from the website:

“This gene has two common alleles E and e. Dogs that are e/e are red or yellow due to phaeomelanin production, and this is the recessive genotype. When E is present in a dog, it usually has some black or brown in its coat because of the production of eumelanin. The E allele is dominant to the e allele.

Although the e/e genotype is the most recessive at this locus, it is epistatic or masks other genotypes at other loci, such as the K and A locus. See more about those loci on separate pages.”

In layman’s terms, the presence of the e/e  locus hides black, red, sable and brindle and merle coat colourations.

In other breeds where merle is not an issue, carrrying the e/e combination is not at all an issue.  Yellow Labrador Retrievers are e/e.   A full list of breeds that carry e/e is available on her site “The E Locus in Dogs.”

In Cardigans it was called “Clear Red”, and it masks the ability to show black.  We now knew what these formerly “Pink” puppies were!   They were blacks, blues, brindles or reds, where the colour was hidden.

What is the issue is the ability of the gene to mask Merle (the K Locus).  On the Merle page is a photo of a Chihuahua named “Mellow”.  Although Merle to Merle breedings are frowned up because of the Deafness & Blindness issues, Mellow was the product of a Merle to Merle breeding – and yet he presents as a cream or biscuit colour although by  his double merle parentage he MUST be Merle.  This issue is not only in Cardigans, but also Chihuahuas, Pomeranians, Dobermans, and others.

You can see from these examples why a combination of genetic testing, and informed, knowledgeable and ethical breeding practices are important.   Hopefully, this has been explained in such a way that it makes sense to the average pet buyer.  Should you have any questions please contact us by Facebook at “Blue Merle Pembroke Corgis – The Truth About Cardigan/Pembroke Crosses” or by the contact form on this website.