Our friends the Merle Australian Shepherds are not the only dogs who are an intersection of two different lethal semi-dominant alleles; Harlequin Great Danes share this problematic status as both the merle gene and the harlequin gene are lethal in the homozygous state.
The result of a Harlequin x Harlequin breeding is 7 lethal : 5 undesirable : 4 Harlequin. Unlike our non-bobtail Aussies, the Danes’ coats can’t be corrected at birth, so you can’t mask the just slightly undesirable outcomes (like docking a natural tail that didn’t get the bobtail gene). That means that if we really really want Harlequins, the best we’re going to get is 25% of potential puppies and less than half of the otherwise healthy ones that are born matching their parents in phenotype.
Great Dane graphics provided courtesy of Cartoonize My Pet.
The red dogs in the upper left are knocked out due to the lethality of the Harlequin gene in the homozygous state. In addition to the upper left dog, the three pink dogs are double merles and that is also a lethal situation but apparently not as fatal as Harlequin. We wouldn’t expect these dogs to be born in the theoretical numbers as some will be prenatal lethal and some of those that are born will have problems with vision and hearing.
The yellow backed dogs are simply undesirable phenotypes that necessarily occur when trying to breed Harlequin as neither Harlequin nor Merle breed true being lethal in the homozygous form. We will always have mantle (no merle, no harlequin); merle (merle, no harlequin); merlequin (double merle, no harlequin); and white (double merle, harlequin) dogs in any breeding program that breeds phenotypically harlequin dogs together. Pheotypically Harlequin dogs are HhMm, a double heterozygote.
The dogs referred to as Merlequin are actually hhMM, meaning they don’t carry the harlequin allele at all and are in fact double merles. The name is a misnomer and the dogs themselves are subject the the same genetic challenges as double merles in other breeds.
Merlequin dogs can suffer from blindess, deafness, neurological problems, skin disorders, and other autoimmune problems.
Merlequin dogs can be completely avoided by breeding Harlequin (HhMm) to Mantle (*hmm), and not breeding Harlequin to any merle dog or another Harley.
The dogs referred to as White are HhMM, double merle harlequins. The addition of one copy of the Harlequin allele has been shown to increase both the prenatal lethality and increase impairment in viable puppies. Despite making the double merle puppies even less likely to reach term, there are still plenty of these White dogs born; so much so that numerous rescue groups exist to rehome the blind, deaf, and otherwise diseased white Danes.
In addition to the bleaching effects of the Harlequin and Merle genes, Danes also carry the genes for Irish spotting and piebald. This full platter of genes can combine to create dogs with very little color on them and a host of color related issues:
Congential cataracts, micropthalmia, persistant pupullary membrane, tapetal hypoplasia, convergent stabismus, entropthalmia, medical canthal syndrome, heterochromia iridis, hyperchromia iridis, colomboma, merle deafness, piebald deafness, demodicosis, atopic dermatitis, skin cancer, follicular dysplasia, photo-induced epilepsy, sterilty, reduced fertility, smaller litter sizes, failure to thrive, and social instability.
Unlike my fictional scenario for the “wild” Australian Shepherd were I assumed that the majority of breeders were carefully selecting against doubling up on two lethal traits and that left to their own devices the dogs would seek to maximize the expression of merle and bobtail on their own, the Great Dane Club of America not only permits the breeding of Harlequin to Harlequin, they don’t find this practice a breach of their Code of Ethics and virtually guarantee more of it given their enforcement of color families within the Dane breed.
The GDCA Code of Ethics states:
ALL BREEDERS AND OWNERS OF GREAT DANES (BITCHES AND STUD DOGS ALIKE) SHALL:
- Breed Great Danes which are temperamentally and structurally sound.
- Be familiar with the Breed Standard and breed only those dogs and bitches which most closely conform to it.
- Keep well informed in the field of genetics and work to eliminate hereditary defects from the breed.
- Refrain from further use of a Great Dane for breeding if the dog or bitch has produced any offspring with serious inherited defects detrimental to an animal’s well being (physically or mentally), and has produced like results with a different mating partner.
Notice that the first ethic fails to address physical soundness entirely, which would include breeding blind and deaf dogs. Blindness, deafness, and especially neurological problems only exacerbate issues of temperament, and yet Great Dane breeders regularly breed against this ethic.
The third ethic demands that breeders both know about genetics and also eliminate hereditary defects from the breed. Blindness is a hereditary defect. Deafness is a hereditary defect. Every single color related complication in that massive list above is a hereditary defect. And yet the breeding schemes which produce and exacerbate these hereditary defects are not outlawed in specific by the GDCA. Apparently there’s an unwritten rule that you can violate the Code of Ethics as long as it’s for aesthetic reasons.
The fourth ethic is even more harsh. It demands that breeders should abandon breeding stock that has produced physically or mentally defective offspring. Any sane human would agree that this must include the production of dogs that are blind, deaf, or have neurological defects. Do we have any evidence that the club has forced any dog into retirement over creating blind, deaf, and otherwise diseased offspring?
The GDCA even endorses a “Breeder’s Color Code” which on the outside one might guess would ban the breeding of Harlequin to Harlequin like the parent club of the breed in the country of origin did, the German Deutscher Doggen Club. No, in fact, their Color Code essentially breaks the breed up into four individual breeds that should not be crossbred.
Color Classifications being well founded, the Great Dane Club of America, Inc. considers it an inadvisable practice to mix color strains and it is the club’s policy to be cognizant of the following breedings:
|Color of Dane||Approved Breedings||Desired Pedigrees|
|1. FAWN1. BRINDLE||1. FAWN bred to FAWN or BRINDLE only.
1. BRINDLE bred to BRINDLE or FAWN only.
|Pedigrees of FAWN or BRINDLE Danes should not carry BLACK, HARLEQUIN or BLUE upon them.|
|2. HARLEQUIN2. MANTLE2. BLACK (HARLEQUIN BRED)||2. HARLEQUIN bred to HARLEQUIN, BLACK from HARLEQUIN BREEDING or BLACK from BLACK BREEDING only.
2. MANTLE bred to HARLEQUIN, MANTLE, BLACK from HARLEQUIN breeding or BLACK from BLACK breeding only.
2. BLACK from HARLEQUIN BREEDING bred to HARLEQUIN, BLACK from HARLEQUIN BREEDING or BLACK from BLACK BREEDING only.
|Pedigrees of HARLEQUIN, MANTLE or HARLEQUIN BRED BLACK Danes should not carry FAWN, BRINDLE or BLUE upon them.|
|3. BLUE3. BLACK (BLUE BRED)||3. BLUE bred to BLUE, BLACK from BLUE BREEDING or BLACK from BLACK BREEDING only.
3. BLACK from BLUE BREEDING bred to BLUE, BLACK from BLUE BREEDING or BLACK from BLACK BREEDING ONLY.
|Pedigrees of BLUE or BLUE BRED BLACK Danes should notcarry FAWN, BRINDLE, or HARLEQUIN upon them.|
|4. BLACK (BLACK BRED)||4. BLACK from BLACK BREEDING bred to BLACK, BLUE or HARLEQUIN and MANTLE. (See note below)||Pedigrees of BLACK BRED Danes should not carry FAWN, BRINDLE, HARLEQUIN, MANTLE or BLUE upon them.|
Since the claim is often made that it’s only the “Backyard Breeder” or “puppymill” that creates intentionally bred double merles or white dogs, let us investigate the pedigree of the highest ranking Harlequin Great Dane show dog in the country right now.
There’s only one Harlequin Great Dane in the top 10 show dogs, and his name is GCH CH Drd’s The Revelation. This is his advertisement.
This dog does not appear to be a double merle or have anything wrong with his eyes. In fact, he’s not the product of a Harlequin x Harlequin or Harlequin x Merle mating. A good start, for sure. But let’s look at his pedigree and see how this dog came to be:
Out of the most recent 15 breedings that produced our Harlequin, 6 of them were Harlequin to Harlequin. There is no test, no magic technique that could have been used in any of those breedings to prevent the creation of lethal double harls, double merles, and whites; all of which could be severely incapacitated with inbred disease.
Some of the dogs used in this pedigree might have even been HhMM Whites. Judge for yourself.
Perhaps the most famous Harlequin Great Dane in recent memory is “Rumpus” who starred with his mother “Lava” in several Lady Gaga music videos including Poker Face, Love Game, and Paparazzi. Rumpus was only 5 years old when he died after a hike in the Hollywood Hills.
Rumpus (Ch. PCH Start The Commotion) is actually a cousin to the #1 Harlequin Great Dane, as his grand sire is Sasdania’s Passion Tristan. His mother is the Harlequin on the left of the photo above, Am Int’l Nat’l Ch. PCH It’s What’s Shakin, AOM, OA, AXJ, OJP, OAP, HOF, GDCA-VA CGC TDI TT, and his father is a Harlequin named BIS, BISS Ch. GMJ’s the Five Card Studd pictured below.
So don’t let it be said that Harlequin to Harlequin litters are rare or only the product of ignorant puppy millers or backyard breeders. This dangerous and unnecessary practice is done in the open and at the highest level of the sport. While some of these breeders might choose to kill and dispose of any defective white puppies born from such matings, removing the trace of these dogs from public scrutiny, clearly there are enough breeders who still breed Harlequin to Harlequin and Harlequin to Merle and then farm their defective puppies out into the rescue system.
The frightening thing is that this doesn’t appear to be a rare or even questioned practice within the breeding elite. Rather it seems to be routine, accepted, approved, and even encouraged.
Correction: The GDCA does not approve of Harlequin x Merle breedings as they don’t recognize Merle as an approved color at all.
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