Dachshund Double Dapple

Double Dapples are quite simply a dog that has been marked with the merl gene/pattern twice on some of the same areas. For example on a Silver dapple (black and tan) the first time the merl hits the dog it will get grey/silver patches, the second time any where the merl hits the grey/silver areas it will turn white and if it hits black areas previously not hit it will turn grey/silver. Double dapples can be easily indentified by patches of WHITE in addition to normal dapple markings. Double Dapples are not accepted by the KC UK but are by the AKC USA and most European countries where they can also be shown. Quite a few Breeders in the U.S.A specialise in breeding DD's and have produced quite a few outstanding Champion dogs. Double dapples can be bred by mating two dapples - the pups from that mating will be normal colours, single dapple and double dapple. If two double dapples are bred together then all the pups will be double dapples - see the chart below for other combinations. A number of Double Dapples are born with sight and hearing defects and therefore unless a way is found to breed them without health issues this really is one well and truly left to the experts ONLY! Puppy farms/mills/backstreet breeders/ dabbling pet owners all appear to have exceptionally high rates of dogs with sight and hearing issues in some cases as high as 80%.

Work in progress

A lot of what is written here is speculation and as a result is very much work in progress. I have talked to a number of specialist breeders who seem to have had very small number of issues with their dogs. They seem to have built that ability up in their line over a great deal of time therefore I will state here and now dapple to dapple matings are ONLY for those who 100% know what they are doing. Idiots who don't WILL ALMOST CERTAINLY end up getting their hands burned not to mention puppies with various health issues.

Some History on Double Dapples

This excerpt comes from a quite old book "THE POPULAR DACHSHUND by E FITCH DAGLISH 1952" on Dachshunds where a double dapple is referred to as a dapple and white.

The breeding of show dapples has always been regarded as a gamble, but it need not be so. It is as easy to ensure the production of whole litters of dapples of the colour desired for show purposes as it is to breed all red or all black and tan litters. I have already explained that the show dapple, which must not show white markings, represents the intermediate stage between the dapple and white, the dominant form, and the black and tan or chocolate which is recessive to it. That means that to get whole litters of show dapples it is necessary to mate a dapple and white to one of the whole colours. All the progeny will be free from white and will, of course, carry the genes for both dapple and white and the whole colour in their genetic make-up. Years ago, when dapples were more widely owned than at present, double dapple matings were frowned on by breeders on the grounds that they almost invariably gave a proportion of white-marked puppies, which were then regarded as useless either for showing or breeding. All such mismarked whelps were destroyed at birth or given away as pets. To avoid the appearance of these "wasters" the mating of dapples to black and tans or chocolates became the accepted practice. But this mating cannot be relied on to give all dapple whelps. The theoretical expectation is fifty per cent dapple and fifty per cent whole colour, but often fate is unkind and the result is a litter of black and tans with, perhaps, one lone dapple.

I have placed this excerpt to high light the fact that dachshund breeders did breed for double dapples long before puppy farmers / puppy mills even existed to ensure they had complete litters of dapples. They on the whole though killed most dogs with white markings at birth. No reference interestingly is made to dogs being born with health issues only that they had white which seems to have been the cardinal sin. Given so many were killed at birth this may well be why there is no reference. As dapples were around from the first dachshunds so would double dapples also have been around and therefore this great fuss about double dapples does appear to be more about colour prejudice towards white in dachshunds than anything else!

My thanks to Pat Taylor for allowing me to use this wonderful picture of some of her best Show Double Dapples - almost don't look real but they are!

Help we bred one by mistake!

If you have a number of dapples of both sexes with the best will in the world sooner or later that dog will find a way to that bitch. If it happens with non dapples then it's easy to sort out you just dna test the suspect dads against the pups and register accordingly as many many breeders have done and will continue to do so. If it's dapple to dapple many people choose to be very secretive about it all as it's some great crime - why? It's no different to any other accident really. Sadly I have heard many stories of DD's being killed at birth because they will be blind etc - not true; most will be perfectly normal and even blind or deaf dogs can have a really good quality of life! I have also heard of DD's being sold on as a special colour with no reference to the fact the puppy may be blind in one eye deaf in one ear etc - breeder thinks they look ok so that will do. It won't, you need to get a specialist in dogs eyes and hearing to check them out and yes it is expensive! But surely it's worth it. If they do have defects you and the prospective owner need to know that and so you can best cater for that dog through out it's life. We accidently had a litter with DD's in, all of them are alive and well and such lovely friendly little guys. It would have been an absolute crime to have killed them at birth just because we had been told by idiots who have absolutely no idea about DD's that they would all have no eyes or ears! Even if they had been blind and deaf they still have a right to a life! Certainly it may if it was an accident have been much better if it hadn't happened at all but if it does please do the right thing by the dogs and the right thing is to give them the best quality of life possible.

An accidental litter of our own with three Double Dapple pups - Two silver Doubles and one Chocolate Double Dapple

Current Theories on how to breed Double Dapples safely!

Dilute Dapples

There are ideas around using dilute lines that may also substantially reduce the health issues which are mentioned in a number of American Dachshund books but are NOT PROVEN!

WARNING THESE ARE NOT PROVED DO NOT TRY THEM! They are for information and discussion only!

Why bother trying to find ways to breed DD's safely?

People will try to breed DD's no matter what rules and regulations others vainly put in place to contain things so surely if there is a way that reduces these issues it would be much better for them to use it thus reducing the amount of DD's with issues. Essentially I prefer a more proactive approach of understanding the issue and finding a solution instead of a we don't fully understand/so it must be bad so lets ban dapple to dapple matings and that will be the end of it head in the sand approach. Sure it helps a bit BUT it is not by any means the answer as only responsible breeders will pay attention and even they will from time to time have accidents as we have done. PRA can be contained now by testing stock before breeding perhaps something can also be done for double dapples but for that to happen someone needs to get a decent study based on real actual dogs underway!

If you DON'T UNDERSTAND something then you quickly learn to FEAR it! If you FEAR something that rapidly becomes HATE! HATE drives people to DESTROY! To eliminate FEAR you must first UNDERSTAND!

Technical version

Dapple is the name used with Dachshunds but is the same as Merl used in other breeds. Canine coat colour is determined by the expression of a specific combination of genes. A gene, the basic unit of heredity, is comprised of a unique sequence of DNA and directs the production of a specific protein. Proteins are required for the structure, function and regulation of the body’s cells, tissues, and organs. Genes are located within chromosomes. Dogs have two sets of 39 chromosomes in every cell, one set inherited from each parent. The location of each gene within a chromosome is referred to as its locus. While there is more than 99% DNA sequence similarity between dogs, variations in DNA sequence do occur in a small number of genes. Different forms of the same gene are called alleles. Dogs can have two identical or two different alleles for a particular gene. If both alleles are identical, then the dog is said to be homozygous at that gene; if both alleles are different, then the dog is said to be heterozygous at that gene. The genotype of an animal is its genetic identity, as identified by the alleles it carries; while the phenotype, or appearance, is the expression of those alleles. Coat colour in dogs is usually controlled by a set of genes. These include the colour genes, genes that affect the pigment colour of hairs, and the pattern genes, those that affect the distribution of a particular colour. At least 20 genes have been identified that affect coat colour in dogs.

Merle-Dapple Coat Colour Patterning

The merle coat colour is characterized by patches of dilute pigment in combination with areas of full pigmentation. Therefore, the merle gene acts to lighten whatever coat colour would otherwise be expressed. However, unlike other dilution genes, the lightening effect is not spread evenly over the coat, but is expressed as patches of diluted colour scattered over the dog’s body. If the basic colour of the dog is black, the effect of the merle gene is a soft gray, often referred to as “blue”. If the basic colour of the dog is red, the effect of the merle gene is a pale red. The merle coat pattern is characteristic of a number of breeds including the Shetland Sheepdog, Collie, Border Collie, Dachshund, Australian Shepherd, Cardigan Welsh Corgi, and Pomeranian.

Genetic Inheritance of the Merle-Dapple Gene

The merle gene (M) is inherited in an autosomal fashion. In other words, the trait is not linked to gender and can be passed on from either the mother or the father. The gene is incompletely dominant, or a gene that has intermediate expression. A heterozygous dog, carrying only one copy of the merle gene (Mm), expresses the characteristic diluted coat colour pattern. A non-merle dog (mm) is normal in colour, while a homozygous double-merle (MM) is predominantly white. Punnett squares can be used to determine the expected coat colour of offspring when breeding dogs of known genotype (i.e. coat colour genes have been identified). In the example illustrated, a non-merle dog (mm), indicated in the vertical column, bred to a heterozygous merle (Mm), indicated in the horizontal column, will give rise to offspring with an expected frequency of 50% merle (Mm) and 50% non-merle (mm). Dogs that carry the merle gene but do not show the characteristic merle phenotype, are known as cryptic merles. These dogs may give rise to merle offspring. It is suspected that the DNA sequence of the merle allele in the cryptic is shorter than the allele expressed in the typical merle dog. The harlequin coat colour pattern in Great Danes is produced through the interaction of the merle locus and the harlequin (H) gene. In harlequin Danes, the merle background colour is diluted to nearly white with fully pigmented black patches.

Health Problems Associated with the Merle-Dapple Allele

If breed two heterozygous merle (Mm) dogs together it produces the homozygous double merle (MM). Homozygous double merle (MM) dogs may exhibit auditory and ophthalmic abnormalities including mild to severe deafness, increased intraocular pressure, ametropia, microphthalmia and colobomas. The double merle genotype may (can't find any dog data to support this idea) also be associated with abnormalities of skeletal, cardiac and reproductive systems.

1. Ametropia: vision impairment due to a refractive error such that images fail to focus upon the retina.

2. Microphthalmia: a smaller than normal eye due to a defect occurring early in development. Affected dogs may have prominent third eyelids. Other eye defects are common in animals with this condition, including defects of the cornea, anterior chamber, lens and retina.

3. Coloboma: a defect in ocular tissue; a cleft or missing portion of components of the eye, most commonly affecting the iris.

Remember that single dapple dachshunds do not have lethal problems and if a single dapple is bred to a solid (any non-dapple) there are no problems associated with single dapple dachshunds.

Health Problems PLEASE NOTE:

"Around 6%* of double dapples have health problems and it is believed by some to be more of a problem in some lines than in others"  (Note: Puppy farms/mills and backstreet/casual breeders appear to exceed this quite a lot possibly *as much as 80% but I have no evidence to support that directly, just a lot of pictures from American dog/puppy rescue centres with damaged and eyeless dogs)

"Many double dapples are born with no deformities at all" (Note: Blue eyes can look very odd at times with often quite a lot of white which people often mistakenly believe those dogs have issues with eye sight. In my opinion all double dapples should have their eyes tested as a minimum before being sold to be sure)

"Interestingly if a blind or deaf double dapple is bred to a normal dog, the lethal traits are not passed on to the offspring"

Phantom merles

Merles that do not have the merle phenotype (appearance) may still have the merle genotype (Mm). These merles are called phantom merles or cryptic merles. Phantom merles should never be bred because they may produce phantom merle offspring. Phantom merles may accidentally be bred to other merles (Mm) which would produce devastating (MM) merles with the health problems described above.

Other websites with Dapple information

Dachshund Breed Council Dapple information sheet - please click here

Conclusion

It is my personal belief based on the data I have accrued that there is a health issue for Double Dapples and that currently it runs at around 4% these figures are for miniature long haired dachshunds only. There are also very clear indications some lines are significantly better than others In particular double dapple to single dapple seems to have a particularly low rate indeed. Rates for dogs sold by puppy farms/mills is unfortunately not included as currently I have no information from such sources but I believe them to be significantly higher perhaps as high as 70%! Given these places mate mother to son and other unsuitable matings which by default cause health issues it is my belief the DD is simply taking the blame for very bad practises and thus much is blamed on the merl gene when really it lies with idiots! To put DD 6% into context with another issue (PRA) that affects sight in miniature long haired dachshunds, currently the tested rate for Affected PRA dogs  in the UK has a rate of 6%. There is most certainly a health issue no doubt about it although no real research appears to have ever been done on actual dogs of any realistic number and lines and there is a very definite prejudice towards white in dachshunds and this goes back a very long way as out lined in the history section above. It's roots probably lie in the idea a white dog is no good for hunting which given dachshunds are hunting dogs seems reasonable. I would how ever add to that the fact that camouflage for the modern military has over the years become more and more efficient particularly with the use of more and more lighter colours (that were never understood years ago) including in some cases white to break up outlines. As double dapples have been around from the beginning of dachshunds perhaps mother nature knows better than man! Think my figures and or conclusion are/is wrong? Then by all means  please provide me with any significant real actual dog data to prove otherwise and I will gladly change them. For most people my advice is simple don't breed dapple to dapple leave it to those who have been developing their lines over many years specifically for it! If you do by accident then please do the right thing by the dog and let it have a life they have the most delightful endearing temperaments!

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