There are six show-acceptable coat colours for Great Danes
The colour is yellow gold with a black mask. Black should appear on the eye rims and eyebrows, and may appear on the ears.
The colour is fawn and black in a chevron stripe pattern. Often also they are referred to as having a tiger-stripe pattern.
The colour is a pure steel blue. White markings at the chest and toes are not desirable and considered faults.
The colour is a glossy black. White markings at the chest and toes are not desirable and considered faults.
The base colour is pure white with black torn patches irregularly and well distributed over the entire body; a pure white neck is preferred. The black patches should never be large enough to give the appearance of a blanket, nor so small as to give a stippled or dappled effect. Eligible, but less desirable, are a few small grey patches (this grey is consistent with a Merle marking) or a white base with single black hairs showing through, which tend to give a salt and pepper or dirty effect. (Have the same link to deafness and blindness as Merle and white danes.)
(in some countries referred to as Bostons due to the similar colouration and pattern as a Boston terrier): The colour is black and white with a solid black blanket extending over the body; black skull with white muzzle; white blaze is optional; whole white collar preferred; a white chest; white on part or whole of forelegs and hind legs; white tipped black tail. A small white marking in the black blanket is acceptable, as is a break in the white collar.
Other colours occur occasionally but are not acceptable for Conformation showing, and they are not pursued by breeders who intend to breed show dogs. These colours include white, fawnequin,
Merle, harlequin, fawn mantle, and others. Some breeders may attempt to charge more for puppies of these "rare" colours. However, the breeding of white and merle Danes is particularly controversial, as these colours may be associated with genes that produce deafness. Although they cannot be shown, white or merle Danes can usually still be registered as pedigree dogs.
Also it is important to understand that SOME, but not all, Mantles carry the harlequin gene sight unseen. This is now established fact & can be tested for. Those Mantles that carry the harlequin gene can produce a higher percentage of Harlequins than the Mantles that do not have the harlequin gene. No Mantle (no living dog) has two copies of the harlequin gene. So the choices are one or none. This has two consequences:
(1) No dog can breed true for the harlequin gene, and
(2) Mantles & Harlequin-bred Blacks, as individuals, contribute "unevenly" to the production of Harlequins, with some unable to offer any "help" to the increase in the percentage of harlequins in a litter (those without the harlequin gene), while others can statistically increase the percentage of harlequins in a litter from a harlequin x mantle breeding, but actually produce harlequins from a merle x mantle breeding.
A Mantle MUST be bred to a dog that is merle-bearing to produce Harlequin puppies. No Mantle x Mantle breeding can ever achieve this. (This is information directly from the geneticist who discovered both the harlequin & merle gene.)
A Harlequin is considered a merle-bearing dog with a single Harlequin gene: a double heterozygote (MmHh) with black pigment (E-K-). This is a combination of two "dominant white spotting" genes, and produces a white base coat with black torn patches irregularly distributed over the body, head, neck, legs and tail. Without recessive white spotting genes (Irish" or "piebald"), the Harlequin will usually be referred to as "heavily marked." When the Harlequin has extensive white from the action of the more recessive of the "S locus" alleles, then it will be referred to as "lightly marked." When carrying only "Irish" alleles, the Harlequin will be thought close to the ideal under the current breed standard. Harlequins are unique: like snowflakes no two are ever just alike. And their markings can be very pleasing or not-so-much when the dogs are identical as to genotype (and so to breed ability). This isn't a colour that will "breed true" in any sense of the word and simply cannot be standardized beyond some basic range of markings. A wide range of markings (from heavily marked to lightly marked) is allowed under the breed standard & variations within the standard shouldn't be heavily penalized. And note also that ALL Harlequins have some merle markings.
The heavier the markings on the Harlequin, the more merle is visible to the casual glance, just because the dog has more pigment in general, but all true Harlequins that are not altered in appearance have merle markings somewhere because Harlequins _are_ a form of merle (this is a fact documented at the gene level and has always been understood by the experience Harlequin breeder). And merle markings are not the gun-metal gray colour of our blue Danes (which is a totally separate gene): merle is not always some pale shade of silver or even an obvious gray; merle is referred to as a "mouse" colour, that is gray-brown, and these merle patches can appear "tarnished," so the merling can be more tan to chocolate in appearance. This does not mean the Harlequin is "showing" fawn or chocolate pigment (a genetic impossibility) and does not mean the animal in question is even carrying for these other recessive pigments. Merling may not be necessarily aesthetically pleasing, but it's a natural part of the Harlequin pattern. So it shouldn't be weighted heavily against the dog, in that it's purely aesthetics, a completely random event, and has no real bearing on the dog's breed ability as doesn't reflect some change in the basic genotype for Harlequin. It is also worth noting the lighter the dog is, for all that means the less likely merling is obvious, the more likely that hearing and sight will be adversely affected in potential offspring. So it just doesn't make sense to penalize dogs more heavily for having heavier markings when the dog still fits the standard, particularly since it is pigment that protects the Harlequin from the health problems associated with merle. (Never mind the standard is explicit that faults should be penalized by the amount of deviation, not the direction of deviation.) Most everything in breeding Harlequins involves trade-offs; this is just one example. That these simple facts about merling are not widely appreciated is a constant frustration to the experienced Harlequin breeder, who is already labouring under quite a burden to produce show marked dogs.
Part of the take home message here should be that *COLOUR* has been far too much the focus in both judging and breeding, while there has been too little emphasis on **PATTERN**: Pattern is the stable point in Harlequin breeding, the one place where all good quality breeding stock and correctly marked show dogs have both looks and genetics in common. This simple fact has been very much undervalued and overlooked it would seem. Pattern genes are a critical component in getting correct colour and arguably the most critical component as pattern, indubitably, is the most certain point of control in producing correctly marked Harlequins & Mantles. Colour (Harlequin, Merle, Mantle, White) just describes how the various necessary genes to produce Harlequins statistically sort in the population/gene pool & there isn't control over this in any real sense (i.e. you cannot find a breeding to rid the gene pool of all but show colour). Pattern on the other hand can be managed and maintained: there is one true breeding (the Irish homozygote) show mark and a couple of hybrids (the pseudo-Irish dog that is anIrish/piebald heterozygote) that can produce show markings. So the **PATTERN**that results in the show-marked Harlequin & Mantle (and Merle when/if that's accepted) IS THE SAME PATTERN: all show-marked Danes in the Harlequin family have to have, need to have, the IRISH PATTERN to meet the current standard. Therefore it's pattern, not colour, that should be the focus in Harlequin breeding. Control the pattern & you create a situation where you can maximize the number of show marks. Consider everything equally breed able as to colour/pattern & you lose control.