ZUCHTVERBOT FUER GEFLECKTE DEUTSCHE DOGGEN

"Harlequin Breeding Forbidden in Germany"

An ancillary article to the recent animal-rights driven attempts to restrict breeding and the recent DDC policy of forbidding the breeding of Harlequins appeared in Der Hund in September 1995 authored by well-known breeder and scientist Herr Dr. Friedmar Karutwurst (author of Die Deutsche Dogge: Herkunft, Zuncht, Haltung). That article was translated and printed in the Great Dane Reporter Sept/Oct 1996 with permission of the author. An improved translation is offered below. Translator (on both) JP Yousha. All rights reserved.

Note please that a ban on Harlequin to Harlequin breeding effectively limits the breeding of Harlequins to Black/Mantle only. Merles and other mismarks are not traditionally used in European breeding programs (which is why they are not even discussed in this article). And the purpose of this ban is to avoid entirely the production of potentially defective MM ("white") Danes, which would also be produced by using merles as well as Harlequins of course. So the below should not be interpret as to advocate the breeding of merles and other mismarks; quite the contrary. Harlequins bred to Black/Mantle is the Great Dane equivalent of merle to bi/tri-color dogs in collie breeds: it avoids making MM puppies while using dogs recognised under the breed standard. This is a typical strategy in breeds where the merle gene exists.

I will begin by anticipating my argument: there is no well established genetic knowledge concerning dog breeding to serve as a foundation to the recently enacted breeding ban. This is not to suggest that the animal activists behind the recent ban are insincere in their intentions, for it is undisputed that the gene that produces Harlequins and merles, when present in a double dose, can result in defects of the sensory organs. However one must certainly condemn the hasty classification of Harlequin breeding as intrinsically injurious or "abusive" (Qualzucht) as no specific evidence has been offered for that claim.

It must be noted than these so-called "reports of sufffering and damage" (upon which the ban was based) do not refer to any scientific literature where there has been a direct examination of the Great Dane. In fact, the examination of merle animals was confined to a small number of dappled Dachshunds. From such a limited base is indeed be very risky to make claims that result in defining the legislation of dog breeding in general. First one would have to be able to determine if an extrapolation from the Dachshund population to other breeds is even justified. Do we even know if the genetic inheritance from breed to breed of similar phenoptypic characteristics is even identical, completely seperate, or even results from completely opposite effects?

Knowledge concering the mode of actions of the merle factor when present in a single dose, as exists in the Harlequin Great Dane, remains unanswered in the current literature, as do questions concering its penetrance and expression. For the representatives of these political and animal rights groups it may suffice that any breeding of dogs of these coat colors can be labeled as "abusive." However their actions unfortunately are likely to have the opposive of their intended effect; instead of the preservation of a breed with more than a hundred year of cultural and historical significance, the destruction of this valuable type of dog is likely to be the result.

The merle factor is considered to be a dominant genetic mutation which inhibits, partially or completely, the pigmentation of the coat. The partial inhibition of pigment appears phenotypically as a Harlequin or merle, or other patched or spotted coat types, depending on the base coat color and what other recessive genes are present. If one begins by designating the homozygous black Great Dane as mm, then designates the Harlequin as an Mm genotype, the presence of the dominant M allele results in the partial reduction of pigment. With the complete mutation of both alleles to the merle factor, a genotype of MM exists, with a near total loss of pigment and a white Dane resulting. Therefore, one can deduce that in Harlequin breeding there are three different gene pairs producing three different phenotypes:

mm - Blacks = do not carry the merle factor

Mm - Harlequins = single-factored for merle, i.e. heterozygous for merle

MM - Whites = double-factored for merle, i.e. homozygous for merle

Clear and specific knowledge about the merle factor and its relationship to structural defects has particular significance for the breeder. These defects typically appear in the form of sensory organ anomalies, such as variable congenital eye and ear defects, as well as reproductive disorders. Because such defects can be problematic, and in that they may not be apparent immediately, the cause and connections of the desirable and undesirable features that result from the merle factor and the mode of operation in both homozygotes and heterozygotes needs to be established. The linkage through which the merle factor mutation produces both loss of pigment and defects of the sensory system can be accounted for by the connection between the shared source of melanocytes, skin, and nervous system structures during early embryonic (i.e. neural crest) development. The resulting pleitrophic effects of merle seen in individual animals, of reduced pigmentation and sensory anomalies, can be postulated as arising from this early association in the neural crest. Simply stated, these defects can be attributed to the development pathway of these early neural structures in close association with the initial stages of pigment development, which later develop into the sense organs.

In contrast to the data gathered on the white (i.e. MM) Great Dane, which carries the merle factor in a double dose, the association of sensory defects with the Harlequin (i.e. Mm) Great Dane, which carries the merle factor only in a single dose, cannot be established. Thereby the classification of such breedings as intrinsically "abusive" cannot be established. The German Great Dane Club (DDC) has determined that, as a prerequisite for breeding Harlequins, a hearing test with normal results must be furnished. A similar requirement for a vision test is currently being established. Such testing on a wide scale will provide increased information regarding the genetics of breeding Harlequin Great Danes. It may be possible in the future to ascertain whether there is an association beween the location and size of pigmented areas and sensory function, and whether this is a general phenomenon or varies from individual to individual.

The prohibition of breeding Harlequin Great Danes to each other recently enacted by the German Great Dane Club is rather sweeping, but will avoid entirely the production of white (MM) Great Danes. Our breeders should certainly be aware that, statistically and according to Mendelian laws of inheritance, the mating of two Harlequins will produce <sic> 50% Harlequins, 25% white, and 25% black Danes. From an analysis I have done over eleven years and including 2200 progeny of Harlequin to Harlequin matings, 14.6% of pups born were actually MM white Danes. These results do confirm the assumption that the merle factor in a double dosage is sublethal: a high mortality rate between conception and birth (i.e. embryonic death and fetal reabsorbtion) apparently results for MM dogs. The currently imposed restriction of mating Harlequins only to black Great Danes will result, on average, in 50% Harlequin and 50% black progeny. Double-factored white MM Danes cannot result from such matings. And the wise selection of breeding stock from these breedings can also produce well marked Danes. Blacks from these breedings are free of the merle factor.

This discussion would not be complete without a comment on the widespread confusion concerning the description and phenotype of so-called white Great Danes and their associated sensory defects. In the venacular and the literature, MM Great Danes are generally referred to as "White Danes." However this term is lacking in descriptive power in the same way a "Harlequin" is as a term for the spotted or patched Great Dane. In the German breed standard the "White Dane" is defined as a "Dane without any black markings (albino)." Both portions of the definition are faulty. A completely white double-factored (MM) Great Dane is rarely found, and albinos do not exist in the breed. In distinction to the description of merle factored dogs, albinos are produced only when both alleles at the C locus are recessive. In these cases the chemical reaction that produces tyrosine, a precursor to melanin, is interrupted. Therefore any trace of pigment will fail to appear in the albino.

The genetic definition of the MM double merle-factored Great Dane and it's associated phenotype is very complex and is poorly understood. I know of animals recorded as White Danes that have no sensory defects of any kind. White Danes, particularly those that result from matings between Mantles or piebalds and Harlequins, can only carry the merle factor in a single dose if at all. If they do not inherit the merle factor their white markings will be determined by other, seperate, recessive genes. Further discussion of the variety of possibilities for producing White Danes is not within the scope of this article. However if the breeder observes the new provision of the German Great Dane Club (DDC), there can be no more reason for classifying the breeding of Harlequin Great Danes as "abusive."