PHENOTYPE IS NOT GENOTYPE:

PHENOTYPE IS NOT GENOTYPE:

or Why The Irish Gene Is Not The Mantle Gene

The whole point to understanding Mantledane genetics is that we 'straddle' TWO genes (si and sp) by asking for a whole and complete collar as the ideal pattern, while penalizing the other iterations of both piebald and irish patterning. Both genes (alleles) could be in the breed and if one is missing it is the irish NOT the piebald.

If we had allowed the Mantledane, like the Collie or Boxer, to have white up to and including 1/3 (but no more), we would have been selecting for the irish allele. Had we asked for at least 30% white and allowed up to nearly all white, we would have selected for the piebald allele. As it is, we wrote the standard is written to select for a PHENOTYPE, not a genotype, so we end up with a large variety of genotypes that fit that one phenotype. Which means that all those pretty marked Mantles may have very different genes, meaning dogs who look alike won't throw alike, so predicting pups from the parents (as to color) has some problems. Here are some examples of genotypes that could create the ideal mantledane pattern and its allowable range by the illustrated standard:

1) Ssp and Sse--both are the so-called "pseudo-irish" that are created by a breed, like Cocker Spaniels that allows for solids and piebalds. This is thought by many to be what creates a flashy Boxer (not the irish gene) and obviously represents two genes the Great Dane DOES carry (as solids-fawn, blue, brindle, black, must be SS and harl families commonly exhibit the spsp pattern.) These dogs, when bred to each other, often have solids and very white dogs as well as more irish patterned offspring. The range of pattern shows it is a hybrid. No more than these two genes need be in Danes to explain everything from solid fawns to boston-headed dogs, and all possible white and solid pattern combinations in between. So see how Mantles, piebalds and solid Danes can be related, click here.

2) sisi--"true"(homozygous) irish--most irish dogs, however DO NOT have a collar, only throat and belly white, that is they are NOT mantles, but mismarked blacks (when you are talking about the Dane). Look at the Collie as an example. Irish is NOT the "collar" gene, it codes for "white trim, but less that 1/3 white total." Many mismark blacks are "pure" irish. Breeds who 'depend' on the irish gene, like Bernese Mountanin Dogs NEVER demand a full collar, but they do penalizes excessive white. It is only speculation that breeds like the Basenji carry exclusively for irish (to make a collar) and that speculation is based merely on the idea of the pattern in such breeds being so consistently symmetrical, which is not normally thought to be a characteristic of the piebald gene. It would be just as reasonable to claim that modifiers made the piebald gene stabilize to symmetry of pattern, as to claim that somehow the irish gene has altered its normal range to consistently produce a 1/3 white dog.

3) spsp-the piebald Mantle--also "pure" or homozygous--this is the flashy boston who typically "drinks his blaze" (with a split head blaze and full and complete collar from the backs of his ears to his shoulder blades). These dogs will likely have breaks in the blanket (as may, BTW, dogs with only one piebald gene!). Dogs with extensive, flashy white markings, where the black on the head is only around the eyes and ears, with full white collars, and dogs with breaks in their black blanket carry the piebald gene, as the irish gene cannot extend it's production of white this far from what we understand. A piebald (sp or maybe se also called sw) gene is also then likely present when you have asymmetrically marked dogs, such as split headed dog-with one side of the head black and the other white, as well as those dogs with white socks on one side and high white stockings on the other. This is the gene that Brittanys, for example, carry. The markings are less symmetrical than with the Irish gene.

4) sise/sisp--the hybrid Mantle--this, like the "pseudo-irish" give the appearance of a mantle, but the genes here, again, are different, so the dog does not consistently breed the pattern it carries. These animals produce many very white (lightly marked) harls and dogs lacking body color. Such dogs CAN produce mantle-headed or even nearly completely white dogs who do NOT carry the merle gene. It is even possible that sese Dane pups could be deaf whites with blue eyes. These animals would NOT be (white-double-MM) merles or harls; they would have the same basic genetics as the Dalmation or Bull Terrier and have the same reason for going deaf.

The take home message is two-fold: #1. there are several possibilities for genotypes that will appear as a 'perfect boston,' but they will breed very differently, as the one phenotype can be made by a variety of gene combinations and #2. breeding flashy animals (harls or mantles) will increase your chances of getting deaf pups. Again, to avoid problems (and a lot of study!), simply use the illustrated standard as your guide and avoid the use of mismarks if proper pattern is your goal. The article published in the Great Dane Reporter (stud issue 1997) not only gives the details of Mantledane Genetics (its title), but also illustrated the range each type of mantledane can produce from its "hidden" genotype.

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