Breeding an EIC Carrier to an EIC Carrier can produce Clear (25%). You take two Clears that were each produced by both parents being Carriers, and breed them together. Could that mating produce a Carrier?
Breeding an EIC Carrier to an EIC Carrier can produce Clear (25%). You take two Clears that were each produced by both parents being Carriers, and breed them together. Could that mating produce a Carrier?
Two clears can only produce a clear, no matter how the parents became clear.
I'm just not sure that it is as easy as that, what with affected dogs not collapsing. I can't help thinking there is more to it that a simple recessive.
Affecteds not collapsing is an matter of incomplete penetrance of the mutation. That has no bearing on breeding two clears together. If you only produce the clear genotype, it doesn't matter what the expression of the mutant type is.
From optigen
Penetrance - The extreme case of reduced expressivity is incomplete penetrance. An inherited disease has incomplete penetrance in cases where the individual is known to have the affected genotype, but never shows the clinical disease. Even so, the clinical disease shows up again in its offspring. Clearly, the affected genes were present in the parent but the disease didn’t “penetrate” to a recognizable state. Again, this case must not be confused with a case of false positive. Incomplete penetrance has been documented in some PRA-affected Toller pedigrees.
Originally Posted by anon
Affecteds not collapsing is an matter of incomplete penetrance of the mutation.
Has incomplete penetrance been documented in non-collapsing EIC Affecteds?
What is the result of breeding non-collapsing Affected to non-collapsing Affecteds?
What is the result of breeding non-collapsing Affected to non-collapsing Affecteds?
Non-collapsing affected dogs can produce collapsing affected offspring. That information is published on the University of Minnesota website in the fact sheet about EIC.
I have a friend who, before the test became available, bred a carrier to a MH non-collapsing affected (E/E). This dog had ample opportunity to exhibit the phenotype. Multiple puppies in the litter collapsed and cannot be used for hunting or field training. Ironically, my friend went to this particular stud dog because she thought he would be safe, as he was not related to any of the carriers of which she was aware. The fact that an individual dog did not collapse does not ensure that the offspring will not collapse. Some people claim to have lines that should have produced collapsing dogs and have not. Possibly those lines have a protective genotype that doesn't allow the expression of the E/E genotype. But an outcross could still cause the collapsing phenotype to appear. Since the test became available several years ago, I have been contacted by several breeders who did not think EIC was serious and became believers the hard way.
The respondents are correct that a clear/clear breeding will produce only clears. Even if all four grandparents are carriers, if none of them passed the gene on to the parents, the progeny will not have the gene.
