DM testing....how young? - Page 2

My question is actually for anyone who thinks it's a good idea to test puppies. If you end up with At Risk puppies, who will buy them? If you can't sell them, what happens? I have been told there is only a 20% chance of these dogs ever developing DM, but the newly educated public IMO will not be willing to take the chance.

Normal x normal = 100% normal
Normal x carrier = 50% normal, 50% carrier
Normal x at risk = 100% carrier
Carrier x carrier = 25% normal, 50% carrier, 25% at risk
Carrier x at risk = 50% carrier, 50% at risk
At risk x at risk = 100% at risk

These are only approximations based on many more puppies than we would normally see in one litter, so the percentages in any individual litter may deviate from the norm. Carrier x normal could produce all carriers or all normals. It's like tossing a coin 100 times; in the end one would expect 50 heads, 50 tails, but the first 5, 10, even 15 tosses could have been all heads (or all tails). The one fact you can count on - at risk x at risk will always produce 100% at risk and normal x normal 100% normals. 

What to do with the dogs that test at risk? If they are breed worthy, they can still be bred with the expected results above. Using only normals will eliminate the gene in 3 generations and will not produce anymore at risks. Each puppy will need to be DNA tested and only the normals retained for breeding. This is probably not a big deal for most GSD breeders since most puppies go to pet homes anyway and it won't matter to a buyer who doesn't want to breed the dog if it is a carrier or a clear. I assume most sell their pets with non-breeding contracts and/or limited registration.

 

 

 

gagsd4, that's a great question and another compelling reason to test before breeding so no more at risks are produced. If it happen to me I think I would arm myself with as much information about DM as I could, share that with potential buyers and let them decide.

First, It's important to note that this test is of great importance if used as a breeding tool, and should be considered no differently than any other important piece of imformation which good breeders take into consideration as they make choices for their prospective pairings. 
Dogs who test as carrier/clear will not get the disease. 
Dogs who are carrier/carrier may also not show symptoms of the disease, and may die from something totally unrelated without ever showing signs of the disease. 
Dogs who have been afflicted with the disease have been confirmed that their DNA has two carrier/carrier DM genes.
At risk dogs for getting the disease (carrier/carrier) can also produce offspring who are CARRIERS ONLY (carrier/clear), when mated to dogs who are Clear/Clear.  These offspring will not get the disease nor show any symptoms of the disease.

The true benefit of this test is to know what you are breeding FROM, and what you are breeding TO.
Even excellent breed worthy representations of the breed who may test as carrier/carrier should not AUTOMATICALLY be eleminated from the gene breeding pool...but they SHOULD only be mated to Clear Clear mates.  It would then be possible to eventually continue future breedings from this lineage with the prospect of breeding this mutated DM gene OUT.   If you don't test at all, you can see how easy it would be to be breeding pairs who are carrier/carrier, without ever knowing since they may not be manifesting any symptoms of the disease during their early breeding years. 

  

Pups only inherit the genes responsible for DM directly from their parents...Each dog has only 2 DNA DM genes, which are inhereted from their parents, one gene from each.   Their ancestors are not part of each dog's personal equation, except for so far as what they each contributed to these particular pair of parent dogs.  Therefore if you breed ONLY parents who are both clear/clear, ALL resulting offspring will ONLY be Clear/Clear. 
If you have an at risk dog (Carrier/Carrier),  even this dog if bred to a Clear /Clear will only, at the worst case scenario, produce Carrier /Clear puppies, (which the whole litter will be) and who will not be at risk for getting the disease. 
Pups from these litters will be, at worst, ONLY carriers (carrier/clear).  
Litters which result from a carrier/carrier parent with a clear/clear parent would ALL be carrier/clear pups 100%, and even these pups, when bred in the future only with clear/clear mates can go on to produce clear offspring in the future, although testing would be required within each litter to determine who is clear/ clear and who is clear/ carrier.  Breeders can choose to keep back only their clear/clear pups, and continue on with this lineage using only the clear clear offspring.  By testing litters of carrier pups and keeping back for your breeding programs ONLY those pups who test clear/clear, you will then eventually only produce clear offspring and nothing else.

 

what is DM

thank you

http://www.schraderhausk9.com/Degenerative%20Myelopathy%20Testing.htm


http://www.caninegeneticdiseases.net/DM/basicDM.htm


http://www.caninegeneticdiseases.net/DM/resrchDM.htm 
 

   

I believe there is one gene responsible for DM. Genes are inherited in pairs, one half of each pair coming from each parent.

If only the DNA test in GSDs correctly identified all types of of DM in the breed.... 

It's still worthwhile to test for, but it's only snagging part of the problem--at least at this point.

Oh, ok gagsd4.  It's slightly new to me so I'll be testing him and his parents as well.   I do know it isn't common in the Huskies, and I've seen maybe one or two breeders who do that on their Huskies.....So why not start doing it as well.