Interlude: the DNA test

As many of you know, there is a new test for the inheritance of DM (Degenerative myelopathy.) You can find information on it here: DNA Test

Initially, on hearing the gene had been found, I was delighted, and thought, no one will ever need to breed a dog with that gene again!

Well, as details emerged, it became apparent that in Pems, at least, this was not to be the case. First, although it appears to take two copies of the gene to cause DM, the gene is firmly entrenched in the breed, with up to 50% having the dreaded two copies and another 40% being carriers. (These stats will probably improve as more dogs are tested but won't be anything but dismal.) So not breeding any dogs that have the gene (an SOD1 mutation) is not going to work. There are, to date, precious few clears (no mutated genes) for anyone to breed to, so even breeding dogs to clears is not always a possibility.

A further complication is that not every dog with both copies of the mutated gene (At Risk dogs) get DM. The percentage that do is still unknown but my guess is between 20 and 50%, with the percent increasing with the age of the dog. I hope it is lower, I fear it might be even higher. Nobody knows, but luckily we should know soon, as researchers are testing a large number of dogs over age 10 and following the At Risks to see if they develop the disease.

So it turns out that the best breedings (Carrier or Clear or At Risk to Clear) are hard to come by, and some breeders will have to breed Carrier to Carrier to get Clears for future breeding. Some are adamant that they will not do this and produce a possible DM dog, but I think, being realistic, its going to take one more generation to get enough clears.

So that's the situation, and you'd think Pem breeders would be jumping on board with testing and doing selective breeding. And a few are, but sadly, these are mostly the ones who themselves have nursed a DM dog to the end and know just what kind of heartache this disease produces. Not everyone- I know at least one breeder who has never had the disease in her line but still is breeding to eliminate it, and kudos to her and to everyone else who cares enough to select against the SOD1 mutation.

If you are a puppy buyer, be aware that YOU can ask for the test. It takes only about two weeks to get a $65 cheek swab test done. Put your deposit down contingent on the pup being clear or carrier (neither of these can get DM.)