The title of this column is somewhat misleading, because for some genetic problems in some breeds the future is NOW. The health clearances of the future will be DNA clearances – actually checking for the genes which cause the problems or defects.

Currently a couple of different type DNA tests are offered for different problems. (Please note that this is different from the DNA profiling which registries like the AKC and the UKC are doing. The profiling is simply an identification test for a dog. It says nothing about health or individual genes, at least at this time.) The tests are checking for either the mutated gene itself, in which case the test results are black or white, or for a genetic linkage, which leaves us a few areas of grey. In linkage tests, a marker gene has been identified which often "travels with" the defective gene. With ideal linkages, the defective gene travels with this identified link almost 100% of the time.

Let’s use PRA testing as an example here. Irish Setters have had the defective gene which causes PRA (Progressive Retinal Atrophy) in that breed identified, so a blood test or cheek swab can be sent in and the result from the labs who do this is one of three: Clear, Carrier or Affected.

Now, you simply remove the affecteds from the breeding populations altogether if possible. You only breed Clear to Clear with all normal pups as a result, or you can breed Carrier to Clear and test all pups to be sure which is clear and who is a carrier. In some breeds, the number of affected dogs may be so high that you need to use affected dogs in the breeding program. With this type of test, you can breed an affected dog to a clear dog. With simple genetic situations, all the pups will be carriers, but they can then be carefully bred to clear dogs.

The situation is a bit murkier with the linkage/marker tests or in tests with some false alleles. The tests for the PRCD form (Progressive Rod Cone Degeneration) of PRA in Labrador Retrievers and some other breeds is an example of a linkage test using markers so close to the diseased gene that no recombination between the markers and gene have been detected. There is still the issue of the "false allele," however. This test will give you three results also, but they are not so clear-cut. The dogs rated Clear or A are normal themselves and will not produce affected dogs if bred to other normals, to carriers or even to affecteds. The dogs rated B or Carrier are not ever going to be affected, are probably carriers – some of them may even be clear in reality. The dogs rated C or Affected are very likely to be affected themselves and at the very least carriers.

Breeding plans get a bit trickier here. Certainly breeding A dogs to A bitches should give you all puppies normal for that problem. A to B should give you puppies that are themselves normal but could be carriers. A to C should again give you normal puppies which are very likely to be carriers, and breeding B to C could give you a variety of results! The nice thing about DNA testing is that even with risky breeding, very young puppies can be checked and their status identified before they go to new homes.

Currently two companies are set up for genetic testing in dogs. One is OptiGen, which at this time has DNA tests via blood samples for a number of eye disorders. These tests are based on research at Cornell University and are licensed from Cornell. Breeds covered at this time are Irish Setters, Briards, Chesapeake Bay Retrievers, English Cocker Spaniels and Portuguese Water Dogs. Poodles should be added soon. This group is setting up breed databases and DNA archives (storing DNA samples for future use), and it offers genetic counseling. OptiGen is located near Cornell University in upstate New York.

VetGen is the other current DNA testing company for dogs. This company uses cheek swabs and was developed via a cooperative project between Michigan State University and University of Michigan. Start-up funding for the research came from the AKC, the OFA and the Morris Animal Foundation, all of which now reap some of the benefits. VetGen has a number of tests available, ranging from PRA testing in Irish Setters to renal dysplasia marker testing in Shih Tzus and Lhasa Apsos. Coat color predictions can be performed for some sporting breeds and von Willebrand’s testing is available for a number of breeds. This company is currently working on hip dysplasia and epilepsy as well (these are very complicated inheritance problems and it may be difficult to come up with a definitive test). VetGen also offers DNA archives.

None of the tests from either company are "cheap," but compared to the alternatives they are almost miraculous. I remember a friend having to do test breedings to be sure her Irish Setter was PRA clear, and what a heartbreaking and expensive situation that was! Discounts can sometimes be arranged for litter testing and both groups have ongoing projects and may request samples for research.

DNA testing certainly is the wave of the future and will make breeding decisions much simpler from a health standpoint.