Genetics
Some thoughts on genetic disorders and breeding:
Please talk to vets and people who know about this. What I know, is a small piece of what they know. Also read the Poodle Club of America web site on diseases of poodles so that you can be a knowledgeable buyer.
http://www.poodleclubofamerica.org/purchasepamphlet.html
This primer on dog genetics may help too. Note - this is the full address but you have to get to the page by going to the first part and clicking the dog genome button, then the one for dog owners etc.
http://research.nhgri.nih.gov/dog_genome/info_for_dog_owners/primer.shtml
Genetic testing: The PRA story.
Anyone who was involved with poodles during the spread of PRA knows that it is critical that breeders do full genetic checking on the sires and dams before breeding. Friends have told me of the heartbreak of having a dog go blind at the age of 6. My dogs are all clear of the PRCD form of PRA, but there is a second rare form that can’t be tested for with the genetic tests yet. So in addition to the PRCD test, CERF is necessary. You should understand this genetic disorder before you buy a puppy. This link will take you to the company that does PRA testing: http://www.optigen.com
Hundreds of breeders stopped using their beautiful breeding champions that were not tested clear. Many did this even in the early days, when the test was still not completely reliable. I would ask that you honor their persistence, ethics, and effort and ask your breeder for the papers on PRA status. Poodle breeders have spent millions of dollars to provide puppies that are free of this disorder.
Lilleba provides a list of poodles that tested A or clear of the disorder. http://www.poodleinfo.no/prcdPRA.html There you will also find a list of dogs bred by hundreds of owners and breeders who have helped to reduce the impact of this disorder. There are over 1,000 that are listed as clear. Note, in order to look up a dog, you have to know the spelling of the registered name of the dog, not just the call name.
Optigen now reports that ‘Statistics to date are very similar for Toys and Miniatures, showing 68% are “Normal/Clear,” 28% are “Carrier” and 4% are “Affected.”‘ This means if you buy from a breeder who does not test, there is a 4% chance that the puppy you love will get PRA, and 28% chance that the puppy will carry the PRA gene and be able to pass it on.
Genetics in general:
In human beings there are over 8,000 problems that we can test for. What this means is that all of us, humans, are probably carriers for some rare genetic disorder. The same is probably true of dogs. Unfortunately in dogs there are only a few genetic tests we can do.
Genetic disorders cause early mortality in people, dogs, and probably in all animals.
The mortality rates are very high during pregnancy if there is a whole chromosome disorder. For example only 25% of trisomy conceptions proceed to term. That is why so few people (or dogs) are born with multiple or missing chromosome disorders.
Disorders from missense or nonsense coding for even a single gene can cause mortality when the activity of that gene reaches a critical state. Some of these are recessive genes and are only expressed if there are 2 genes present. In people, these disorders cause early deaths that everyone recognizes such as CF, Tay Sachs, or MCADD, which may be responsible for some SIDs deaths.
Multiple gene disorders tend to cause mortality later in life but before old age, such as a rapidly aging heart or my father’s cancer.
Dogs have many of the same disorders we do. http://research.nhgri.nih.gov/dog_genome/
Understanding the dog’s genetic structure is helping to understand disorders in human beings.
UC Davis is doing research on Addison’s and Epilepsy. They need samples from both dogs that are unaffected and dogs that are affected. If you have a poodle you can help by sending samples. Go to http://cgap.ucdavis.edu/Default.htm
We can eliminate known health problems once there is a genetic test. However, achieving a beautiful healthy puppy is hard work. How do you select for good characteristics and get rid of bad ones? The adult is formed from both genetic and environmental factors. We know this from experiments involving mass breeding. For instance, only 10% of the baby trees grown from seeds generated from 2 adult trees that grew very rapidly, will also grow very rapidly. If a dog came from 2 healthy adults and the dog develops a disorder, some of the disorder may be genetic and some of it may be environmental. Be good to your breeder and tell them about the health of your dog. Just a little call saying the dog is healthy or has developed a disorder will help. You can’t tell anything from one dog. But if the breeder knows there is a problem for more than one dog, then they can review the situation to see if there is a genetic component.
In nature, the gray wolf pack, from which all dogs descend, uses line breeding in the wild. http://www.idir.net/~wolf2dog/wayne2.htm Generally families stay together and often cousins breed. However, wolves also roam and join other packs if something happens to their family. What this means is that the tiny differences that make for survival in a specific environment can be accentuated and bred into the pack in a few generations. Genetic disorders probably surface too. The difference here is that nature kills all the wolves who do not perform optimally. The beauty of the pups and their perfect fit for their environment is a function of this cruel outcome. This is not an option for us.
So breeders cull by deciding a puppy should not be allowed to breed. These puppies become pets. A pet poodle may have some small thing wrong. In poodles it is often something fairly trivial that makes it not conform to the breed standard. For example, in my last litter one puppy was very pretty but grew too tall and can’t be shown. My son’s dog, Ninja, was born with an under bite. He grew out of it and his bite was fine by the time he was one year old and he lived a happy life with us for 12 years. Other times it is more serious. A friend of mine just had a litter and one puppy was born with a hernia. He had surgery and is happy and ready to play. But given the nature of his disorder he and all his siblings will go to a pet home. The breeder does the culling that nature might do.
But there are things we can’t see, or that don’t develop until later in life. So what can breeders and puppy buyers do? I have my dogs checked for testable genetic disorders found in miniature poodles. I can give you copies of the tests. Then I guarantee the puppy. You should look at any breeder’s tests and the contract to see what they guarantee.
I advertise at this web site. When I signed up I had to prove that I have done genetic and other testing I was claiming for my dogs. You can ask these poodle breeders for copies of their test results. www.poodlesonline.com