Genetics 2

Genetics II

Designer Dogs and More

Here’s a quick quiz about designer dogs. If you are not sure what a designer dog is, it is a cross bred between two breeds. In other words we are talking about labradoodles, puggles, and yorkipoos to name a few. Please decide which statements are true or false:

They are cute and fun to look at and fun to own.
Poodles are often used as one of the parent breeds.
They are healthier because they are crossbred.

Number one and number two are true. In fact, number three is false. Taking a closer look at number three is warranted because it seems like it ought to be true.

Let us go back into the mists of canine prehistory. During the ancestral development of dogs they had a very large common gene pool. In that gene pool there were, of course, several defective genes floating around. This is true of any population.

Then people started breeding dogs for various purposes. Due to a phenomenon known as gene slippage a large variety of dog types were created. As these types were created many breeds carried the ancestral defective genes with them. So there are large numbers of breeds that carry the same genetic problem.

For example there is a genetic eye disease called progressive retinal atrophy (PRA). The genes that cause this disease are found in at least 22 breeds. These breeds include the labrador retriever, the golden retriever, the poodle, and the cocker spaniel. So if you cross these breeds you are just as likely to have PRA than if you have a purebred of any of the affected breeds.

There are many common hereditary diseases that occur across purebred, designer bred and cross bred dogs.

So what is a designer lover or any dog lover to do? Genetic testing of all purposefully bred animals is the only ethical answer. There are several genetic registries established to assist breeders and owners with genetic disease control. Ask either Dr. Sheffield or Dr. Ferguson about these registries. They will be happy to assist you with this important component of animal health.