Saturday, February 16, 2008

Genetic Disease or Poor Health?

(This blog originally posted on 3/23/2006.)

Thorough genetic screening enables responsible breeders to minimize their chances of producing a health-compromised puppy.

This seemingly benign sentence is shaping a dangerous trend in dogdom. Maybe more than one. This statement has become one of the mantra's of "responsible" breeders, and surely nobody could argue with it!

Nobody except maybe Ms. X, who never hesitates to pick up the dog poop and throw it in the composter, rather than just side-step around it. And maybe her furry readers, who are becoming experts at clearing the poop mines out of the yard in record time.

Let's start at the top. "Thorough genetic screening..."

Even with rampant inbreeding there are relatively few diseases in dogs proven to be monogenic. You know from the posts and readings on epigenetics that most diseases have environmental factors. And genetic screening means screening only those diseases that have some degree of identifiable genetic component.

So right away you know allergies, asthma, cancers, etc. have been excluded from this screening requirement.

What genetic screening does do, is shrink the genepools. When they write "enable breeders to minimize ... producing" they mean by not breeding animals that do not pass genetic screening.

You minimize producing by minimizing matings.

Some will take an extreme position here, and stop breeding every dog linked to a genetically related disorder, while others will limit the breeding of those dogs to only "clear" ones. At the end of the day though, the results are the same. The genepool shrinks. It's just a matter of time.

Things happen when the genepool shrinks. For one, when a particular disease is "selected against" or a physical trait is selected for, it's not uncommon for a new, previously rare, or unheard-of disease to suddenly become prevelant and widespread. Usually this is referred to as doubling up on bad genes.

Something else happens too, and it's much worse. Good genes are also doubled up on. Those good genes are the ones that control the immune system, and doubling up on them is BAD. Every time a dog gets two copies of the same gene in this area, he loses some functionality of his immune system.

And guess what increases? Allergies, asthma, cancer, contagious diseases etc.

That's the problem.

HEALTH is not defined by genetic disease load. And it's a MISTAKE to foster that interpretation. Today's "treatment" of genetic disease is genepool shrinkage, and as we just realized, genepool shrinkage fosters major compromises to health.

When genetic disease load is the sole measure of health, people don't hesitate to breed dogs if they can give drugs to mask another condition (allergies etc.). Then they inbreed those dogs, just because they happen to be clear of the feared genetic conditions. This, of course, increases the real health problems.

Well, I feel like I'm just repeating myself over, and over, and over... so let's just sum up.

No, Ms. X is not saying don't do genetic screening. It has it's place, and it's place will become more important when breeders learn to manage environmental influences as treatment for genetic disease.

Ms. X is saying it's NOT responsible to say that health is measured with genetic screenings.

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