The Need For Genetic Diversity. - Page 1

Whereas animals in the wild depend for their continued viability and health on instinctively observing severe selection criteria, the creation of modern dog breeds entailed close inbreeding on a few highly typical foundation animals. Subsequent practices, including the use of too few studs and ‘line-breeding’, only worsened previously inflicted genetic damage; leaving present pedigree dog’s condition in stark contrast to the better health and longevity of mongrels. Inbred animals became easily sick, were sterile or evinced any of a number of defects. Inbreeding was nonetheless viewed as a crucial tool for achieving breeding goals. Adopting ‘out-crossing’ methods solved most problems but also hindered breeding progress. And culling diseased and otherwise defective animals saw the more damaging genes removed. And if not plain benign, inbreeding was thus even said to be good for a breed’s general health! Invariably, a single dog exemplified sought-after characteristics to such a high degree that it became that breed’s sire of choice. This stud often proved to be a prepotent sire, improving the conformation for much of the whole breed. Its prepotency was largely illusory though: with little more to transmit than good looks and similar traits, such a sire mostly failed to transmit a host of other desirable genes. In biological terms he was not ‘prepotent’ at all, but in fact inferior! Then, folks often didn’t like a breed’s current look any more, with relevant standard expediently modified or simply re-interpreted by judges, clubs and breeders. And as mere descriptions, standards allow plenty of scope for arriving at different forms. In comparing old and new dog pictures, the very idea that these belong to the same breed, or fall within the same standard, variously stretches credibility itself! Adopting these changes required new selection criteria and more intensive breeding with the fewer dogs sporting the new features. These practices inevitably led to genetic depletion, chronically so in some cases, and its adverse effects persist even where at some later point less intensive breeding methods are adopted. Where close breeding didn’t initiate new disorders, it yet promoted their future occurrence. Years of inbreeding left high levels of certain defective genes in all breeds, causing in turn a galaxy of breed-specific diseases. For most pedigreed animals the number of harmful genes are few when compared to those carried by wild relatives, but in that a large percentage of breed specific dogs carry the same defects, their impact is that much greater. In the wild on the other hand, and insofar partnered male and female rarely carry simultaneously the same defective alleles, genetically sick individuals are equally rare. Genetic diversity, or variability (as driven by a vertebrate’s ‘major histocompatibility’ genetic web), not only imparts vital infection resistance and reproductive success, but also accounts for an animal's body odor, so serving as an infallible indicator of a male's genetic quality. Merely by sniffing, a female can establish whether a potential male partner is too closely related, or otherwise an adequate match (other wild species often rely on a variety of cues). Our dogs most likely lost this ability during domestication, although instances of female mating ‘delicacy’ aren’t completely unknown. Selecting for health and fitness boosts genetic variance, as it favors individuals that perchance retained a higher level of genetic diversity. Genetically variable dogs respond better to their environment, posses greater stamina and generally better performers, are more fertile, longer lived and healthier with higher disease resistance, and display superior intelligence and more robust spirits.

Speaknow you dont seem to know anything about nature, wild animals or the natural world.   I do think that you've figured out that mans not as smart as he thinks he is.      Diversity is certainly an important factor in the well being of any living thing.

You sure take the long way around the bush.    Many times over.

Jibber Jabber

 

It’s only a very short condensation of a piece by a highly renowned and respected scientist, Two Moons. Wish you’d detail your reservations more specifically – any idiot (which I know you’re not!) can sling off with a quick and mindless one-liners! Besides, judging by many of the questions posed on a variety of dog problems, many here don’t seem to have the foggiest about the vital role played by genetic diversity. Still, maybe you prefer this entry: Concerning ‘line-breeding’ or inbreeding generally, the dog world seems loath to learn from science. Line-breeding merely describes the inbreeding on animals a little further back in the pedigree than otherwise. Inbreeding eventually induces ‘inbreeding depression’, bringing with it reduced stress and disease resistance, fewer offspring, and shorter lives. It equates to a loss in heterozygosity and lowers the modern GSD’s working ability or utilitarian beauty. Scientific evidence irrefutably shows that artificial selection is variously deleterious, whereas natural selection furthers genetic diversity and dog’s overall health. Even for German breeders, who once prided themselves on keeping ‘open’ the more important sire lines no longer found in modern pedigrees, it has become almost impossible to source show-dogs not line-bred on Palme Wildsteigerland and the Q-litter Arminius. It is unremitting line-breeding which led to the immune system deficiencies in Lasso Neuenberg and other offspring, nagging high levels of HD in Zamb Wienerau descendants, low percentages of Körklasse-1 survey qualification in Tacko Wienerau’s and even for Sieger Lasso’s progeny. These merely represent the many similarly problematic dogs; and defects as these, including GSD dwarfism and various hemophilia, are the direct result of breeding to the same small number of studs and bloodlines, and of the failure to employ the necessary out-crossing. In fact, if German breeders especially don’t start tightening up on GSD hip and elbow joint quality, as well as generally broadening range of bloodlines used (working lines are almost as bad in this respect as show-lines), they’ll soon arrive at the same genetic dead-end as the American ones. The most common route to inbreeding is the widespread use of a handful of top VA animals to the exclusion of other good but less-highly placed competition dogs. It may improve likelihood of producing progeny displaying some of the more obvious (dominant or homozygous) desirable traits, but simultaneously adds the hidden, defective alleles. When breeders all flock to a few leading studs, these bad genes mount as well, while the good genes that an unused dog might have contributed are lost. These undesirable recessives will soon become glaring problems, impossible to ignore and hard to remove. Whenever possible, out-cross! And encourage the breed clubs to use genetic diversity (inbreeding coefficient) in recognizing the breeding worth of dogs and their lines. The above much shorter ‘re-hash’ is derived from a Fred Lanting Internet article, which in turn is an excerpt from his outstanding and highly acclaimed text The Total German Shepherd Dog.

I'm sorry speaknow,    replace speaknow with some scientist.  Now I understand why it was so hard to get thru.  

Your scientist is right about one thing,  a lot of breeders around the world dont understand what its all about.

Sorry about the one liner's,  I dont have enough wind anymore to type six paragraphs.

I agree with your scientist until the observations about what goes on in the wild.

It would be nice to know specific genetic weakness's of certain lines ,   but it would probably get deleted.

Oh well, I couldnt sleep last night and just happend in on the post.   Its been the topic of many post's before and will not be resolved by the mass's.    Maybe just a few.

as you may recall - there were a couple of threads some time back on the virtues of reintroducing dutch shepherd or malinois blood.  not well received.  i felt at the time, that folks were misunderstanding the entire concept.  we don't want to "lose" our breed in the process, but that is how they seemed to interpret it.

at any rate; i have to agree that the dogs have become pretty heavily linebred and we need to be looking at ways to weed out the problems and work on building a healthier, sounder dog.

pjp

yes, and just a few days ago there was mention of this fine dog on the awdf thread:

http://www.pedigreedatabase.com/gsd/pedigree/447368.html

 

he is titled in schh, ipo and ring.  i commented that he would be a good

candidate for both the working and show folks, yet the database shows

no idication of progeny.  while no dog is perfect, he certainly would offer

some diversity for some breeders.

pjp

In my mind one of the positives for adding Dutchie or Maly blood would be hips.  It doesnt matter the line...GSDs have hip issues...and crossing between the lines doesnt change that.  The former breeds dont have quite so rampant a problem.

Sometimes I wish the German Dog people where more like the German Horse people.

~Cate