interesting read on line breeding - Page 3

Well, bubba, what you say may be true in your above post. But...have you ever tried to train a wolf to do anything beyond walk with a collar and leash attached? There's a good reason dogs are so varied in their appearance and capabilities....they are genetically malleable.....beyond that of any other species on earth. Pretty sure they would prefer humans don't disappear from their lives...we need each other.

The point is that when you inbreed you give up viability and fitness.  If you want to inbreed that is fine but all that you are doing is creating a human dependent species with a smaller tool set and less fitness and health for survival than the original population.

Human dependence comes with domestication. You know about pariah dogs? The Carolinas dog, the basinji , the dingo, the Ibizan hound, etc? Those are very inbred ( evidenced by the uniformity within the breed) and can survive without human intervention. In Florida years ago, packs of feral dogs had gsd in them. The point is, not using veterinary intervention for reproduction and not using unsound animals for breeding will prevent propagating inferior animals.

Inbreeding always has a price.  All dog breeds are inbred. 

My smooth fox terriers lived for fourteen, fifteen and sixteen years. The mother and her daughter, fourteen years, her two son's fifteen and sixteen. Not many breeds are more inbred than the smooth. The pups learned to hunt, catch and eat big grass hoppers when they were only four weeks old from their dam. She taught them to rat, and they would swallow a captured rat whole before the others could take it a way from them. They worked as a team digging out varmints such as possums and ground hogs. The largest male would go in for the kill as the sister dug into the burrow and reached the quarry....the dam always at the other exit preventing the prey from escaping. They hunted and captured prey that way every time...a system they worked out. So I have no doubt they would survive on their own. They all had beautiful white teeth through old age and were healthy all their lives. Maybe they were the exception, but I don't think so.

outbreeding depression is getting a lot of traction in field biology of wild species, seems to have the same negative effects that can come with inbreeding.

All one has to do is look at all the inbreeding that exists in hounds and pointers that still fulfill their purpose.

apparently the only way to maintain the argumernt is not to look.

"It's the mantra of the experienced breeder: "Know your lines." That is certainly good advice for the things that CAN be known, but there seems to be little appreciation for the fact that there are many things that you CANNOT know. The only way to manage the unknowns is by breeding in a way the manages the risk of finding out the hard way what those silent mutations are."

http://www.instituteofcaninebiology.org/blog/the-fiction-of-knowing-your-lines

There is no outbreeding in a dog breed with closed registration books such as the GSD which closed it's breed books nearly 100 years ago.  All GSD are inbred and even with no shared ancestor in 5 generations they all have shared bloodlines and go back to the original dogs which were producing offspring when the breed books were closed to new entries.  Mutations are part of the problem but many of the health problems are due to multiple allele methods of inheritance or incomplete penetrance as the geneticists like to refer to when they can't explain something.  Many diseases can be linked to extra copies of a gene occuring at the same site on the chromosome such that you have multiple copies of the gene building up with certain parentages.  In these copying error cases a single copy of the gene may cause no disease or health problem,  10 copies may also cause no problems, 40 copies may produce mild effects,  and 100 copies will result in a full blown expression of the disease or syndrome.  If the gene is silenced or has only a few copies at it's site on the chromosome it is nearly impossible to breed out such problems but inbreeding is not likely to make things better nor is linebreeding.  Thus the idea that inbreeding purifies the bloodline is a fallacy .. all it may accomplish is to eleminate one problem and replace it with one much worse.