Given what I understood about the history of dogs and the methods used to create breeds, the question for me was:
How do I combine the traits I want so they breed reliably without using inbreeding? Is there a way to do it that reverses the unwanted effects of inbreeding? How does life do it?
Breed and select for dominance.
Instead of maintaining recessive traits, reduce them. If I don’t require recessive characteristics I don’t need to inbreed because I won’t lose the dominant traits I’ve previously combined when I outcross the dog, they will still be expressed. Breed in a way that combines and stabilizes the genes I want and diversifies the characteristics that I’m not concerned about.
The basic pattern I use to accomplish this is: outcross -> linebreed -> outcross -> linebreed -> …
Huge advantages to building on this strategy are that every generation results in an improvement over the parents. No generations are required to maintain a combination of recessive characteristics. And dominance results in a high percentage of the pups displaying the traits you are after, so their characteristics are more dependable and litters are more uniform.
Also I am outcrossing to different breeds which significantly increases the genetic diversity in the characteristics I’m not maintaining.
My main obstacle was how to get the size down because my observations were that the smallest dog from a mixed breed litter was about the same size as the smallest parent and the largest was close the the height of the larger. Hubbub was the anomaly I was after. Smaller than either parent, I believed she had a pair of genes that have a dominant effect on height which meant I did not have to inbreed to get litters where every pup stayed under 16″ (40cm). I also felt her littermate, My-My, may carry one of the gene pair. I began by outcrossing Hubbub to a Border Collie / Staffy cross and My-My to a Whippet. One of Hubbub’s puppies, Fox, was the same size as Hubbub, which meant it was probably a gene pair. Then I linebred the offspring, Fox from Hubbub with Eagle from My-My and got a 14″ male, iPod, which verified that this height gene combination would allow me to exclude inbreeding.
Breeders of the purebreds I selected for the foundation of my lines have discovered the best genes for the physical characteristics that I’m after, and the reason that I don’t need to inbreed is that they have already done it for me. I want the same characteristics that would make a dog successful in its natural environment so all of the traits I’m after have already become dominant through natural selection except height. I assumed that the genes that create the quickest dog are the most dominant and genes for endurance are less dominant because quickness would be an advantage in the environment they evolved in. Selecting Whippets as the quickest breed means I get both the best genes possible for speed and the most dominant. Selecting the Border Collie for awareness results in the most aware pups possible because awareness has acquired dominance through selection in the wild and breeders have found the best gene for that. And when I cross our Whippet mixes to our Border Collie mixes I get both quick and aware offspring. I’m not putting Humpty Dumpty back together again, I get to use turbo-charged parts, the best genes available, thanks to the collaborative work of the purebred breeders.
For my purposes I selected for traits that would result in companion dogs that would excel in sports. If I were breeding for a different purpose I would select different breeds for my foundation. But even if I were breeding purebreds, I would still incorporate this strategy as much as possible, and I would still be focused on the dominance heirarchy of traits inside of that gene pool.