I don't think you articulate yourself well. Here is what you said:
"I will explain with dogs. Choosing 2 or more breeds of dog you select them for the traits you want in your purebred race that you wish to create and maintain. Then you breed them and continue to breed thier offspring only amongst themselves. Through inbreeding over generations you create your purebreed. To maintain this line you must continue this inbreeding (even if with non blood descendants from the creation of this breed from multiple hosts it is still inbreeding to a degree because of the limited genetic beginnings) and in time the breed develops genetic flaws. So to purify your race would be to set out to flaw it and the "pure blood line" began with the combining of other breeds. "
In context, I detailed its implications.
"I will explain with dogs. Choosing 2 or more breeds of dog you select them for the traits you want in your purebred race that you wish to create and maintain. Then you breed them and continue to breed thier offspring only amongst themselves. Through inbreeding over generations you create your purebreed. To maintain this line you must continue this inbreeding (even if with non blood descendants from the creation of this breed from multiple hosts it is still inbreeding to a degree because of the limited genetic beginnings) and in time the breed develops genetic flaws. So to purify your race would be to set out to flaw it and the "pure blood line" began with the combining of other breeds. "
In context, I detailed its implications.