Answer:
Not only must they be purebred but must be registered with the AKC and have their AKC papers.
yes
rw777999@gmail
Unfortunately The last time I checked the AKC did not have a rule regarding In-breeding or Line-breeding. Many breeders do this so when you look at those AKC (worthless ) papers it looks like there is a lot of champions in your dogs background.
Many dog breeders have been caught for obtaining AKC papers by using a dead dogs papers. Many more breeders have not been caught.