But creating any new breed, as in an actual breed rather than crossing mutts that will produce a variety of offspring, usually involved significant inbreeding.

But creating any new breed, as in an actual breed rather than crossing mutts that will produce a variety of offspring, usually involved significant inbreeding. You need to weed out the genes that you don't want and concentrate on the few that define the breed in order to create a homogenous stock. Otherwise, in a couple generations the new offspring may pick start expressing the recessive genes and be nothing like the originals.