How about line breeding?
Line breeding is when the sire and the dam are distantly related: e.g., grandsire to granddaughter, granddam to grandson, second cousins, half cousins, uncle to niece, aunt to nephew….. The general strategy is that there is a common ancestor that is being doubled up on both sides. So the desired dog appears several times in the pedigree.
This is probably the most common strategy in breeding purebred dogs (and in developing new breeds, for that matter). Though this method, new genes are slowly introduced and unwanted genes are slowly replaced. The actual rate varies by how strongly you line breed. It sacrifices little overall quality in terms of show quality. Usually the puppies are rather close in general conformation. The only problem with this method is that it often takes several generations to get poor genes out, (or adding desired genes in) resulting in many puppies that have the same genetic problems (or virtues) that their parents have. And then because some breeders are more interested in winning, they do not place the affected puppies on spay/neuter contracts. This is both a blessing and a curse for the breed. If the breeder is very careful, affected pups can be used wisely to prevent loss of quality, but still remove the affected genes by only breeding the affected pups to known non-carrier relatives. This way the breeder can again try to “edit out” the bad genes. It takes longer this way but less show quality is lost in the process. This process results in dogs that will often reproduce their same level of quality. This is referred to as reaching homozygous litters (more genes of the same kind apparent in the puppies).
Inbreeding and linebreeding really differ only in degree. Linebreeding is less likely to cause harm than inbreeding. Inbreeding is not for novices. Knowledge of genetics and the breed is required for success. For good results it must be well-planned and breeders must be ready for whatever problems it presents.
Wilcox, Bonnie (DVM). “Things to Think about Before Breeding Your Dog.” DVM, printed in various newsletters.
