This is a quote from Frank Grover on the ADPEF.org web site on breeding. I thought it could open up some interesting discussion for those who wish to participate. Science has never created anything unless it was in a test tube. I don't want to live in a test tube.
I think it is important to understand first that inbreeding and line breeding are two totally different strategies and can't be lumped into the same sentence.Inbreeding is the mating of two very close relatives - ex. Father to daughter, mother to son, half brother to half sister. This is used when a new breed is being formed inorder to intensify the specific traits one is wanting to "set" in the lines. With that also comes some hidden faults that can be intensified. Once a line is set pretty much what is the the genetic mix is there to stay. That is why in the beginning you hope that there is a wide variety of dogs used to bring about the product you are looking for and that it reduced the negative as much as possible.
LineBreeding is a tried and proven strategy breeders have used with success for many years. It is the mating of more distant relatives ex: Grandsire to granddaughter, Uncle to niece and its goal is to produce more consistent litters. Back in those days dogs were very prepotent meaning the genes were so strong you could predict what they would be like as adults - Each line back then had very distinct charastertics and breeders bred to what they liked. Often you will hear a judge say a dogs is "very typy" and this is mostly due to line breeding.
If you look at the history of the Doberman's that were imported to America, breeders took these dogs and developed several specific "types" from the mix depending one which dogs they crossed. Back in the early 50's, 60's and even into the 70's we saw dogs that were very distinct in type and by looking at the dogs you could tell which kennel they came from because of the line breeding. This is what we call prepotent.
Linebreeding certainly has its place in the purebred dog world and breeders should know the lines and breed accordingly to produce the best dog possilbe while sidestepping the landmines. We must understand that by the very nature of the purebred dogs there is a certain genetic load that can't be avoided because in the end they all came from the same beginnings.
Each breeder has to determine for themselves how much they want to linebreed and how tightly. In all things consdered every breeder I have every talked with agrees you have to go outside to bring in new blood to keep the line strong and healthy without loosing what you have worked so hard to maintain. This is not new to breeders who have been breeding for a while and understand the whole picture.
The problem is today we have way too many johnny come latelys who have no real knowledge of what breeding is really all about or how it plays out and that to me would include the author of the above article. Scientist are not breeders and neither sicene or genetics in breeding always work out in a nice neat little package that would allow us to label linebreeding as a bad thing especailly if they lump linebreeding and inbreeding in the same catagory.