In most cases, a successful combination is only appreciated when it can no longer be reproduced. At which point, most breeders wish they had the ability to go back in time and do things differently. As most breeders generally collect semen from important males and not cryogenically frozen embryo’s from exceptional producing females; they must first compound on the desirable traits, they wish to reproduce.
A dedicated breeder’s sole objective is to progressively move forward, whilst still preserving the genotype (internally coded, inheritable information) and phenotype (outward, physical manifestation) within their bloodline. He is not persuaded by external influences, such as financial gain or religious beliefs; but only towards the desired objective, in a calculated breeding program.
Producing a bloodline is all about selection. The major benefit of inbreeding is that it exposes undesirable traits within that particular bloodline. This enables the breeder to eradicate those undesirable traits from that bloodline through prudent culling. By culling the offspring that have inherited the undesirable traits and continuing to inbreed from the most balanced females, the breeder will eventually remove the undesirable traits from that bloodline. Once they are removed, they will not remain dormant to reappear, generation after generation.
A family bloodline can only be produced through inbreeding, not out-crossing. Out-crossing dilutes desirable traits and does nothing to rectify the faults within that particular combination. It only masks the faults, which will reoccur in future generations. When a breeder inbreeds (father to daughter, son to mother or brother to sister) they are essentially compounding on the good and bad traits to expose them. After several generations of inbreeding, a breeder will begin to produce a family bloodline. This is the only proven method of re-producing desirable traits, with enough potency, to have a sufficient effect on successive generations.
If you would like to comprehend the level at which a family bloodline is considered isogenic (having the same or closely similar genotypes) this small paragraph from the worlds foremost laboratory the subject, will be very difficult for most canine breeders to accept.
Breeding Strategies for Maintaining Colonies of Laboratory Mice - author, JAX - The Jackson Laboratory, Relatively Simple Breeding Schemes
“A strain is defined as inbred if it was produced by sibling matings for more than 20 generations, after which all mice are considered isogenic or genetically identical. To remain inbred, a strain must be maintained by sibling matings or, if necessary, by parent-off spring matings. The main pedigree line should be derived from a single sister-brother breeding pair at each generation."
Yes, they did say a minimum of "20 generations" of full brother-sister matings.
In order for a trait to be present in the next generation, it needs to come from both parents. If the sire and dam both carry the same trait, it “may” be concentrated enough to carry onto the next generation. That is why, full brother-sister matings are the key to success; because both sire and dam carry many of the same hereditary traits. They may not be physically present, but they have a lot higher percentage of carrying onto the next generation.
If you would like to reproduce the desirable traits, a particular male possesses; do successive father-daughter matings. If you would like to reproduce the desirable traits, a particular female possesses; do successive son-mother matings. When you believe you have compounded on enough of those desirable traits; inbreed continuous brother-sister matings to lock in those desirable traits. It’s really that simple. When you see undesirable traits in the offspring, cull and continue forward. After several generations your bloodline will begin to become isogenic. It took me twenty years to fully understand this concept and for the first time, I am able to explain it to you in one simple little paragraph.
It is highly recommended that you produce a second family bloodline, to protect you’re initial family bloodline, from unforeseen complications. From the original dam you commenced your full brother-sister matings; inbreed a continuous father-daughter combination with an unrelated male. I recommend a triple father-daughter combination at a minimum. When you see uniformity, in both phenotype and genotype, begin the continuous brother-sister matings. It is very important that you keep the two independent bloodlines, completely separate from one another, until there is a clear indication that they are isogenic.
Regrettably, that is where almost every breeder fails. They cross the two independent bloodlines together and discontinue with the original bloodlines and create a hybrid vigor out-cross; because they "appear" to be better. But they never reproduce successfully, for their lack of consistency.
We endeavour to be the first KNPV Dutch Shepherd breeder to replicate the breeding practices outlined above, from the world’s foremost laboratory the subject. I would like to say a very special thank you, to our friends in the Netherlands for making this possible.
Line-breeding versus Outcrossing
A very liberally edited version of an article by Jerold S. Bell, D.V.M. that appeared in the September 1992 American Kennel Club Gazette, "The Ins and Outs of Pedigree Analysis, Genetic Diversity, and Genetic Disease Control" ... followed by some personal observations.
Without exception all breeds of dogs are the result of line-breeding. Line-breeding has either occurred through natural selection among a small isolated population (i.e. the dingo) or through the influence of man, breeding selected animals to derive specific traits. Either way intensive line-breeding is responsible for setting enough of the dominant traits that the resulting group breeds true to type. At which point a population of dogs can be said to be a breed.
Dogs actually have more genes than humans. Tens of thousands of genes interact to produce a single dog. All genes are inherited in pairs, one from the sire and one from the dam. If the inherited genes from both parents are identical they are said to be homozygous. If the pair of inherited genes are not similar, they are said to be heterozygous. The gene pairs that make a German Shorthair breed true to type are obviously homozygous. However, variable gene pairs like those that control coat color, size, scenting ability, etc. are still heterozygous within the breed as a whole.
Line-breeding concentrates the genes of a specific ancestor or ancestors through their appearance multiple times in a pedigree. When a specific ancestor, appears more than once behind at least one ancestor on both the sire's side and yet another on the dam's side, homozygosity for that ancestor's traits is possible.
However, if this specific ancestor appears only through a particular offspring of the ancestor in question, then the breeder is actually breeding on the offspring of the ancestor, rather than on the ancestor itself. This is why having many "uncovered crosses" to a specific ancestor (those that come through different offspring of the specific ancestor) gives the breeder the greatest chance of making the desired traits, of the specific ancestor homozygous.
Homozygosity greatly improves the chances that the resulting pups, will in turn pass on the desired traits of the specific ancestor, to their pups. When selecting pups from a line-bred litter the breeder must choose pups that display the desired traits of the specific ancestor, or they have accomplished little. In fact, if these traits are not present in a line-bred pup, it is very likely that it inherited its genes from the remaining part of its pedigree and will be unable to reproduce the desired traits.
Line-breeding significantly increases homozygosity and therefore uniformity within a litter. One of the best methods of evaluating how successful a line-breeding has produced, is to gauge the similarity of the littermates as compared with pups of other litters, with similar pedigrees. Considerable similarity among littermates tells the breeder the genes have paired together as anticipated. The resulting pups will likely be able to pass those genes onto the next generation.
Undesirable recessive genes are always masked by a dominant gene. Through line-breeding, a rare recessive gene can be passed from a common ancestor, on both the sire and the dam's side, creating a homozygous recessive offspring. The resulting offspring actually displays the trait, neither of their parents displayed, even though both of them carried it.
Line-breeding does not cause good genes to somehow mutate - it only increases the likelihood that existing genes will be displayed - allowing the breeder the chance to eliminate what had previously been unseen in their particular line, although it was always present.
Too many breeders outcross as soon as an undesirable trait appears, blaming the problem on breeding "too close." Nothing could be further from the truth. In fact out-crossing insures that the undesirable trait will be carried, generation after generation, in a heterozygous recessive state; only to reappear again and again. Therefore the breeder who turns away from line-breeding, is simply passing a known problem onto successive generations and future breeders.
When an undesirable trait is exposed, the breeder who does his breed a real service, is the one that stays with his line long enough to rid it of the undesirable trait. By controlling which specimens within his line are used for breeding, he can eliminate the undesirable trait. Once the recessive gene is removed, it can no longer affect the breeder's line.
Novice breeders don't realize that individual dogs may share desirable traits, but inherit them differently. This is especially true of polygenic traits, such as ear set, bite, or length of forearm. Many breeders fail to understand that breeding dogs which are phenotypically similar, but genotypically unrelated, won't produce the desired traits in the current litter; and will actually reduce the chance of these traits being reproducible in successive generations.
Line-breeding must be made on a combination of performance, appearance and ancestry. If a breeder is going to be successful in solidifying a certain trait, they must rigorously select their breeding specimens, which display the desired trait. In doing so, the breeder has a chance of making this desired trait homozygous over time. This is the key to successful line-breeding that is most often missed by unsuccessful breeders.
This article was originally written in the 1930s by Dr. Kleemann, by whom the German Kleemann Seiger or KS tests were developed and for whom they are named. It was first reprinted in the Kurzhaar Blatter in August of 1962 then subsequently translated into English and reprinted in the GSP News in 1963. Dr. Kleemann was deceased for 20 years, when this article was first published. We owe a great debt to Dr. Kleemann, for his ability to put his keen observations in writing, for the rest of us to follow.
In all mammals the females are "X" "X" and males are "X" "Y" which means that only females carry the genetic code particular to the part of the gene string that is missing in all males. Horse Breeders refer to it the "X Factor" and have demonstrated that the gene responsible for the large heart so many great racing stallions have, can be traced back thru their mothersline, to a single mare that lived more than 100 years ago. If a stallion has an oversized heart - like Secretariat - this particular mare will show up in his mothersline. The mares themselves don't have the large heart, but they carry the gene for it on their “X” chromosome. Likewise the stallions do not throw the large heart themselves.
Females are far more important than males, in carrying particular genes forward. Understand that this is true, even if the genes most sought after, were originally found in a pre-potent male. The key for any successful breeder, is to isolate those females that carried his traits and breed off, of them. It has been our experience that many important traits are indeed sex linked and carried by the dams from generation to generation.
Successful breeders realize they are fighting "the drag of the breed," which is the tendency for all animals to breed back toward mediocrity. If it didn't work that way, super species and super races, would have developed long ago in every animal on earth. For instance in human beings, it is impossible to breed parents with high IQs together to produce higher IQs. Even when two geniuses have children, the average IQ of their children will be half way between normal and the average of the parents IQs.
By the way, Einstein himself was the offspring of parents who were themselves first cousins and he married his first cousin. So much for the stories you heard in school about the effects of line-breeding.
What is the meaning of "mothersline". The idea is too often confused by breeders with "motherside" or the bottom side of a pedigree. The mothersline is the whole of the bloodlines of all the mothers, including the father's mother and the other mothers on the father's side of the pedigree; but always the mothers.
The success of breeding on the mothersline comes from utilizing very important sex-linked genes, present only in the additional DNA of the X chromosomes of great producing females. Since a male canine has 76 paired chromosomes (plus an X and a Y chromosome) the only place a male can inherit those important sex-linked genes, is through his mother. Therefore, when that son becomes a father, only his resulting daughters (never his sons) get this valuable X chromosome back again, along with another X chromosome from their own mother.
In turn, when these resulting grand-daughters become mothers, the art of breeding lies in selecting the male offspring, that has inherited the valuable X chromosome. As these great-grandsons, will be able to pass the important sex-linked genes onto their offspring and transfers the influence of the particular female, through this valuable X chromosome, to the topside of the pedigree. Which dramatically improve the chance of reproducing great pups true to type, when a breeder breeds to quality females from the original female’s bloodline. The importance of having an unbroken mothersline on both sides of the pedigree is paramount.
Pedigrees only serve as a guide, to show what traits, may be carried by certain parent. Only through careful study of a particular parent’s offspring and intimate knowledge of its ancestors; can a breeder determine what traits, they actually carry. Furthermore, it is necessary to breed, on both bloodline and performance, to achieve success.
Thru line-breeding, a breeder can double-up on good and bad traits. Which gives the breeder an insight to what traits they are dealing with? When faults in the bloodline come to the surface, the breeder can eradicate those faults from his breeding program. By out-crossing, the breeder only covers-up the faults and reduces his knowledge of what to expect in subsequent litters. Anyone who condemns inbreeding must in turn condemn the detective, who exposes a crime.