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inbreeding diversity pedigree linebreeding genes genetics dog crossbreeding outcrossing animal husbandry Fred Lanting

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INBREEDING AND DIVERSITY - PART 5

by Fred Lanting

Copyright January, 2009 -

Continued from PART 4

The lower cells can be filled from the upper cells.  The entries in this table are relationships between the individuals in the pedigree, as we have seen before.

We can construct from this table a second one that contains the breed composition, in terms of outcross percentage, between matings. In the following table, the entry 2-3, for example, is the percentage outcross in a mating between a second and a third generation animal.  The value is computed as ½ (ROutcross-2 + ROutcross-3), where the RXY are taken from the above table.

The table entries are presented as decimals rather than fractions because it is easier to read off values that way. Our intuition tells us that as time passes, the influence of the outcross upon the breed will diminish, and this is confirmed by the table above. There is no column or row corresponding to the outcross because only one outcrossing event was permitted in the outlined breeding program. When reading this table it must be noted that these matings are based on the assumption that the outcross event occurs only once in each animal’s pedigree. If there has been inbreeding in the population, the correct table may be computed from the appropriate table of relationships.

It is up to the individual breed associations to establish standards for breed composition, but we can provide a tool for studying possible rules.  The following table is an excerpt from the second table above.  The shaded portion of the table represents matings that are not permitted by the proposed breed association rules presented earlier.  We are interested in answering the question: “Are these rules based on sound scientific principles?”

Our answer is a firm “No.”  We can assume that the reasoning behind the mating rules was to limit the influence of the outcross and preserve distinct breed characteristics.  One way to do this is to limit the number of times the outcross may appear in an individual’s pedigree.  The obvious problem here is that there are permitted matings with levels of outcross composition much higher than some of the forbidden matings. This is quite obvious when considering the 2-5, 2-6, and 2-7 combinations.  A more reasonable approach would be to limit the percentage of outcross, and not issue papers if that limit was exceeded. Such a decision might have to wait until there are several matings of each combination to determine if there is a natural threshold between acceptable and unacceptable levels of composition. We would recommend the establishment of an arbitrary criterion at the beginning of an outcross program that would be reevaluated at set points in time. For example, it might be decided that the outcross percentage should initially be limited to 15% or less. After four generations including the outcross, that level might be changed to 10% or less based on observations of composite individuals.

Outcrossing can be used to great benefit when a population is having a hard time maintaining a healthy breeding population.  There are procedures, outlined above, for determining the outcome of specific matings to outcrossed individuals that can be used to establish breed rules for purity.  There are no hard and fast rules for what those breed regulations should be.  What can be stated strongly is that breeders should not be afraid to use outcrossing as a management tool.  A healthy, vigorous dog is much more desirable than a “pure” one.

Putting it all Together

We have discussed some important ideas and introduced some useful tools for the dog breeder in the preceding sections.  We will now conclude with a discussion of how to design and manage an effective breeding program.  It is not enough to simply mate good animals to one another and hope for the best, especially when such important traits as show-ring success are very strongly influenced by environmental factors.

Bourdon (1997) discusses what he called common sense animal breeding. He emphasizes traits common to effective and successful animal breeders that bear reiteration here.  Qualities desirable in a breeder include knowledge of theory and technology, patience and deliberation. The most important tool used by the careful breeder is good information. Finally, a good breeding program is characterized by consistency and simplicity.

Technical knowledge is important for an animal breeder.  To be most effective, he must understand not only the methods he uses, but also something of the theory behind them.  One does not have to be a mathematician or statistician to effectively breed good dogs, but should have a command of certain fundamental knowledge. The breeder has to understand the idea of Mendelian inheritance, for example, before he can properly understand how methods of computing inbreeding and relationship work. Another important concept to master is that genetic inheritance is a random mechanism that presents both opportunities and limitations. When the knowledge is available, the breeder should be aware of positive and negative genetic correlations among traits under consideration. If height is negatively correlated with litter size, and you are interested in fecundity, you should choose the short dog.  Genetic mechanisms will not change for our wishing them to. Familiarity with the current publications and interaction with other animal breeders is very helpful in acquiring and maintaining technical knowledge.

While patience appears second in the list, it is perhaps the most important characteristic of the successful breeder. Genetic change occurs more slowly than many of us might like, but the trade off is that genetic gains are cumulative. The random nature of gene segregation makes much of inheritance unpredictable, so the wise breeder will play the averages. Adherence to a well-defined breeding program will produce successive generations that are better than their predecessors. Most offspring produced are considered average, but occasionally a truly outstanding individual will be produced. That individual should be patiently sought after, recognized and exploited.

No breeding program can succeed if it does not have clearly considered and realistic goals. The deliberate animal breeder will spend time thinking about his goals, his definition of the ideal animal, and the best way he can obtain animals with desirable characteristics. The temptation to jump on the bandwagon and follow the lead of other breeders should be resisted. A thoughtful manager will always know more about what is best for his program than anyone else.

The importance of good information cannot be stressed enough. Data about his animals is the single most important commodity any animal breeder possesses. Dog breeders do not have access to the kinds of information many livestock breeders do, typically genetic evaluations based on vast amounts of data and complex statistical analyses. Look for the most meaningful available. If pedigrees are the basis for most of your decision-making, do not accept incomplete or suspect pedigrees, and deal with “seedstock” producers (breeders) known to you to be of superior integrity and knowledge.

The nature of the information collected is also of interest. If it is not economically unfeasible, things like litter size, birth and mature weights and body dimensions should be collected, recorded, and contributed to breed databases. It is no disadvantage to breeders to share their hard-won information with others. When good quality data is available to everyone, the whole breed benefits. An example of the importance of collecting and sharing information might involve the discovery that a given line was a carrier for a deleterious recessive. The recognition of the problem would lead to breeders making more informed decisions about matings, particularly matings involving relatives. While the goal of a breeding program is the production of animals as close to ideal as possible, it does not relieve breeders of the responsibility of considering animal welfare.

The quality of information collected is of seminal importance.  It really does not matter if there are thousands of records in breed books of they are not accurate records. You cannot make rapid genetic progress without sound information on which to base your breeding decisions.  If you are faced with a tradeoff between the quality and the quantity of records you can record, always choose high quality. 

The breeding program itself should be simple and consistent. By simplicity we mean that goals are carefully thought out and are reasonable in light of the information available and the genetics of the traits under consideration. Consistency implies that once goals are formulated, breeding strategies that lead to those goals are followed rigorously. That is not to say that there is no room for change in a breeding program; there is simply no room for hasty or ill-considered change. Frequent changes in breeding goals often result in contradictory efforts that lead nowhere fast. Clearly the patient animal breeder is better able to stick to goals once they have been established. 

It can be difficult to formulate simple goals. There is often a temptation to try and improve several characteristics at once. Sometimes there will be positive correlations between traits of interest, and progress can be made in more than one area at once.  However, you cannot change everything at once. There is a classic rule in animal breeding that states if you select for n traits, progress will only be 1/Ön (one divided by the square root of n) as rapid as if you select for a single trait.  If you select for two traits, you only make 71% as much progress as if you selected for a single trait, and 58% as much progress if you select for 3 traits.  The old maxim of “keep it simple” should always be borne in mind.

While there exists no absolute set of rules to guarantee your breeding program is successful, there are general rules to play by. You should always thoroughly understand the goals you are trying to attain. You should understand as much as possible the genetic mechanisms underlying the traits you want to select for. And you should understand that there is, and there will always be, a lot of luck. You cannot change the rules, but you can stack the deck in your favor.

MORE ON INBREEDING

The dog world seems unwilling to learn from science in some respects, and inbreeding-linebreeding is one of those areas. I say “one” because there is no real difference or dividing line between the two terms; linebreeding is simply descriptive of inbreeding on animals a little further back in the pedigree than otherwise. Laboratory rats and mice have been consistently inbred to a great degree in order to be more predictive about the effects of medicines and other things that experimenters are working on. But such scientists keep several different families going at a time, because they know that restricting the gene pool also has adverse effects sooner or later, and when a line starts to die out because of inbred weaknesses, they can cross with another family or more, and start a new line again. In time, inbreeding results in “inbreeding depression”, with such signs as smaller size, less resistance to stress and disease, fewer offspring, and shorter lives. Doesn’t that sound awfully familiar to those of us who’ve been watching the American GSD develop over the past 40 or so years? Except for the smaller size, perhaps, but those wouldn’t reach the mainstream of the market anyway. We dog breeders do not have the ability as individuals or associations to maintain dozens of separate bloodlines as the lab mice breeders do.

The more research into inbreeding and genetic diversity is carried out, the more evidence seemingly mounts that artificial selection can be deleterious and that natural selection results in a much broader diversity and therefore a greater health safety level. Even in Germany, where breeders formerly prided themselves on keeping “open” at least important sire lines that went back to dogs not found as often in modern pedigrees, it has become almost impossible to find GSD “show” dogs that are not linebred on Palme WildsteigerLand and the Q-litter Arminius. As a result of moderately strong linebreeding, we find such problems as the immune system deficiencies in Lasso Neuenberg and others’ offspring, nagging high levels of HD in Zamb Wienerau descendants, low percentages of Körklasse-1 (or even Kkl-2 for that matter) in Tacko Wienerau and even Sieger Lasso offspring. These are not prejudicially singled out; they are too representative of many dogs in the same boat. When “everybody” breeds to the same small number of dogs or bloodlines, these types of weaknesses are what you’ll get. On the other hand, some of Germany’s greatest GSDs came from brother-sister breedings whose papers were falsified in order to register the offspring.

The loss of diversity of genes is directly responsible for much of the genetic problems we see in many species of domesticated animals, not only dogs. Some breeds of swine, for example, almost have to be slaughtered by the age of 5-7 months to take advantage of the best ratio of sale price to feed cost, but also to avoid the almost inevitable hip dysplasia in those breeds. Only a few of the better-hip pigs or those on a less accelerated diet are kept long enough to breed from. If the Germans don’t start tightening up on GSD hip and elbow joint quality, and loosening up on the narrow focus of the bloodlines used (working lines are almost as bad in this respect as show lines), they will soon paint themselves into a corner the way the Americans have. Inbreeding depression walks hand-in-hand with loss of heterozygosity and the lower utilitarian beauty of the modern German Shepherd Dog.

The name “Border Collie” in the U.S. and a few other countries, was until recently in the same position the GSD was a hundred years ago, more a description of its occupation than its ancestry. Thanks to the self-serving and wrong-headed approach of the AKC, the Border Collie has become a “breed”, with all the dubious rights and appurtenances thereto granted by the AKC, including severe restriction of genetic diversity. This true working breed is beginning to find itself in the same position the Akita has been in for all those years the AKC refused to open the stud book to imports from the country of origin. The Akita has a host of health and temperament problems as a result. New “rare” breed clubs have formed in the U.S., partly to satisfy the desire for novelty, partly as a haven for those fleeing the more established breeds after disappointments in genetic health. But that’s jumping from the frying pan into the fire.

The “Shiloh Shepherd”, a new breed (30+ years in the making so far) is basically a GSD family chosen for large size, old-fashioned level-back stance, and allowable profuse long coats. To bring in the desired qualities that the founder couldn’t find enough of in the regular GSD, fanciers reportedly have brought in a couple other breeds in very small quantities. Still, the gene pool is extremely limited, and unless there is use of strict selection techniques for eliminating HD, dentition faults, and a few other problems, the breed will continue to have all the traditional inbred-GSD disorders plus a few more. The white GSD, recognized by some registries as a separate “breed” such as White Shepherd, White Herder, and other names, likewise has a number of structural and other limitations and is at moderate risk of genetic disease taking it over because of its relative lack of genetic diversity. The Chinook, based on a single big yellow dog of mixed Saint Bernard and other heritage, is being modeled into a more or less consistent Type by the “national” club via the use of “imported” genes from Siberians, Shepherds, and whatever results in the desired body style and personality characteristics. The English Shepherd is being pulled in two directions by those who want to breed for style and to show in conformation, and those who want to leave it as it is (a tremendous variation in appearance from an Australian Shepherd to Border Collie to almost a Leonberger look); the latter stress its farm and pet utility instead of pedigree. Whether “new” or not, breeds on the edges of what some consider “purebred” are faced with the challenge to keep enough diversity to prevent problems from becoming so deeply imbedded in the gene pool that there is almost no correction possible.

Today, almost all black Poodles (and their genetic diseases) are bred on the Wycliffe line.  Poodles are numerically among the worst afflicted with epilepsy. Dalmatians have a sack full of genetic disorders, and when the AKC and others proposed a scheme to rid the breed of hereditary deafness by judiciously blending a few Pointers into the breed, then culling to preserve Dal type while eliminating carriers, the Dalmatian club rebelled against logic and voted to stay on the course to self-destruction. Many feel that the Siberian Husky is a genetic mess because of the restriction to breeding only “pure” ancestry; they can’t work as well as sled dogs as can the mixed breeds which constitute the “Alaskan Husky”. Some 80% of Doberman Pinschers are either affected by or carriers of the genes for von Willebrand’s Disease (vWD), which means that those fanciers are in a real bind, as elimination of all those dogs would mean disaster for the breed. Copper toxicosis in the Bedlington; elbow dysplasia in the Rottie; PRA in the Irish Setter and Lab; PFK enzyme deficiency in American Cockers, English Springers, and Basenjis; dwarfism and hemophilias in the German Shepherd Dog, and many other examples of genetic disease are linked to the decrease in outcrossing over time. Germans for the most part still echo the official (but untrue) line that Canto was not a Type-A hemophiliac, and for a long time many of his GSD descendants suffered from that disorder; fortunately it is sex-linked so that only daughters are carriers of the recessive and sons tend to die early, and it has not been seen in recent years to be a major problem.

The canine has what is known as a very “plastic” genotype. What this means, in plain language, is that there is so much “automatic” crossing-over and slight mutation in the species, that diversity continues on its own to some extent, probably more than in most other species. Breeders typically fight against this when we practice selection for desired traits. However, it may be good advice to outcross whenever possible. And encourage the national breed clubs to use genetic diversity in recognizing the value of the dogs and lines. To quote an Internet/e-mail message on the subject, we all should take a closer look at “the dark side of inbreeding — what happens when everyone breeds to Mr. Wonderful, and what to do when everyone discovers they have the same problem.” (Genetic Diversity Project, Dr. Catherine Marley and Dr. John Armstrong). University of California-Berkeley canine genome researcher Jasper Rine sums it up: “There are just crazy levels of inbreeding in many breeds of dogs”.

One common route to inbreeding is the widespread use of a single popular “Grand Victor” or “Sieger” (national top winners), or a handful of top Award-of-Merit/Select animals to the exclusion of other good but less-highly placed competition dogs. While you may be increasing the chances of getting a dog that has some of the same obvious (probably dominant or homozygous) desirable qualities, you are at the same time increasing the concentration of so far hidden recessives, many or most of which are bad for the breed. When most people flock to the leaders for stud service, these bad genes are concentrated as well, and the good genes that an unused dog could have contributed may be lost forever. The undesirable recessives previously hidden in the lines will soon become glaring problems, impossible to ignore and difficult to get rid of.

The subject of inbreeding’s advantages and disadvantages will always be discussed with conviction and fervor, since there are strong arguments on both or all sides. I have had exposure to the practices of dairy cattle production, and have seen there an amazingly high COI. If a cow is a champion milk producer, her eggs are harvested after being fertilized with sperm from a small number of equally selected bulls, and transplanted into other heifers so she becomes “the mother of all cows”, to modify a popular phrase of the Iraq invasion era. Generally, dairy cows of whatever breed are extremely inbred, far more than dog breeders can possibly imagine.

In dogs, besides the rare-breed examples given earlier, allow me to direct your attention to two greatly different philosophies. I have been a dog judge (approved for a few hundred breeds) for many years and many countries, and have discussed breeding practices and theories with innumerable people of a wide range of expertise and backgrounds. In the American Pit Bull Terrier breed, I was an official inspector for the UKC and the NAPBTA, and in reviewing thousands of this breed and hundreds of pedigrees, I saw about the highest amount of inbreeding of any breed. I have also long judged the Jack Russell Terrier and its “first-cousins” (breakaway or splinter clubs use different names for their variety of this British breed). John Cargill, an astute researcher and a member of the JRTCA (“the largest Jack Russell terrier club in the world”, he says), reports that “genetic diversity is mandated. Under JRTCA rules, a dog cannot be registered if it has a Coefficient of Inbreeding of 16% or greater (not a particularly low COI).” In these breeds, I have observed no real difference in genetic deficiencies and general vigor and health. Even the notorious problem of missing teeth in the (very high-population) APBT seems to be as prevalent in “outcrosses” (when you can find such!) as in the most highly inbred specimens. Selection and culling are effective equally, in both breeds with opposite inbreeding philosophies.

Generally, if you are willing to cull (select) strongly at the beginning of a family development, you can be as successful as one GSD line I mentioned, or the typical dairy cattle breed population. The main problem is that most breeders are not that lucky, careful, or willing to select and cull.

END

General info on The Sieger Show Experience with tour guide Fred Lanting 

The  SV Bundessieger-Zuchtschau (BSZS or Sieger Show) in Germany is generally held in the last week of August or first week in September at a different location each year, depending on stadiums available. (The cost of stadium for this one-weekend event, and the competition with soccer/football events that sign contracts for many per year, determine the choice.) For the past 20 years or so, I have offered my non-profit 6-7-day guided tour of the show and sightseeing, including visits to kennels and training clubs. Get an SV judge's perspective of the bloodlines and procedures, along with experienced introductions to Germany's culture and beauty. My groups come from all parts of the globe, so even just the companionship is like a world-travel experience. We usually arrive on the Wednesday or Thursday before the show, and return the following Wednesday.

Looking for a great dog-related experience combined with seeing a different part of the world? Whatever your breed or activity in dogs, the annual Lanting guided show-and-sightseeing tour could be the experience of a lifetime. Read my annual “Impressions” articles on various websites for an idea of what we've seen in recent years. Tours centered on other countries’ Sieger Shows, the BSP, and world Schutzhund trials are also available if enough people sign up.    

None of "my people" have ever been sorry, and all have wished they had done it earlier! You will see the best of the breed, meet important GSD people, sometimes see another country or two, and have the over-all greatest dog show experience of your life. I also include, if you decide to join us, a variety of travel tips. I offer an SV conformation judge's perspective of the show (I also have AKC, UKC, and foreign judging experience). One year, when a travel-agency tour leader again deserted his group, they came to where my group was sitting and asked me questions. References available from previous tour participants. Testimonials are numerous. I hope you will join us and recommend this tour to your friends and acquaintances. As a judge with much experience in Schutzhund training and competition, and being very familiar with Western Europe, I am able to give the best tour possible. People going it on their own cannot see the important parts of the country (sometimes we tour adjacent countries, too), and paying for your rental car is more than chipping in to pay for the van and my expenses. Read my "Impressions" on various websites for an idea of what we've seen in recent years.

There will be 3 long days of the big show, and about 3 to 4 days of sightseeing and visits. Please let me know as soon as you can, with a $400 (US) deposit, so I can start putting my notification list together and finalize (hold) hotel reservations for you. There is a lot of work involved in putting together such a tour! I will make the hotel plans based on your deposits, & arrange the visits and van(s). Easy, fun, educational and, for most --- the unique trip of a lifetime. You will not be any younger next year, and if you don't make the decision to get out there and smell the roses NOW, while you think of it, you're more likely than not to lose the opportunity and desire.  Join the group! Tell others about it, too. Fred 

Contact me at  Mr.GSD[at]netscape.com and tell your friends and Internet contacts.
Postal mail: 3565 Parches Cove, Union Grove, AL  35175-8422 USA

Editor’s Note:  A well-respected and frequent GSD specialty and all-breed judge for many clubs around the world, with KC and other-country credentials, Mr. Lanting since 1966 has lectured on Gait-and-Structure, Canine Orthopedic Disorders, and other topics, and has judged in about 30 countries, including the prestigious FCI Asian Shows hosted by Japan Kennel Club and the KC of India, the Scottish Kennel Club, and many National Specialties in the USA and elsewhere. He has been described by a former OFA director as the world’s leading non-veterinarian authority on hip dysplasia. A dog breeder since 1945, a GSD owner since 1947, and a show judge since 1979, he has lectured at numerous veterinary schools in the USA and abroad. He is the author of “must read” books for the dog owner (see below for ordering info).  Curriculum Vitae available upon request.

Announcing the new “Canine HD and Other Orthopedics Disorders” book: The expanded revision is a comprehensive (nearly 600-page), amply illustrated, annotated, monumental work that is suitable as a coffee-table book, a reference work for breeders and veterinarians, and a study adjunct for veterinary students. It is equally valuable for the owner of any breed. It covers every aspect of HD and other orthopedic, bone, or spinal disorders, and includes genetics, diagnostic methods, treatment options, and the role of environment. Your autographed copy will be mailed from the USA as soon as the appropriate amount is received and is processed. Pricing: US $68, plus $5 postage in the U.S., or ask about mail overseas. Combine orders with “The Total German Shepherd Dog” by the same author ($50 plus postage). 17 of the 20 chapters are suitable for owners of any breed.