GENETICS AND THE MYTH

I’ve read and studied. I’ve experimented and read some more. I have come to the conclusion that there are no guarantees when you are breeding dogs. What ever is said about genetics has to be said with the word “maybe” in the sentence. There are many “experts” out there and it is easy to observe that most of them disagree about more then one point.

Well, I’m no expert or even near to one. But I have observed and been active in German Shepherds for thirty years and I have heard phrases that state - outcross breeding is safe. Outcross breeding produces healthy puppies. Outcross breeding will disperse the “problem” and soon it will go away. Hmmmm ! I doubt it.

Let me explain how the in-breeding can help improve your line with an imaginary dog. Sue is a White German Shepherd that has won in the breed ring, and has wonderful temperament, and comes from an outstanding line. She is an outcross without any same ancestors in her pedigree. You want to breed her, but find out she is mildly dysplastic. Should you or shouldn’t you? While you are pondering this dilemma, you hear that Mrs. Jones has a male White German Shepherd, I’ll call him Joe, that is the product of an Opps litter, a mother and son mating.. And while talking with Mrs. Jones, you find out all her dogs have been OFA excellent for several generations and this young male is OFA. Now the odds are in your favor, if you use this male with your girl. He is very probably pre-potent. Said simply, his genes are stronger then hers, and MAYBE the pups will inherit his sound hips. A large percentage of the pups should have good hips, maybe 75%. If you do an outcross mating, with an OFA male, you will have a chance of half the pups will have a good outcome.

Joe’s genes are pre potent because of the in-breeding. Prepotency is the ability of the dog to produce offspring that are like himself. It produces a whole litter that are very similar in shape and size. If you think about it for a moment, Joe received 50 % of his genes from his mother and 50% from his father, but his father had 50% of his genes from Joe’s mother. So Joe has 75% of his genes from his mother. The chances of his pups inheriting mothers genes are pretty good.

Of course there is the chance of other inherited diseases. But if you have spent enough time with the breeder of the inbred male and discussed what problems she has had in her lines and know the outcome of other pups in the same litter with the male, you should have a good idea what to expect. .And if you start with sound, healthy dogs there shouldn’t be a problem. And if there is a problem, then you know what you have to breed for, no more guessing games. That outcross male has inherited genes that could pose a problem that you will not know about till the pups are here or even longer. Those genes could remain hidden for several generations. You know that every dog, on an average, has 7 genetic faults.

When I hear about the good old dogs and how sound they were, and so beautiful and healthy, I always smile. Inside I am chuckling. Max von Stephenitz, the founder of the German Shepherd breed, used in-breeding, and occasionally line-breeding and out-crosses. Here is a quote from his book. “Inbreeding secures for a valuable strain the highest influences on the breed; it strengthens the development and the inheritability of characteristics, and, in consequence, makes the introduction and the consolidation of new characteristics possible, and increases the dominance of the strain, as compared with others.” Another quote “ The best results are, however, according to Graf Lehndorff, obtained by inbreeding in the 4^th generation on a common ancestor that is to say, a great-great-grandfather.”

Lloyd C Bracket, a long time German Shepherd breeder , produced 90 champions in 12 years using in-breeding and line-breeding. His Longworth Kennels is famous and his dogs dominated the show scene in the 1960’s. He started with three brothers and a daughter from each male. They all went back to Utz. He explained that the bitch’s background is of utmost importance. And he states, “ year after year, and generation after generation, this foundation blood continued to intensify in the pedigrees of my dogs. MODIFIED outcrossings were made only occasionally. By modified, I mean that, when reaching out for some needed trait, I used a stud or bitch possessing at least one-fourth, or better, one-half, of the blood of my strain”.

It was interesting to read that Mr. Bracket thought there was danger in continued outcrossing. If you remember, when the Mendel pea was crossed, the results were a very vigorous, healthy plant. That was called hybrid vigor. But when the next generation was crossed, the results were back to square one with 50% mixed, 25% short and 25% tall plants . It was a disaster. This has happened on the farm with poultry and livestock. First crosses are uniform and satisfactory, but if the hybrids are bred again, the results are disappointing.

Another problem with outcrossing is that it hides the recessive genes. Some of them might be very harmful. They are still there, being passed to the offspring, unknown to the breeders, but still there and can become very widespread before it is discovered. A person has a very good chance of finding out what problems are “underneath” when they in-breed. It is better to know, and then plan the breedings with that knowledge. If a person breeds without any understanding about Mendelian genetics, Galton’s Law of Inheritance, in-breeding, line-breeding, outcross, estimated breeding values, etc.- they are not planning on improving the breed. At least I would have some grave doubts.

Mendelism is inheritance by pairs of genes. Each pair is made up of one part from the stud and one from the dam. Each gene maintains its identy and when a dog reproduces, it transmits to each pup only one half of its gene. If Aa represents a pair of genes in each parent, A being dominant and a being recessive, the pup has one chance in four that the pup will get AA, one chance in four that the pup will get aa, and there are two chances in four that the pup will receive Aa. The A dominate gene is the one that expresses itself over the recessive. The recessive could go partly or completely concealed for a long time. This is the problem, because genetic birth defects are caused by recessive genes. This is simple enough , but not the whole story , many birth defects are the result of multiple genes. It becomes an educated guessing game among the experts, and they give us many different theories to ponder. Everyone wants to avoid genetic defects. Many birth defects are from environmental factors, but others are the result of bad or lethal genes. It would be best for the breed if none of these bad genes were passed on to the pups.

Many lethal defects are thought to be double recessives found at a single location on the DNA map. Another theory holds that lethals are polygenic and that a larger number of genes combine to influence or create the defect. This could mean that a pup could inherit 95% of the lethal genes from one parent and 5% from the other. With the emergence of DNA testing, we might have some answers or part answers to help us discover the complete solution.

A sure fire way to identify bad genes and eliminate lethal recessives is to test mate. Breed the father to the daughter or the mother to the son. The incidence of even one defect is a strong indication that the bad gene is there. This approach tests for all lethal genes at the same time. When you outcross, the bad gene does not show up until it is spread throughout the whole population, and the problem is much harder to bring under control.

Galton’s Law states that a dog is half its sire and half its dam. Then that sire and dam are each half their sire and dam, and it follows for each generation. So the chance of getting a genetic contribution from various parents or grandparents can be figured mathematically. So each parent is one half and each grandparent is one fourth, and each greatgrand parent is one eighth and so it can be figured as far back as you wish to go. Galton’s law is worth thinking about. It can show you how much influence any certain dog has on the planned puppy. If a certain stud appears back in the fourth generation, the chances are that his genes are so diluted, that his influence is very little. If the stud appears in the fourth generation on both sides, (4-4) the percent of influence would be 12.5 %. A (3-3) or the same ancestor in the third generation on both sides would be 25% influence. That still isn’t a very strong influence. A (3-2) or same ancestor in the third generation on the studs side and in the second generation on the dams side would be 37.5% influence. This would be line breeding that will have enough influence for the breeder to consider. This type of mathematical outcome also shows that the outcross can be expected to equal the average, not the outstanding specimen..

Breeders select which dogs will become parents. The most common method is based on how the animal looks, phenotypic selection. Selection based solely on how the dogs look is not very reliable. This would include breeding to a champion without any other consideration. Most breeders assume that breeding superior animals is just the process of breeding champion to champion. If that were true we could all be successful breeders. The next is analysis of the pedigree. Galton’s law helps with that analysis. The third method is to evaluate the offspring that has been produced by the sire, dam, grandparents, etc. The progeny test helps to determine the genotype. This measures the genetic makeup of an individual, the effect of an individual’s genes on its performance for a trait. Simply stated, do they throw as good as they are, better or worse. It would be prudent to use all three methods when planning a litter.

Every breeder should have a breeding plan. The short range one mating plan, and it should be part of the larger overall goal that should include improving the breed. The plan starts with the standard for the breed. If you can’t read and understand the standard, you should start there. How can you justify you are improving the breed if you do not know what the experts, the breeders of the past thought were the goals to aspire to? How will you know if you are breeding a short stifle or a steep croup? How will you know what is important, and how will you know what any other breeder is talking about if you don’t understand what the standard says. If you disagree with the standard, you better have some pretty good reasons other then “I like this, so I don’t care what the experts say”.(that is what puppy mills say) The next step is you start with healthy animals. You are not improving the breed if you start with genetic faults that you know about and do not breed to eliminate. The breeding plan does not stop at the first mating, but you should have the next several matings mapped out to follow up on what you are trying to improve. Everytime you go to a dog show you are evaluating and classifying the dogs on who will improve what you have. Will they fit into your long range plan. You go home and study their pedigree and talk to others to see what they have produced. It is a continual learning process as long as you are breeding dogs.

Everyone who is breeding dogs should have in their possession several genetic books, and be a student of the many theories that are expressed in these books. There are many fine articles on the web and often there are seminars on the subject. There are classes offered in colleges and on the web. There is so much information available, that there should be a means of learning for everyones situation. I have a pedigree program on my computer and although it is old now, it figures out the co-efficients and percentages for me and that is worth lots. The explanations and directions are in the books, and you can figure it all out long hand, if you don’t have a pedigree program, but if you can afford it, the computer program is well worth the investment.

It is important to understand that outbreeding does not eliminate bad genes. It actually perpetuates them by masking their expression, making selection against them ineffective. It spreads the bad genes throughout the population. Outbreeding can be effectively used to promote hybrid vigor, improve fertility and size. It is not effective when used for every litter.

In-breeding increases the uniformity of positive traits. In-breeding can be used to eliminate unwanted alleles for certain traits or bad genes. In-breeding produces prepotency or the ability to produce offspring like themselves.

Myrna Giles, German Shepherd owner for 30 years.