Fascinating Article on Genetics - Your Thoughts? - Page 2

Kalibeck, it wouldn't surprise me, and DNA testing has proved it in some cases. I know of a case in Australia where a breeder introduced wild dingo blood to his dogs (Aussie Shepherds, I think). He kept the progeny hidden until enough generations had passed that they looked like purebred dogs again, but he was eventually found out, and all his dogs removed from the stud book. Someone else mentioned how Morgan horses had changed in recent years, through the secret introduction of other blood (hackney horse or pony, I think). And no, he is not talking about abandoning breed type, just increasing genetic diversity. The American Rare Breed Assoc. has these rules re. outcrosses: If a breeder out-crosses to another breed to increase genetic diversity and prevent inbreeding, they must allow 3 generations of purebred breeding to pass before the descendants can be shown as representatives of their breed once again. Read the whole article, he describes how it should work. There will be breed standards still, but they will be a little more fluid, and not so much written in stone. He says he found himslelf worried about producing a husky with a floppy ear. He focused so much on purifying his lines that instead he was getting bitches that couldn't whelp normally, and unhealthy dogs plagued with problems as a result of too much inbreeding. Better the odd floppy-eared pup sold as a pet, rather than that!

Gshprdsrul, I've seen that show on before too, it's pretty cool. I believe that show is called "Dog Genius" on National Geographic. They show repeats a lot on that channel, so it should be on again in a few days maybe. ~Lauren

I printed and read the entire article. Good read. I was expecting another - "why all dogs need to be mutts" and it was not at all that way. I think he would argue that mixing lines within a breed would not solve the genetic problems because there is not typically enough "foundation" stock on which to build so he is a proponent of outcrossing with other breeds of similar type and function. Now, the thing that is different about him is that he still believes in breeds and types. Perhaps a loosening of cosmetic standards but NOT working abilty or functional conformation, control by breed club (owning a purebred dog would not confer the right to register its offspring without the dog going through a grading system, not a dog show competition He would do away with pretty dog shows. It is actually, I imagine, with the exception of opening the studbook similar to the level of control enjoyed by the SV. I have to think - you know terriermen and people working hunting dogs do this all the time. WHere I live the police use bloodhound-coonhound crosses for trailing. My first response was with too much outcrossing you would have so many dogs that should be culled and we don't "cull" puppies like perhaps people once did. But he brings up that so many inbred dogs are already defective anyway that we would be producing fewer not more with these outcrosses. _______________________________ Now, question - I hear speculation some of the Czech lines were not actually completely "pure" but many people really like them and I have been really impressed myself. I know the wolf discussion is sketchy, but what about infusion of other breeds? is there knowledge of whether or not they did outcrossing with other breeds?

With the Czech lines, does it really matter? If the dog fits the standard, it fits the standard, and "pure blood" alone can't top that. For when purebreds cease to represent the standard, but are bred anyway, is that German Shepherd breeding? Like the showline/workingline split, we might as well have a pedigreed/meets-standard split! I would say, the SV has "kennel blindness" on a higher level. The genetic diversity in Germany's breeding under the SV system has increasingly narrowed by their own un-doing. The inevitable might be delayed by allowing the infusion of FCI pedigreed dogs to breed into its registry.

Daryl, I think the author of the article is all about the dog fitting the standard, which is a breath of fresh air from the "all dogs should be mutts" school and feels that the infusion of fresh blood is the only way to keep a population healthy. I think he thinks the standard should be related to workability as its primary goal. He also would do away with achondroplastic dwarf breeds, breeds with stupid heads. He also explains how wild animals maintain type AND heterozygocity and one wild animal that suffers from homozygocity (the cheetah) Some quotes: --Canine breeds can and should be differentiated, bred and maintained on a dynamically balanced, heterozygous population basis without restriction to a closed, historic founder group. The closed studbook and the breed purity concept are, from a genetic point of view, simply unnecessary. Indeed, as we have seen, from the standpoint of maintaining a genetically healthy limited population, they are thoroughly counterproductive" --The end in view is healthy stock, not "racial purity." Purged and purified bloodlines would be weak for other reasons, as has been explained. As the mapping of the canine genome progresses and RFLP, allozyme or microsatellite "markers" for common genetic defects are found, we shall probably then be able to use DNA studies to recommend matings that will avoid the production of defective homozygote progeny -- provided that we have made enough genetic diversity available through outcrossing to give us the genetically distinct lines from which to choose! As things stand now, most breeds are so homozygous that it could prove extremely difficult to find matings which would avoid one genetic defect without reinforcing another! The article is old (1996) so obviously it has not taken the dog world by storm. It struck me as very similar to a book I read in the 70's called "The Green Revolution" [which I cannot find now] that argued the commercialization of crop seeds reduced biodiversity, produced homozygous populations unable to adapt to local conditions in other locals and forced the use of pesticides, and fertilizers as the new high producing strains could not produce without them. With our approach to now start cloning animals it takes us even closer to standardization and reduction of genetic variablity.

Please recognize that I am not a critic of linebreeding. I think appropriate use of outcrossing AND linebreeding is essential to good breeding. Both practices can be done while achieving heterozygosity, and maintaining genetic diversity in the overall population. Too much practice of either, can create it's own set of problems.

Daryl the article on your web page is the most concise and undertandable thing I have read on linebreeding and outcrossing and the balance between the two. I am not sure he even advocates completely doing away with linebreeding but argues that the studbook closes very early in the development of most breeds so there is not enough foundation stock to ensure heterozygosity. I guess the question this article poses is: Is there currently enough genetic diversity within the breed = "German Shepherd" to ensure heterozygosity?

I think theres enough to last a couple hundred years, if we "budget our resources" well, fifty years if we don't. It depends on a lot, like how much senseless outcrossing and counterproductive linebreeding, or what system of politics is governing the breeding practices, how well breeders work together, how unified the "vision of the breed" becomes. The Roman Empire didn't fall in a day, it was a "slow crumble". The salvation or destruction of the breed may be realized even well before fifty years and by my estimate, some field of "bio-molecular genetic engineering" will revolutionize the way we percieve any species, and give us the power to transform it. With the recent completion of sequenceing the canine genome, and the cloning technology, it's only a brief matter of time. This article relates how particular sections of DNA are being manipulated already. "We developed a method for deleting any piece of DNA from the mouse genetic blueprint very efficiently." http://unews.utah.edu/p/?r=060107-2 If this technology becomes easily available, we won't have to "fix the breeders" in order to fix the breed.