wondering................

[science_doc]

I read an article about dog breeding in a science magazine and I was wondering about the opinion of people who actually breed dogs. Okay, we can all agree that inbreeding is bad an causes genetic disease. So that being said, many dog breeds are seriously inbred and frought with genetic problems, right? So the suggestions made by scientist (just a general example we can talk about specifics later if your interested) would be to cross a breed like GSD with a similar dog (this was not totally clear, perhaps another similar type of shepherd), this would introduce new genetic combinations into the line, then breed those dogs back to a "pure" breed. You would then be able to select puppies/adults with the traits expected for the GSD. I was wondering if there is ANY interest in "fixing" the current breeding lines or have people become too set in their ways of pure bred to pure bred to even consider these options. This stuff makes sense to me, but then I am a geeky scientist.

[Poofy]

you said:
"I read an article about dog breeding in a science magazine and I was wondering about the opinion of people who actually breed dogs. Okay, we can all agree that inbreeding is bad an causes genetic disease."


Inbreeding does not cause genetic disease. Please, please, please do some reading about genetics.


You said:

"So that being said, many dog breeds are seriously inbred and frought with genetic problems, right? So the suggestions made by scientist (just a general example we can talk about specifics later if your interested) would be to cross a breed like GSD with a similar dog (this was not totally clear, perhaps another similar type of shepherd), this would introduce new genetic combinations into the line, then breed those dogs back to a "pure" breed. You would then be able to select puppies/adults with the traits expected for the GSD. "


Hmmmm...I am really beginning to wonder about the "scientist" who wrote this article.
What this person is reffering to is hybrid vigor. Yes, you can increase heterozygosty through a hybrid breeding, however that vigor is only good for the F1 generation. It does not preceed it and once you take that hybrid back into the line, what ever problems were there, will be there again. Also, what are you going to do when there are genetic disease that are across species? Hip dysplasia effectc ALL breeds, no matter how big or small...you cannot avoid it by hybrid vigor. To many genes and modifiers play a part in the problem. Infact, through a "hybrid" you can actually introduce problems that were never there.
The key is to BREED SMART....select healthy animals to begin with and use the tools we have today to select for supior animals.


You said"You would then be able to select puppies/adults with the traits expected for the GSD. I was wondering if there is ANY interest in "fixing" the current breeding lines or have people become too set in their ways of pure bred to pure bred to even consider these options. This stuff makes sense to me, but then I am a geeky scientist."


Firstly, you cannot "fix" the problems by these methods. And quite honestly, well bred dogs (perhaps some of the most in bred ones) do not have the majority of problems that are listed as breed specific, because breeders *screen* for those diseases before breeding. When diseases are based on a simple autosonomal recessive or domiant trait, it can be quickly eleminated...those influenced by modifiers and or poly genes, can take longer but can still be changed over time....through selective breeding.
And once you make the line "pure again" the problems you have will be there all over again....the ONLY way you will get rid of the problem is to not breed them...and breeding hybrids has nothing to do with that.

[imported_Cassie]

Science_doc, A book you would find very interesting is called "Dogs, A startling new understanding of Canine Origin, Behavior & Evolution" written by Raymond Coppinger and Lorna Coppinger...they basically have the same theory in which they beleive this modern emphasis on breeding has trapped our breeds in genetic isolation, and they state they would like to see our purebred dogs escape from these restraints.

Alot of my Freinds breed dogs so I would'nt dare discuss this view with them...they are very closed minded about such things...I like to keep an open mind about such things, and have started reading the above book and I have learned some pretty interesting things about natural selection of dogs verses artificial selection and so on...get the book, your scientific mind will really enjoy it. I always thought mother nature was much better at the breeding game than when we humans interfer...

[Hobbit]

Science Doc --- I think the article may be referring to something else. If a person wanted to incorporate a certain trait into a breed of dog that they had, they could manipulate a trait in using the genetics from another dog. Example: a while ago (like 8 to 9 years ago) some very political people decided that they wanted their Aussies to be able to hunt. So, thru the graces of the AKC, they were allowed to bred their Aussie to a Brittany -- "to put a better nose on them". That crossed puppy was then bred back to an Aussie (when old enough) and allowed to be registered as an Aussie. Jacsmom had some information on some other breeds being allowed to incorporate *outside* genes into a breed and then breed back for registration status. It was posted a while back on this forum.

Several breeders do this to achieve the "perfect" herding dog, hunting dog, protection dog, etc... An understanding, a GOOD understanding, of genetics is needed. Both dogs need to be tested for genetic defects before breeding, or the offspring will be carriers or affected.

Another example would be: If a person that raised Border Collies wanted more bite (and didn't want to take the time to breed selectively from BC's that had bite), then they could breed with another breed that was more animal aggressive, then breed back to a BC. It's being done alot in Oklahoma. People that are avid herd triallers are breeding a good working BC to a Kelpie, then crossing that offspring with an APBT. Some are breeding the BC to an APBT, then crossing that offspring to a Kelpie, then crossing back onto a BC.

The use of similar breeds, will mostly ensure that the "look" of the original breed isn't deviated too much (from standard).

Unsoundness bred to unsoundness will produce unsoundness any way you go about it.

[science_doc]

Poofy,
[b]Inbreeding does cause genetic disease[/b], I am a medical researcher and have taken MANY graduate level genetics classes. I realize that sceening will help prevent a disease [b]phenotype [/b] from appearing in some dogs. However, there is a genetic phenomenon call "bottle necking" when a population becomes unable to breed outside it's group, genetic mutations become trapped within the population. There are no new alleic combinations available to the population so muations in essence become "trapped" in that population. For example, if your mom and dad are related, there is a much higher frequencey that they will carry the same mutations, then there is a great chance that you will receive 2 bad copies a a certain allele. This is why endangered tigers are being crossed with lions in zoos. In order to maintain what you called "hybrid vigor" you would need to breed the F1 generations together, then begin selecting from those animals to breed a particular trait in the F2 and beyond. We do these breeding things in mice all the time, so I have some understanding and experience with mice, I'm just not as well versed in canine genetics. WE ALL HAVE MUTATIONS EVERYDAY and when you breed with only those related to you, you will have malformed off spring, I'm sorry you don't like that, but those are the facts of life. "Healthy" animals can and do harbor mutations that when crossed to a dog of a similar genetic makeup will definately present a problem for their offspring.

Hobbit,
I am pretty new to the idea of dog genetics, but I think that it's very cool. I have no interest in breeding dogs myself, but being a dog lover, I am wondering about the long term consequences of age old breeding practices. I have read that some breeds are almost entirely decended from a few champion lines, is this true? I would be really interested in learning more about how champion dogs are bred.

Cassie,
Thanks for the book title....I'm going to try and find it this week!

[Pennynewf]

you might want to pick a breed you are interested in, and than go study the different lines, and the different things those lines focus on.
for instance, in newfoundlands there is one kennel in particular that only breeds for performance and working and stays away from conformation, i try to do both, but try to stay away from the lines known to change with the latest fads, i also have studied years the different lines in our breed and certain ones are tried and true.
what you say does make sense to an extent, good luck science doc.

[bullygirl29532]

just my 2cents but about human inbreeding 60% of world cultures it is not uncommon to marry your 1st cousin and a child of such a union only has a .008% chance of being abnormal compared to "normal" children. genetics like all sience and medical fields is a practise. I believe whether it be human or canine it all boils down to SELECTIVE breeding.

[science_doc]

Again, inbreeding all boils down to a game of statistics.....if you look at the children of a single first cousin marriage, there might not be much of a problem (unless their family has a previous history of in breeding), but would you ask the brother and sister of a 1st cousin marriage to get together and have some children? The fewer the members of a population that are breeding the greater the likelyhood that mutations that arise spontaneously will cause problems in the population rather than be diluted through a large genetic pool. These are the basics of nature and natural selection, I know that breeders believe in selection of genetic traits through breeding, what I don't understand is how they fail to realize that bad traits will segregate with good traits too.

[Hobbit]

[quote name='science_doc'] what I don't understand is how they fail to realize that bad traits will segregate with good traits too.[/quote]


Because they don't understand genetics or they don't care. They are after one specific trait or "LOOK". Some listen to what someone else says about breeding brother to sister ---- without understanding the possible outcome. The person telling them it is okay to continue to breed brother and sister --- usually has NEVER even heard the word genetic, let alone knows anything about it.

[science_doc]

Since I am surrounded by scientist everyday, I often forget what life is like in the real world outside the lab :oops: I just wish that people would be more careful and considerate about things they don't understand. I worry about the future of pure bred dogs.......but I guess there are plenty of other things to worry about in the canine world.

[Hobbit]

[quote name='science_doc']
Hobbit,
I am pretty new to the idea of dog genetics, but I think that it's very cool. I have no interest in breeding dogs myself, but being a dog lover, I am wondering about the long term consequences of age old breeding practices. I have read that some breeds are almost entirely decended from a few champion lines, is this true? I would be really interested in learning more about how champion dogs are bred.

[/quote]


I can only comment on the breeds that I deal with; ACD's, Border Collie, Aussie, and Kelpie.

If the current breeding practices and attitudes toward breeding do not change, the ACD as a breed will surely not survive.

AKC show breeders are breeding for *looks* only, caring nothing about health. Caring only that they win in the show ring. This is evident by their breeding practices, attitudes and reluctance to change. Currently, a large portion of all ACD's are carrier's or affected for PRA. Breeders are not wanting to STOP breeding these carrier's or affected ones because as several breeders have said, "He's/she's a champion and I want a litter from him/her because of it", AND, "Well, he/she will probably go blind at around 9 or 10, but by then his/her show career will be over --- so who cares". They continue to do intensive inbreeding, fully knowing that their breeding stock has a genetic defect. They continue to breed without ANY regard to the consequences of the offspring, dog, or breed.

Their excuse for their continual breeding of genetic defected dogs is that if they didn't, "the gene pool would be limited". Ask them what they mean by this? They haven't a clue. They don't want to stop because ALL they care about is WINNING. They dont' care about the breed, the dog or any consequences whatsoever!


The Border Collie is becoming a show dog that is plagued with seizures, CEA and hip displaysia. As long as a particular dog is winning in the show ring, he/she will continue to be used for breeding ---- REGARDLESS of their health or genetic defects.

[Hobbit]

[quote name='MiniAussies']Here we go again with the ole Genetics stuff. :roll:[/quote]


I've been patient with you so far. Genetics IS the foundation of what is what, what is created, how it is created, and why. YOU don't have a clue, do you? It's obvious by this post and your previous post concerning the *Mini-Aussies.

Would you like to contribute any of your genetics knowledge to this thread? Please do so, I would really like to hear your views --- genetically speaking, of course.

[Pennynewf]

carriers of cystinuria can be bred to normal, and eventually we can breed it out, affecteds never should be bred, i am not sure this works the same for the post about acd dogs and pra disease

[Poofy]

you said:

"Inbreeding does cause genetic disease, I am a medical researcher and have taken MANY graduate level genetics classes. I realize that sceening will help prevent a disease phenotype from appearing in some dogs. However, there is a genetic phenomenon call "bottle necking" when a population becomes unable to breed outside it's group, genetic mutations become trapped within the population. "


I am sorry but you are wrong. In breeding does not *cause* genetic disease. Genetics 101 will teach you that. Inbreeding may increase the possibility of particular alleles comming into combination. Those combinations of alleles may cause a genetic disease. Those "bad" alleles, which are the result of mutations on a molecular level, usually over multiple generations, may cause a deficiantcy which in turn may allow for the developement of a genetic anomolie. Inbreeding only increases the chances for the combination that *already exsists* it doe not "create" or "cause" the problem. Those molecular changes can also be beneificial allowing for certian alleles to come into combination and eventually meet and there for give the next generation the edge it needs for survival. Detrimental "problems" are often lost when they crop up do to the organisms ability for survival.
Screening for genetic dieases does more then just reveal the phenotypic type of the animal. It also tells the breeder that the animals either carries enough modifiers or not enough alleles in order for it to develope the disease. While it cannot tell you wether or not it is a carrier, it gives you a heads up.
Genetic bottle necks:
While a genetic bottle neck is a concern when dealing with *wild* populations it is not that big of a concern when dealing with domestic. Mainly because domestic animals do not need the ability to of adaptation to their invironment for survival. To some exstent yes, such as immune syste, etc. But over all, we control their food, their shelter etc. In a wild population, especially one that is realatively isolated, loss of the gene pool has more of an impact. As we are back to those molecular mutations that build up over time and allow for the animals to adapt to change. Also, thanks to crossover and mutation, there will always be diversity to some degree unless you are so deliberate as to inter breed multiple father daughter, mother son generations, inorder to achieve a COI of 100%. Even in that event, in some species, particularly rats, it can go one for 50 or more generations with no side effects. Eventually you will reduce your immune system as well as your fertility. However, all species only have so long before they are exsitinct any how. In wild populations exsistance may only be a brief 10 thousand years...sometimes less. Logistically, in the time that it would take breeders to "kill off" the canine species, the human species will most likely be gone any how.
Any how, inbreeding does not cause genetic disease...it cannot cause genetic disease....it only brings together those unwanted alleles which can then be erradicated from the gene pool making it stronger. You will not find and or track problems by "avoiding" them. You are better off to eliminate the true source.

I will leave you with this from Geneticist Malcolm Willis " It is well established that inbreeding tends to be associated with the appearance of defects. This is a true observation but breeders must not imagine that inbreeding creates such defects..."

[Poofy]

Human Inbreeding:


We wonderful angelosaxon people tend to become a bit ethno eccentric and forget that there are other cultures out there. Many, many, many african and or non-industialized brazilan cultures (like the Yamo-Mamo) do not view family "relation" as we do. It is common for some to only veiw kinship through either the paternal or maternal side. Thus, making half brother half sister combinations a very common occurance. These countries have no problem procreating gneration after generation, which is the source of their problems dealing with famine.
Also, you must remember that every species is different. What is considered inbreeding, on genetic level for one, may not be for another. Again, rats, which are able to inbreed to extremely high levels of COI but face no ill effects (as long as the inbreeding occures in nature and not in a labratory environment where unnatural selection occures). There is a herd of cattle documented in England, that has been fenced off and contained for the last 50 some odd years, where they have been allowed to breed to a level of nearly 100% COI with no ill effects. This goes for some breeds of dogs as well. A COI of 30% in one breed is much more devistating then in another. Considering even the most inbred lines rarely achieve over 18%, inbreeding is not reason for poor specimines. The reason there are poor specimines is because there are poor breeders and those who deliberately continue weak and debilitated lines.
Finally COI, or the "math" involved with calculating inbreeding cannot account for the two sources that continue to maintain genetic diversity, cross over and mutation (on the molecular level) which occures evertime a germ cell goes through meiosis.

[science_doc]

Poofy you are talking about semantics...........you are absolutely right that inbreeding does not CAUSE disease in the direct sense of the word. The exact same thing can be said about smoking. Smoking itself is not going to kill you outright, however it will greatly increase the mutational rate within lung, throat, and mouth tissue which will greatly increase the likelyhood of developing cancer. A mutation does not need several generations to cause a problem. A mutation in DNA often causes an errant protein which can have an immediate effect within the organism or in their off spring. Just ask someone with muscular dystrophy how long their single mutation took to change their life. You are using words like "molecular" and "anomolie" to make it appear like you have deep scientific understanding of genetics, which it is clear that you do not. When the frequency of a recessive mutation within a population is 0.01% a first cousin mating has a 7 fold chance of producing a homozygous recessive offspring. Basically if the mutation is there inbreeding will bring it out for sure (Primer of Population Genetic, Daniel Hartl).

You are using semantics to continue breeding in a manner which is hurting and will continue to hurt dog breeds far into the next century. They are not outbreeding tigers with lions because they are "wild" creatures, but rather because this is the ONLY way to eliminate the "molecular" mutations you mentioned. A genetic bottle neck hurts a wild population for the reasons you mentioned, but the same bottle neck could give rise to many canine diseases that appear to me to be endemic within a majority of the population. I don't think that you fully understand the meaning of "crossing over". This type of mutation, and it is often a HARMFUL mutation (resulting in losses of big chunks of chromosome due to incomplete segregation), while it can create new allelic combinations cannot introduce new alleles into the population and would not serve to disrupt the problems associated with inbreeding. I would love to see your peer reviewed scietific references on how inbreeding is not harmful to wild rodent populations or cow herds. Don't domestic livestock farmers pay thousands of dollars to bring in the stud from the next county instead of their own heard?

Continue breeding dogs from the same lines to the same lines and you are going to produce deeply inbred strains with some very common genetic problems. The ONLY way to eliminate those alleles from the population is by outbreeding, mutations don't really fix themselves very often. Sure you can pick up some problems with genetic screening and I have no idea how good the screens are for canines, but for humans they can't detect too many disease by screening yet and we have the entire human genome at our finger tips.

Your answer is sort of what I was afraid I would find within the dog breeding community, otherwise this wouldn't be the problem that it is today. One more question before I give up this discussion as an agreement to disagree: How many truly outbred (real heinz 57 mutt, not the product of an accidental purebred + sneeky neighboors dog) dogs suffer from hip dysplasia, early on set blindness, or seizures (just to name a few of the disease I have heard of)? I just don't understand how things like hip dysplasia can be nearly endemic in almost all the large breeds, but still thought of as independent of inbreeding and genetics.

As far as human inbreeding, why the heck are all the super inbred royal families of Europe the first thing studied in population genetics? All their gorgeous family trees with the beautiful disease founders passing their problems from generation to generation to generation............

[Pennynewf]

Well now i must say this, i have seen just as many mixed heinz 57 with luxating patellas and hip displaycia, and eye problems and awful bites and allergies and other problems just as much as purebreds, i am sorry but that just does not sit well with me, i have seen some with eye disease that is awful or cocker mixes with horrid ear problems, i am a groomer of 15 years, boarding dogs also and worked at vet clinics to see many variety of canine, you just cannot say that to me and have me agree with you that the heinz 57 is healthier, how many people have hips that are bad or knees that are bad or feet becouse of the JOB they do, environment plays a huge role as well diet in CHD

[Pennynewf]

One more thing, mixed breeds dont ofa or penn hip, nor do they much care to test for anything, that is why you never hear of them having problems, becouse they just throw two and two together or the accidant will make a nice pet for someone.
i on the otherhand require at least a prelim at a young age before the growth stages so that we can guide our puppy people on the proper care, diet etc... that goes into owning a giant breed pup.

[Hobbit]

It STILL all connects back to genetics. They may be predisposed for a genetic defect and the environment pulled (or has pulled) the trigger.

[Pennynewf]

Show me the marker for CHD, and prove it is strictly genetic.
yes it may be, or it may not be.

[Hobbit]

[quote name='Pennynewf']Show me the marker for CHD, and prove it is strictly genetic.
yes it may be, or it may not be.[/quote]


Other factors can come into the picture sometimes -- like nutrition and environment (thus...environment pulling the trigger). [b]CHD is however; an inherited disease. [/b] A dog may be predisposed, genetically, for CHD and when exposed to additional supplementation and overnutrition that is not needed --- the CHD occurs. IF the dog had been fed properly, housed properly, exercised properly --- the CHD may not have shown up until later or been less severe, there is no way to tell this. It's not something that you can predict, you can only manage it (if the dog comes from CHD parents).

"Canine hip dysplasia (CHD) is the most frequently encountered orthopedic disease in veterinary medicine practice. This extremely common heritable disorder of the growing dog can be influenced by nutrition. The period from 3 to 8 months of age appears to be important in the development of CHD, with the first 6 months generally thought to be the most critical. Early developmental findings of CHD, including joint laxity and coxofemoral anatomic changes, have been documented within 2 weeks of birth. Rapid weight gain in German shepherds during the first 60 days after birth has been associated with CHD at a later age. Frequency and severity of CHD are influenced by weight gain in growing dogs, especially if sired by parents with CHD or with a high incidence of CHD in their offspring. Dogs with weight gains exceeding breed standards have a higher frequency of CHD as well as more severe CHD than dogs with weight gain below the standard curve. In one colony of fast growing Labrador retrievers, the triradiate growth plates of the acetabula fused at 5 months as determined by conventional radiography; normal closure of these growth plates in pups growing at conventional rates has been reported to occur at 6 months. Early fusion in the acetabulum is speculated to result in bone/cartilage disparities in the future and to predispose to dysplastic changes. Limiting food intake in growing Labrador retriever puppies has been associated with less subluxation of the femoral head and fewer signs of hip dysplasia". Daniel C. Richardson DVM Diplomate, American College of Veterinary Surgeons

[science_doc]

The lack of genetic markers for canine diseases is exactly my point. Breeders claim they are only breeding "healthy" animals, but if there are no genetic screens, there is no way to know for sure. You can wait for a certain age to demonstrate that one specific animal doesn't have a disease phenotypically, but there is no way to know that they are not a carrier of a disease genotypically.

In case you all are wondering what put the bee in my bonnet about dog genetics, here is a link to the article I read:

[url]http://www.discover.com/apr_03/featscienceof.html[/url]

Okay, Discover is not a peer reviewed scientific journal, but even a simpleton like me can understand the physics articles, LOL.

I also found this site on a quick web search, but buyer beware, I haven't finished reading the whole site. I just think the first paragraph seems pretty interesting:

[url]http://www.magmacom.com/~kaitlin/diverse.html[/url]

I just wanted to say that I never ment to offend anyone with these posts.....I felt like this was a chance to combine my job which I have a great deal of knowledge about with my hobbie, where I often feel like a "little dog" amongst the "big dogs". So I guess I do feel emotional about the issue of dog genetics, cause it is so near and dear to my heart.

[Hobbit]

[quote name='science_doc']The lack of genetic markers for canine diseases is exactly my point. Breeders claim they are only breeding "healthy" animals, but if there are no genetic screens, there is no way to know for sure. You can wait for a certain age to demonstrate that one specific animal doesn't have a disease phenotypically, but there is no way to know that they are not a carrier of a disease genotypically.

In case you all are wondering what put the bee in my bonnet about dog genetics, here is a link to the article I read:

[url]http://www.discover.com/apr_03/featscienceof.html[/url]

Okay, Discover is not a peer reviewed scientific journal, but even a simpleton like me can understand the physics articles, LOL.

I also found this site on a quick web search, but buyer beware, I haven't finished reading the whole site. I just think the first paragraph seems pretty interesting:

[url]http://www.magmacom.com/~kaitlin/diverse.html[/url]

I just wanted to say that I never ment to offend anyone with these posts.....I felt like this was a chance to combine my job which I have a great deal of knowledge about with my hobbie, where I often feel like a "little dog" amongst the "big dogs". So I guess I do feel emotional about the issue of dog genetics, cause it is so near and dear to my heart.[/quote]


Thanks for posting the articles. I read the first and will read the second later.

I can see the rational thinking on their part and understand what they are saying. It is ALL about winning for some that show and NOT about the dog. As long as this mind-set is prevalent, then genetic defects will continue to be knowingly passed from generation to generation. There are exceptions, so before anyone gets their dander up --- I did say "exceptions". And those are the very few that actually care about the dog first.....instead of winning.

You did not offend me --- post on!!! :wink:

You are right, no one can know 100% what hidden genetic defects their dogs are carrying.

[Hobbit]

I do have to chuckle about the cow herd. If a person uses the same bull over and over, for many years --- production will.....let me see if I can put this in a term that everyone will understand....SUCK. There will be genetic monstrosities produced, milk production will dimenish (I'm talking milk for offspring), fertility will be affected, mothering ability, calving ease, birth weight, rate of gain....etc... Intense inbreeding/linebreeding of this nature is not something that can continue for many generations. A NEW bull (with new bloodlines) needs to be introduced into the herd. One that comes from producing parents to improve your herd.

Sheep, goats, horses and swine are the same way. Dogs are too. You've probably seen it and just didn't realize it. One dog wins and he becomes the most popular sire in town. If he is a carrier for a genetic defect --- this isn't something that anyone cares about -- Noooo, they only care that he is a champion and they want to breed to him in an effort to produce a champion from their bitch --- not caring about the consequences of the genetic defect on the offspring.

[science_doc]

Thanks K :D For cleaning up the thread.

The science geek inside of me is havaing a total blast!