Genetic Management of Dog Breed Populations - Page 1

A must read for every breeder and dog enthusiast:
http://www.instituteofcaninebiology.org/7/post/2014/02/genetic-management-of-dog-breed-populations.html

looks like interesting reading, but almost impossible to translate to real breeding one on one, furthermore there are some serious theoretical misinterpretations in this story, I was personally visiting several lectures of this autor and there are quite a fewthings that I have problems with in his stories

for example, when he stated that there are growing numbers of problems in several breeds as a result of inbreeding, I ased him for the origin of his information, and his answer was that there are growing numbers of sick animals coming to veterinarian university of Utrecht

when I asked him if these dogs were from linebred or outcros breedings, diferent lines or many problems showing up in one bloodline or offspring of one dog , he had absolutely NO background information on the dogs he was stating his findings on

Fact is that good and bad genes will be passed on regardless if you linebreed or outcross so bigger importance should be given in my opinion to testing and selecting of breeding material, more so than blaming a way of breeding, be it line/in breeding or outcrossing

furthermore I will say what I saidmany time before, if you want to outcross, you need different pure bloodlines available, the only way to maintain that siuation is to line/inbreed  

one other point he makes is of greater importance, if everybody runs to breed the great flavour of the day dog , even when making an outcross on him, the global influence on the genepool is of much bigger influence than when I inbreed my dogs to the max, where the influenco of that on te global genepool of he breed wil be allmost nothing

"When I asked him if these dogs were from linebred or outcross
breedings, or many problems showing up in one bloodline or the
offspring of one dog, he had absolutely NO information on the dogs
he was stating his findings on."


Oh, how true, Duke.  The Kennel Club (UK) has already for some
time taken the same line on "inbred problems" in purebred dogs;
and as far as I have ever been able to find out, most of what the Club
has declared to be the case is based on precisely this level of (non)
information from the Veterinary profession.  They do not provide
exact figures on the increase in cases seen by either clinics or the
vet hospitals,  or make any acknowledgement of other factors like
peer pressure to use vet services, greater education, better commun-
ication of information, activity levels & funding of Animal Protection
organisations,  which can all result in an increase in numbers of pets
taken to the vet./ conditions treated.  Nor can our vet. industry back up
the claims any better than this Dutch person, 'cos when you take your
dog to a vet, they do not ask about its breeding.

Not saying there are no hereditary issues to be improved upon;  or that
everything in the garden is lovely, with every breeder taking the trouble to
try to breed out / avoid the unwanted conditions ... but dog people should
still take what is said about line breeding with a very large pinch of salt, IMO.

you are so right, the english story is the same, for example, they blame healthproblems of english bulldogs to inbreeding while in fact, the selection and desire for extremes is the real problem, if you outcross two dogs with extreme short noses it will not make the breathingproblems go away, on the other hand if you inbreed on dogs with longer noses and make that a solid factor in your inbred line, it will make the breathingproblems go away.

too many people having a title today are absolutely clueless and start to write and scream things , one dutch geneticist is now making a study about how to geneticly reduce agression in chickens that are boxed up by thousands, and avoid kannibalism, while we know that agression/kannibalism will occur  with many species that will be boxed up like that, be it chickens, rodents, reptiles and even people

this geneticist is also giving lectures to dogbreeders against linebreeding

I consider this one of the best articles I've ever come across on dog genetics: http://www.netpets.com/dogs/healthspa/bragg.html

The section on the siberian huskies is the most interesting.

“Fact is that good and bad genes will be passed on regardless if you linebreed or outcross so bigger importance should be given in my opinion to testing and selecting of breeding material, more so than blaming a way of breeding, be it line/in breeding or outcrossing”
 
Well, yes and no. Yes people have to accept that there is no such thing as dog free of bad genes. But with in/line breeding there is higher chance of doubling up on the same deleterious allele and have a bad gene expressed. And since all dogs carry a number of bad genes, it is a risk that should not be taken lightly.
 
“furthermore I will say what I saidmany time before, if you want to outcross, you need different pure bloodlines available, the only way to maintain that siuation is to line/inbreed”
 
Maybe if we consider a whole breed as one bloodline, then outcrossing would require going to a different breed.
But if you refer to having inbred strains within a breed, then that type of outcrossing would not be meaningful. Several of our current breeds where developed with a small number of founders, lots of inbreeding, followed by other genetic bottlenecks (diseases, WW2, popular sires, etc.), so any strain would be closely related to each other from the start. Then add more use of in/line breeding within each strain, the subsequent loss of genetic diversity (in all of them), and any "outcrossing" between these strains is going to be insignificant, and the breed, as a whole, would still be losing.

To Sunsilver:
I also like his article on population genetics for breeders: http://www.seppalakennels.com/articles/population-genetics-in-practice.htm

as soon as you have bad  genes exposed you can get rid of them, where in outcrossing they will keep slumbering along

outcrossing outside the breed is done for years and generations in KNPV breeding where among others  GSD, malinois, Dutchie, dogbreeds,terriers, and even more  are mixed in, and still all genetic problems occuring in various breeds are popping up in the mixed up outcom, so that is not a solution to get rid of problems

secondly joewulf, if outcossing is the answer for a breed that is far from geneticly stable and exists for about 120 years, can you tell me where animals that are around for millions of years , like crocodiles, sharks etc, where have they been outcrossing to for millions of generations, and why are  these strong species so much stronger fenotypical identical, which is obviously NOT a sign of genetic diversity the outcrosspeople are preaching

said this before also, genetic diversity should be in the breed and NOT in the individual animals


show me a group of german shepherds that show the same genetic uniformity

 
 

Where's that Korean Army Dogs picture when we need it ?  Lotsa LOLs !

I agree with Duke that line breeding is the only way to improve a line. The only thing I would add to that is "selective line breeding". It still all boils down to individuals used in the line. The combinations brought together for the mating. I hear all the time about people mating a female from x line, being bred to a male of x line. All with anticipation of producing uniformity or consistency in the offsprings. While in truth a lot of the individuals are not representative of the line. Some line breedings can be so scattered that for all practical purposes it is not much better than a outcross. Selective line breeding is the only way I know of to manage genetic strengths and weaknesses.
hank

as soon as you have bad  genes exposed you can get rid of them, where in outcrossing they will keep slumbering along

Duke, you obviously didn't read the article I posted. This has been the thinking of dog breeders for many years now, and IT IS WRONG!!

The article exposes that for the fallacy it is. There are many more hidden (recessive) genes than we previously thought. Getting rid of them all would be impossible, and genetic diversity would be so reduced if we did, that it would do great harm to the breed.

Also, when a harmful or undesirable gene is exposed, you have to remember that the parents of the pups, and a certain percentage of the offspring who APPEAR to be unaffected will be carriers, and capable of passing the gene on! So if you TRULY want to get rid of that gene, you have to do some serious culling of your stock!

If you get rid of recessive genes, the gene pool becomes more homozygous, meaning the same alleles are present at most of the loci of the genes. Studies have show heterozygosity is actually an advantage to the animal population. Some genes that are harmful in their homozygous state actually give an advantage in their heterozygous state. To give an example from human populations, the gene for sickle cell anemai can be deadly in its homozygous state, but in its heterozygous state (one normal allele, on sickle cell allele) it helps provide immunity to malaria!)  Scientists are discovering there are many more alleles like that. Just because an allele is recessive does NOT mean it is 'dormant'. Many recessive alleles still do have a job to do.

From a evolutionary point of view, this makes good sense to me. If the whole population of animals were homozygous at all loci of their genes, there would be no 'hidden' genes that could pop out to provide genetic variability in case the environment suddenly changed. There would be no 'new' characteristics that could provide an advantage to certain members of the species to cope with changing conditions. A good example of this would be the pepper moth in England. The light form of the moth resembles a lichen covered tree trunk. There is a dark form of the moth, which comes from a recessive allele. When England became industrialized during the industrial revolution, the lichens were killed off by air pollution, and the trunks of the trees were darkened with soot. This gave the dark form of the moth an advantage when it came to hiding from predators, and the dark form became the most common one in the population.

Duke, geneticists have found that horses and cows (zebras are in the same genus as horses) do not have the same genetic variability that dogs do. It is impossible to breed horses (and zebras) to get the same remarkable variability you see in domestic dogs. A recent National Geographic special explained this was due to dogs having multiple copies of many of their genes, making their genomes far more easy to manipulate. Zebras have also proven almost impossible to domesticate, which could be a result of the uniformity of their genome! None of the traits present in the genome allow for them to submit to being easily handled by humans.

Honestly, we DO need to listent to the geneticists! The strides that have been made in genetics in the last 40 years are mind-blowing. If I could go back to university and do my science degree all over again, this would be the area I'd be most interested in studying!

The breeding principles we are applying to our dogs are still based on what was known about genetics back in the Victorian era. We need to radically change our thinking. Breeds can and do become extinct. Take a look at this book, published in 1915, and notice just how many of these breeds are ones you've never heard of before!  They are either extinct, or so uncommon that they are virtually unknown outside their home country.
http://www.archive.org/stream/dogsofallnations00masorich#page/n7/mode/2up