I didn't say there was, they're 2 seperate examples. Again I have to disagree, just because the dog is fit, doesn't mean it's healthy.

Yes breeding within a closed gene pool will always increase health problems, but as I've said opening the gene pool and getting rid of individual breeds is never going to happen, so the idea of breeding healthy mutts is a moot point so to speak.

DNA testing can gradually remove carriers from a breeding population, it doesn't automatically exclude animals. Such DNA testing has got to be a good thing as, without it, in effect, you don't know what you're breeding due to the nature of the carrier gene! A few generations of healthy dogs proves nothing when a disease can hide away for many, many generations. It may only pop up every now and then, but at the end of the day you've still ended up breeding affected pups purely because you refused to health test. It's a preventative measure, why ignore it!

Also, personally, I don't think the gene pools of the more common breeds is really relevant. IMO it's the unnecessary in breeding and close line breeding that's causing more hereditary problems than the size of the gene pool. Think of the thousands of registrations of Labs and Springers (even within the show world) there is, but yet people will always want the latest winner, instead of thinking about the health and longevity of their breed!

I also don't think you can compare humans to dogs either. Dogs are pedigrees, humans are just mongrels!

Opening the gene pool doesn't mean getting rid of breeds. Breeds, or more accurately 'landraces' were in existence long before the advent of pedigree breeding. It's little more than a century since closed registries were set up. Prior to this, breeding was somewhat random and selection was post zygotic as opposed to the pre-zygotic of today.

'Fixing type' has been the mantra of pedigree breeding but this is not how dogs were bred for thousands of years pre 19th century.



Yes of course DNA testing is a good thing. In closely bred populations it is a godsend but it will not restore health to a diminishing gene pool.



Again, closed gene pool breeding does benefit from DNA testing but there are far more diseases than can ever be tested for and the closer the breeding the more these will tend to show up. Outcross breeding reduces the chances of recessive meeting up to produce disease. In addition to this we have ill health that is not controlled directly by gene action.... more to do with diversity, or lack of.

Increased homozygosity of the MHC complex genes is now thought to be a significant factor in the increase in immune mediated diseases. Very significant in many of today's breeds. There is no DNA test that could ever prevent this occuring, only opening up the gene pools would.


The two are intrinsically linked. If you inbreed you are automatically reducing the gene pool and if you breed within a small, closed gene pool, you are automatically inbreeding regardless of what's on the pedigree.


And all the healthier for it

In English please!


Just out of interest, what would you do to improve pedigree breeds then? How would you go about governing the opening of individual gene pools?


How are the gene pools diminishing? Dogs can now be bred fairly easily across the world, making the gene pools expand if anything. I certainly wouldn't say English Springers (or many other breeds for that matter) have a small or diminishing gene pool! Some people seem to think that if a certain line has been free from health problems for generations, then health testing isn't necessary. All I was saying, in the event of the carrier gene, that that's a load of twaddle!



English again please!


Now to me inbreeding is Mother to Son, Father to Daughter. Line breeding Mother to Grandson, Father to Granddaughter etc.

In my experience inbreeding very, very rarely happens, line breeding is more popular and healthier imo. Again I don't think the majority of breeds have a small closed gene pool.

My understanding of the "begininng of the world" was that we all came from the same initial organism and then evolved along different paths, so aren't we all inbred anyway?!


That I definitely disagree with!

In my breed it doesnt matter where in the world you buy the dog if it is from West German lines they are inbred on the same sibblings half sibblings in the 6/7th generations dependent on age. Same again with some of the working lines, so the actualy gene pool is small and it is this that causes some of the genetic mutations and development of new inherent conditions.
The best way forward would be to cross the lines between work/show lines, you may loose type for a few generations but would decrease the incident of inherent conditions.

Sorry. Before the advent of pedigree breeding, it is said that very few intentional matings took place as dogs were more or less freerange and chose their own partners. The fittest and luckiest of the offspring survived and the best workers were retained, and so selected to keep the 'breed' going. This is post zygotic, meaning 'after fertilised egg' as the actual mating partners were not planned and selection was based on the progeny. Pre-zygotic is when matings are planned so the breeding partners are selected.


I think a good start would be for breed clubs to embrace the KC's recent introduction of the scheme to incorporate unregistered dogs into the stud books. From what I gather, there have been applications to do this in the Bearded Collie and Bloodhound. The Beardie one didn't get past the breed club as they regard the working type to be untypical in coat. Actually it's the show type that has incorrect coat according to the standard but that's another matter

The KC info on this - http://www.the-kennel-club.org.uk/pr...q=registration

Another step forward IMO would be to allow cross breeding in varieties such as the Belgian Shepherd, Rough and Smooth Collies, Dachshunds, smooth and lomgcoat Chihuahua etc etc.

Also better education and regulation for judges to reduce the tendency for exaggeration that occurs in many breeds. THe GSD for instance has a wide gene pool but because of extreme types, we have different factions that breed only within their own type, so restricting their individual gene pools.



The diversity of a gene pool is dependent on the number and relatedness of the founder animals, and the breeding stratergies since foundation. In breeds that have a small number of founders, or which have gone through a bottleneck, the gene pool will be reduced regardless of breeding stratergy. It matters not that you can now go to the four corners of the earth for 'unrelated' lines, these will all have originated from the same gene base so will be close genetically whether it show in the pedigree or not. The only way to expand the breed gene pool is to outcross to a different breed.

Inbreeding does actually reduce a breeds diversity because whilst selecting dogs of close relation, you are discarding dogs that are less related, so in effect reducing the number of alternative alleles ('genes') in the population.


I'm going to do this one with a link. C A Sharp, an Aussie breeder, scientist and writer, well respected on both sides of the Atlantic - http://www.ashgi.org/articles/immune_rising_storm.htm


That's the generally accepted definition of inbreeding but that only accounts for what's in the immediate family. A more efficent way of calculating involves the COI - coefficient of inbreeding, which can inccorporate many generations and produce an estimated degree of homozygosity based on this. In could be that some dogs that have no duplications in a five generation pedigree are actually higher in COI than dogs from a close breeding on paper.


Yes, good point! When life began the organism would have been under the control of just a handful of genes and it has taken billions of years for the development of more complex life forms that require thousands of genes arranged in chromosomal formation. New genes and alleles are formed by mutations and these occur at a more or less predictable rate.

It has taken the wolf many hundreds of thousands of years to develop, and the dog, thousands of years since domestication. It's not yet known for sure how diverse the domestic dog foundation was but there has undoubtedly been new input from the wolf over the millenia which has produced a diverse gene pool.

Human interference in creating breeds in the last century has diminished the individual population gene pools to such an extent that the mutation rate has no hope of compensating within those breeds.


We may not be particularly healthy as a species but that's more to do with lifestyle and our own polution than genetic factors. The human race has a massive number of identified genetic defects compared to dogs, yet dogs have a much higher incidence of genetic illhealth.

Ahmen to that! I'm hoping to include some working lines in my dogs to bring back some of the natural hunting ability lost from the show type ESS.
Sounds pretty sensible to me.

Can't disagree with that, all the better for the dogs. But of course there is one major flaw - people would have to start thinking of the dog first and not the rosettes hanging on their wall. Knowing the human race, that would take alot of persuasion!

I see what you're saying there, but as I've said before taking pedigrees back to crossbreeds just isn't going to happen. I agree with trying to widen the gene pools, but you have to be realistic.


Thanks for the link, will have a gander tomorrow!


Ah I'm guessing this is the percentage rate sometimes quoted with pedigrees? What, in your mind, is the best percentage to have? Or to put it better, the highest percentage you would be happy with (again being realistic within the pedigree breeds! ).


Very interesting.

Yeah like I said, we're all mongrels!

I don't think this is something you can do on an individual basis as it requires a joint effort within the breed but the general impression that I get from my readings is that the lower it is, the better. I don't actually see the odd inbred litter now and again, for the right reason, as anything to scream about so long as all relevant health testing is done, and with good knowledge of the bloodlines. What is more detrimental IMO opinion is continuous 'line breeding' without incorporating outcrossing. It eats away insidiously at the gene pool whilst not being thought of as particularly harmful, as a closer inbreeding would be by some.

Yes, COI is usually expressed as a percentage. Father x daughter, mother x son and brother x sister would each be 25%, assuming there was no other inbreeding in the calculation.