Mating

[Steve]

Surely the answer to that is education to try to help people not make good informed decisions coupled with a a greater sharing of knowledge.- which is why my answer is that it depends on your goals and what you know about what is or may show up in the lines - good and bad. There are many things that testing and DNA is not going to be the answer for so the only hope we have of doing something to prevent problems is to use breeding systems as a tool. You can keep out crossing and make these things less common or less likely to appear but they are still there and can turn up anywhere. If there is a tool available to us which has the potential of wiping it out of our lines and if we work together - our breeds why not use it?

[Steve]

O.K. so if in - breeding is such a terrible thing how do we understand how some of the cultures which have had the most impact on mankind came about. Many developed in naturally or artificially confined areas For example Crete and Japan, Peninsulas like India, Greece, and Italy,naturally enclosed areas like Peru, Mesopotamia, and Egypt, and more or less artificially enclosed areas like China and Palestine . History tells us that these people were secluded they had no choice but to inbreed and close linebreed;

Humans who gained certain unique qualities usually had an instinct to separate themselves and even in primitive societies it's been well documented.

The Egyptians, Greeks, Jews all not only in bred but were also incestuous.

Take a different perspective on how you look at nature and you will see Animals striving everywhere to produce homozygosity. They don't have any instinctive safeguard against incestuous mating. Among antelopes incestuous matings are the rule. The African reedbuck, for instance, has two young at a birth, male and female, which mate together when mature. Only when one happens to die by accident does out- or cross-breeding occur and this is true of the smaller antelopes too, it's the same with red deer. Brother and sister tigers mate as the norm and among African buffaloes, breeding occurs mainly among the immediate offspring of the same cow. The cattle from La Plata in the Falkland Islands, not only quickly multiplied from just a few , but they also broke up into smaller herdsaccording to colour, and the close inbreeding became more intensive because ofthe cattle's own instincts.

Many animals do chase off the younger males and don't let any new comers in so the, males mate with their own daughters.

In nature among some monkeys constant matings between the head of the horde and his daughters, sisters and other close relations, happen. Among most animals,including elephants , the leading male mates with his daughters,grand-daughters, and great-grand-daughters, as long as he is able to keep other males away. Even when he isn't strong any more that doesn't stop the incest because usually it will be one of his sons which take his place.

Have a look at the rabbits and foxes of Australia and these are all the offspring of just a few individuals

In New Zealand the red deer began as 3 and were introduced in the 1800's from England and last count about ten years ago the herd numbered over 5,000. They show no signs of disease and they are superior in vigour and health to the original parent stock.

.A fellow called Kronacher, starting with one male and three females (a motherand two daughters) of ordinary goats, and in bred for eight generations,without any loss of size, physical development, milking capacity, fertility or vitality. In fact their fertility tended to increase. And he declared that in this case he practised no selection whatever.

In 1916 Professor Castle stated that he had successfully bred Drosophila, brother and sister, for 59 generations, without obtaining any diminution in either vigour or fertility. Moenkhaus crossed the same fly, brother and sister, for 75 generations, without harmful consequences.Hyde and Schultze achieved the same result with mice. Castle tried rats, and Popenoe guinea-pigs, and both concluded that no deleterious effects could be ascribed to the in bred system of mating. King experimented with white rats,mating brother and sister regularly for 22 generations, and among these inbred rats some were obtained which proved actually superior to the stock rats from which they had sprung. The males were 15 per cent. heavier, and the females 3per cent., while the fertility was nearly 8 per cent. Higher.

In old Egypt,national law didn't allow mixing with foreigners, incest was common both among the people and within the ruler groups. Cleopatra, famous for her wit, beauty and intelligence, was the daughter of a brother and sister,great-grand-daughter of another brother and sister, and a great-great-grand-daughter of Berenice who was both cousin and sister to her husband. In Britain,as late as fifth century, Vortigern married his own daughter. Nor could the practice have been condemned, since the son of this sinful union was none other than St. Faustus. The ancient Irish married without distinction their mothers and sisters, and it was customary for the ancient Germans to marry their sisters. There is overwhelming evidence that the Peruvians were strictly inbred . The Incas, refused to mix their blood and married their sisters; More modern studies in human population genetics are The Pitcairn islanders, the Kisar Hybrids, the Bastards of Rehoboth, and the people of the island of Batz, all of whom are examples of human breeding with close inbreeding without harmful results. Even in tribes and races where incest is illegal, often the rulers or chiefs deliberately breach laws to keep their blood pure. For instance in several countries, marriage with half-sisters is forbidden, but the King always marries his half-sister. may marry his sister and his daughter. Eg.Cambodia, the chiefs of the Marianne and Ladrone Islands,in Hawaii, Nukuhiva, Tahiti and Madagascar, and it was also true of the Northern American Indians of New England. Nor are the people who do inbreed degenerate or diseased, and travellers comment on their great vigour and beauty.

With the Fijians — those stocks which have adhered to the ancestral custom requiring first-cousin marriages, are very much the superiors from every physical point of view of those who no longer practise, or else forbid,first-cousin marriages, and the latter are even said to be dying out, while the former have a higher birth rate and greater vitality.

The Bataks of Sumatra, who also habitually marry their first-cousins, are some of the healthiest people in the Indian Archipelago. The chiefs in Polynesia and New Zealand have all been noticed for their superior height, looks and vigour. And throughout Polynesia the closest inbreeding inmating is among the chiefs.

Therefore, humans are just as capable as some of the animals of thriving onclose inbred matings, if the strains are pure; and in fact when a human stockhas become quite pure close inbreeding is actually the only means ofmaintaining it.

I also remember living in a small community in northern NSW where some research on incest was being done in an isolated community near to us where every one ofthe residents were related to each other but they were definitely a prime example of what stock NOT to use as your foundation stock. I guess the movie deliverance showed that too.

So - There is a difference in how a good purebred modern dog breeder and mos tother humans in charge of breeding practices in other animals proceed. Profiling a pedigree which can identify recessives, mutations, diseases etc before a mate is chosen can have a huge impact. Then of course we have all the modern technologies and resources too such as DNA X rays, scans and specialist testing we can use. We're not considering animals which are inbred from a natural occurrence due to isolation etc which is usual in studies with population genetics but we are manipulating which mates to use. Without manipulating the matings things such as environmental factors [ such as loss of habitat]deficiencies in soils which lead to nutritional deficiencies etc have to also be considered as to how they may affect the study results. Usually when a scientist goes after an answer only one variable is looked at when in fact their study results may have been impacted by many others

Next - not only are we talking about breeding animals of the same species but many of the genetic issues modern purebred breeders have to contend with are not recessive issues. Polygenic genes cause us more grief than most others and the contributing factors are in all dogs .So outcrossing doesn't eliminate the potentials for seeing genes which are affected by things other than recessives BECAUSE we are still breeding the same species. If the unrelated strains share common genes for genetic disorders, no amount of hybrid vigour will over ride the risk of the disorder showing up.

Short answer is that there is nothing "wrong" with breeding any two animals of any degree of relatedness, as long as the breeder realizes the potential risks and benefits of the mating. Any level of inbreeding does carry some risk (the risk that one or more formerly hidden recessive traits will be expressed in the homozygous offspring), but there is also the potential for benefits .

Each breeder has to weigh the potential costs and benefits and assess whichstrategy best fits his or her long term goals and interests and they shouldn't be frightened off making those decisions by propaganda spread by those tryingto discredit what a purebred breeder does in order to promote crossbreeds.

Edited January 15, 2012 by Steve

[Steve]

To me, the interesting question is "how has low diversity affected breeds that were founded by very small populations". I think the jury is still out on this. But in such cases, even if the five generation COI looks good, the COI that would be derived by going all the way back to the founding of the breed would be very high. Here the problem isn't matings too close on the family tree, but the difficulty of finding any way to avoid breeding dogs who are genetically very closely related.

So how far do we need to play with this - Last time I looked the human race had one of four women in common didn't they? Dogs move through generations a lot quicker than humans. What is your COI ? i don't know what mine is or what my ex husbands was but we each turned out to carry the same gene which causes haemochromotosis . I have 5 of 8 kids affected by it - so no doubt if we went back in our pedigrees far enough we would see where it came from - one common ancestor. If I had of known the lines and the pedigree i could have avoided that mating and prevent my kids from suffering - there was I thinking I was safe with an out cross.

Lets not forget that humans in Australia can legally marry their cousins.

the only time COI are helpful is if we know what else is in there.

[dragonwoman]

O.K. so if in - breeding is such a terrible thing how do we understand how some of the cultures which have had the most impact on mankind came about. Many developed in naturally or artificially confined areas For example Crete and Japan, Peninsulas like India, Greece, and Italy,naturally enclosed areas like Peru, Mesopotamia, and Egypt, and more or less artificially enclosed areas like China and Palestine . History tells us that these people were secluded they had no choice but to inbreed and close linebreed;

Humans who gained certain unique qualities usually had an instinct to separate themselves and even in primitive societies it's been well documented.

The Egyptians, Greeks, Jews all not only in bred but were also incestuous.

Take a different perspective on how you look at nature and you will see Animals striving everywhere to produce homozygosity. They don't have any instinctive safeguard against incestuous mating. Among antelopes incestuous matings are the rule. The African reedbuck, for instance, has two young at a birth, male and female, which mate together when mature. Only when one happens to die by accident does out- or cross-breeding occur and this is true of the smaller antelopes too, it's the same with red deer. Brother and sister tigers mate as the norm and among African buffaloes, breeding occurs mainly among the immediate offspring of the same cow. The cattle from La Plata in the Falkland Islands, not only quickly multiplied from just a few , but they also broke up into smaller herdsaccording to colour, and the close inbreeding became more intensive because ofthe cattle's own instincts.

Many animals do chase off the younger males and don't let any new comers in so the, males mate with their own daughters.

In nature among some monkeys constant matings between the head of the horde and his daughters, sisters and other close relations, happen. Among most animals,including elephants , the leading male mates with his daughters,grand-daughters, and great-grand-daughters, as long as he is able to keep other males away. Even when he isn't strong any more that doesn't stop the incest because usually it will be one of his sons which take his place.

Have a look at the rabbits and foxes of Australia and these are all the offspring of just a few individuals

In New Zealand the red deer began as 3 and were introduced in the 1800's from England and last count about ten years ago the herd numbered over 5,000. They show no signs of disease and they are superior in vigour and health to the original parent stock.

.A fellow called Kronacher, starting with one male and three females (a motherand two daughters) of ordinary goats, and in bred for eight generations,without any loss of size, physical development, milking capacity, fertility or vitality. In fact their fertility tended to increase. And he declared that in this case he practised no selection whatever.

In 1916 Professor Castle stated that he had successfully bred Drosophila, brother and sister, for 59 generations, without obtaining any diminution in either vigour or fertility. Moenkhaus crossed the same fly, brother and sister, for 75 generations, without harmful consequences.Hyde and Schultze achieved the same result with mice. Castle tried rats, and Popenoe guinea-pigs, and both concluded that no deleterious effects could be ascribed to the in bred system of mating. King experimented with white rats,mating brother and sister regularly for 22 generations, and among these inbred rats some were obtained which proved actually superior to the stock rats from which they had sprung. The males were 15 per cent. heavier, and the females 3per cent., while the fertility was nearly 8 per cent. Higher.

In old Egypt,national law didn't allow mixing with foreigners, incest was common both among the people and within the ruler groups. Cleopatra, famous for her wit, beauty and intelligence, was the daughter of a brother and sister,great-grand-daughter of another brother and sister, and a great-great-grand-daughter of Berenice who was both cousin and sister to her husband. In Britain,as late as fifth century, Vortigern married his own daughter. Nor could the practice have been condemned, since the son of this sinful union was none other than St. Faustus. The ancient Irish married without distinction their mothers and sisters, and it was customary for the ancient Germans to marry their sisters. There is overwhelming evidence that the Peruvians were strictly inbred . The Incas, refused to mix their blood and married their sisters; More modern studies in human population genetics are The Pitcairn islanders, the Kisar Hybrids, the Bastards of Rehoboth, and the people of the island of Batz, all of whom are examples of human breeding with close inbreeding without harmful results. Even in tribes and races where incest is illegal, often the rulers or chiefs deliberately breach laws to keep their blood pure. For instance in several countries, marriage with half-sisters is forbidden, but the King always marries his half-sister. may marry his sister and his daughter. Eg.Cambodia, the chiefs of the Marianne and Ladrone Islands,in Hawaii, Nukuhiva, Tahiti and Madagascar, and it was also true of the Northern American Indians of New England. Nor are the people who do inbreed degenerate or diseased, and travellers comment on their great vigour and beauty.

With the Fijians — those stocks which have adhered to the ancestral custom requiring first-cousin marriages, are very much the superiors from every physical point of view of those who no longer practise, or else forbid,first-cousin marriages, and the latter are even said to be dying out, while the former have a higher birth rate and greater vitality.

The Bataks of Sumatra, who also habitually marry their first-cousins, are some of the healthiest people in the Indian Archipelago. The chiefs in Polynesia and New Zealand have all been noticed for their superior height, looks and vigour. And throughout Polynesia the closest inbreeding inmating is among the chiefs.

Therefore, humans are just as capable as some of the animals of thriving onclose inbred matings, if the strains are pure; and in fact when a human stockhas become quite pure close inbreeding is actually the only means ofmaintaining it.

I also remember living in a small community in northern NSW where some research on incest was being done in an isolated community near to us where every one ofthe residents were related to each other but they were definitely a prime example of what stock NOT to use as your foundation stock. I guess the movie deliverance showed that too.

So - There is a difference in how a good purebred modern dog breeder and mos tother humans in charge of breeding practices in other animals proceed. Profiling a pedigree which can identify recessives, mutations, diseases etc before a mate is chosen can have a huge impact. Then of course we have all the modern technologies and resources too such as DNA X rays, scans and specialist testing we can use. We're not considering animals which are inbred from a natural occurrence due to isolation etc which is usual in studies with population genetics but we are manipulating which mates to use. Without manipulating the matings things such as environmental factors [ such as loss of habitat]deficiencies in soils which lead to nutritional deficiencies etc have to also be considered as to how they may affect the study results. Usually when a scientist goes after an answer only one variable is looked at when in fact their study results may have been impacted by many others

Next - not only are we talking about breeding animals of the same species but many of the genetic issues modern purebred breeders have to contend with are not recessive issues. Polygenic genes cause us more grief than most others and the contributing factors are in all dogs .So outcrossing doesn't eliminate the potentials for seeing genes which are affected by things other than recessives BECAUSE we are still breeding the same species. If the unrelated strains share common genes for genetic disorders, no amount of hybrid vigour will over ride the risk of the disorder showing up.

Short answer is that there is nothing "wrong" with breeding any two animals of any degree of relatedness, as long as the breeder realizes the potential risks and benefits of the mating. Any level of inbreeding does carry some risk (the risk that one or more formerly hidden recessive traits will be expressed in the homozygous offspring), but there is also the potential for benefits .

Each breeder has to weigh the potential costs and benefits and assess whichstrategy best fits his or her long term goals and interests and they shouldn't be frightened off making those decisions by propaganda spread by those tryingto discredit what a purebred breeder does in order to promote crossbreeds.

Excellent post I think some of the shivers through the general population when inbreeding is mentioned is that they could not imagine themselves doing it!! The cultures mentioned above would have been young and vigorous, mating early and mating often would probably have been the go and the duds would not have survived to add to the gene pool. The breeders would have been the survivors of wars and hardships and therefore quality stock. With our dogs, it so not so much who you are breeding to who but what you are breeding to what, and with modern testing and hopefully transparency between breeders, informed close mating decisions should be the province of those who seriously care about their breed, not the knee jerkers who represent us and make stupid populist regulations

I feel more comfortable about mating my dogs to rellies with well-documented health and temperament histories than with other outside dogs, I know pretty well what I will get. And if something odd turns up, that is just something more to add to my pool of knowledge about what is running around my yard

DW

[Sandra777]

Does this contravene the new regulations re breeding (line-breeding) which came into force as at July 2011 I believe?

No. The regulation prohibits brother-sister father-daughter and mother-son matings only.

Is this too close - IMO it depends totally on the knowledge you have about the good and bad points (especially the bad health points :) ) of the dogs.

No mating is too close or "just right" based solely on the relationship between the dogs, it depends on so much more than that.

[sandgrubber]

To me, the interesting question is "how has low diversity affected breeds that were founded by very small populations". I think the jury is still out on this. But in such cases, even if the five generation COI looks good, the COI that would be derived by going all the way back to the founding of the breed would be very high. Here the problem isn't matings too close on the family tree, but the difficulty of finding any way to avoid breeding dogs who are genetically very closely related.

So how far do we need to play with this - Last time I looked the human race had one of four women in common didn't they? Dogs move through generations a lot quicker than humans. What is your COI ? i don't know what mine is or what my ex husbands was but we each turned out to carry the same gene which causes haemochromotosis . I have 5 of 8 kids affected by it - so no doubt if we went back in our pedigrees far enough we would see where it came from - one common ancestor. If I had of known the lines and the pedigree i could have avoided that mating and prevent my kids from suffering - there was I thinking I was safe with an out cross.

Lets not forget that humans in Australia can legally marry their cousins.

the only time COI are helpful is if we know what else is in there.

I don't know where you looked to see the human race had four women in common. How does this true up with recent discoveries that we all carry a bit of Neanderthal?

As for COI: Good you asked. My maternal grandparents were first cousins and I have inherited a couple family conditions. 1) 14 of my permanent teeth never came in, and I've required implants and bridges to maintain a fully functional mouth. An aunt and great aunt were also born without permenant teeth. 2) I show a biological false positive on the Wasserman test . . . as did my grandmother. Knock on wood . . . the latter is said to be associated with autoimmune conditions, but so far I haven't suffered any.

Edited January 15, 2012 by sandgrubber

[sandgrubber]

To me, the interesting question is "how has low diversity affected breeds that were founded by very small populations". I think the jury is still out on this. But in such cases, even if the five generation COI looks good, the COI that would be derived by going all the way back to the founding of the breed would be very high. Here the problem isn't matings too close on the family tree, but the difficulty of finding any way to avoid breeding dogs who are genetically very closely related.

So how far do we need to play with this - Last time I looked the human race had one of four women in common didn't they? Dogs move through generations a lot quicker than humans. What is your COI ? i don't know what mine is or what my ex husbands was but we each turned out to carry the same gene which causes haemochromotosis . I have 5 of 8 kids affected by it - so no doubt if we went back in our pedigrees far enough we would see where it came from - one common ancestor. If I had of known the lines and the pedigree i could have avoided that mating and prevent my kids from suffering - there was I thinking I was safe with an out cross.

Lets not forget that humans in Australia can legally marry their cousins.

the only time COI are helpful is if we know what else is in there.

I don't know where you looked to see the human race had four women in common. How does this true up with recent discoveries that we all carry a bit of Neanderthal?

As for COI: Good you asked. My maternal grandparents were first cousins and I have inherited a couple family conditions. 1) 14 of my permanent teeth never came in, and I've required implants and bridges to maintain a fully functional mouth. An aunt and great aunt were also born without permenant teeth. 2) I show a biological false positive on the Wasserman test . . . as was my grandmother. Knock on wood . . . the latter is said to be associated with autoimmune conditions, but so far I haven't suffered any.

Studies of inbred human populations tend to show negative health consequences. See, eg.,

http://www.ncbi.nlm....les/PMC2080450/

I don't know where you got your information about human groups that practice consanguineous marriage. The patterns are complex. . . . and the practices are widespread. See, eg:

www.consang.net/images/d/dd/01AHBWeb3.pdf

If you look at populations where the pedigrees of humans can be traced, eg, royal families in Europe, I think you'll find that inbreeding has created health and fertility problems.

Island populations with small founder populations are commonly highly inbred. And they often go extinct.

Edited January 15, 2012 by sandgrubber

[Steve]

Sandgrubber - no one is saying that inbreeding doesn't carry risks and as usual when discussing genetics even the "experts" cant agree .The point is that if its used in dog breeding , selectively with knowledge and specific goals it can be a good thing and just because a dog is closely related to another dog shouldn't automatically discount it as a possible mating.

the fact of the matter is that we do inbreed - its how we got our breeds , how we got health issues in our breeds and if we are to maintain viability of our breeds it needs to be used as a tool sometimes to take us where we want to go -

to inbred animals which allow us to be able to predict their characteristics so we can place puppies in homes which are most suited to them and their traits and characteristics.

To date we have selected for the wrong reasons - how the dog looks and overlooked other things which we should have been more aware of. So if someone is now considering a close mating with specific goals and knowledge of the risks

it shouldn't be out of hand discounted simply because of how close it is.

The basic question should be what we are selecting for not whether they are closely related and we have to simply own up to the fact that purebred dogs are inbred - its what we do - and it is what we have always done - just as any other breeders does of any other purebred animal - because the alternative is a generic dogs with little or no predictability including no ability to know what to test for or try to identify and eliminate .

In breeding has been pushed as being all evil and the root cause of pedigree dogs ill health - it probably is but its not because they are inbred its because of what they have selected for.

We live in exciting times with the ability to access greater knowledge and new science to enable us to score and tests and eliminate carriers etc and a time where in breeding could be used to ensure less dogs suffer as long as we make our choices with knowledge.

[oakway]

Maybe we should look towards Mendelsohn's Pea.

I agree with Steve entirely.

[sandgrubber]

Sandgrubber - no one is saying that inbreeding doesn't carry risks and as usual when discussing genetics even the "experts" cant agree .The point is that if its used in dog breeding , selectively with knowledge and specific goals it can be a good thing and just because a dog is closely related to another dog shouldn't automatically discount it as a possible mating.

the fact of the matter is that we do inbreed - its how we got our breeds , how we got health issues in our breeds and if we are to maintain viability of our breeds it needs to be used as a tool sometimes to take us where we want to go -

to inbred animals which allow us to be able to predict their characteristics so we can place puppies in homes which are most suited to them and their traits and characteristics.

To date we have selected for the wrong reasons - how the dog looks and overlooked other things which we should have been more aware of. So if someone is now considering a close mating with specific goals and knowledge of the risks

it shouldn't be out of hand discounted simply because of how close it is.

The basic question should be what we are selecting for not whether they are closely related and we have to simply own up to the fact that purebred dogs are inbred - its what we do - and it is what we have always done - just as any other breeders does of any other purebred animal - because the alternative is a generic dogs with little or no predictability including no ability to know what to test for or try to identify and eliminate .

In breeding has been pushed as being all evil and the root cause of pedigree dogs ill health - it probably is but its not because they are inbred its because of what they have selected for.

We live in exciting times with the ability to access greater knowledge and new science to enable us to score and tests and eliminate carriers etc and a time where in breeding could be used to ensure less dogs suffer as long as we make our choices with knowledge.

I made no blanket statement against in/line breeding as I'm getting different opinions for different sides and haven't had the time to read the huge amount of information carefully.

I am quite ready to say that close line breeding can unearth nasty recessive traits, and should not be undertaken by 'beginning' breeders who find it convenient to use a dog they have bred over his mother or half sister, even if he seems healthy and is a lovely dog.

The canine genome has around 3 billion base pairs. The general effect of inbreeding is to make an increasing number of those base pairs homozygous. Line- or inbreeding with selection may help in getting the 'baddies' to drop out of the target base pairs, leaving the DNA more homozygous for the desired state of the target allele. How many traits are you breeding for . . . I'd guess less than 500. What happens to the 3 billion minus 500 base pairs? They also become more homozygous. Eventually this will lead to problems.

I came across a table for pup survival rate vs COI. Unfortunately, the blogger didn't note his source. If you have better data, please post it. But until someone comes up with verified numbers, this is what I accept as a tentative hypothesis:

COI: survival rate

<0.19: 75%

0.25-0.67: 51%

>0.67: 25%

source: http://www.astraean....g-yourself.html

Edited January 15, 2012 by sandgrubber

[LizT]

O.K. so if in - breeding is such a terrible thing how do we understand how some of the cultures which have had the most impact on mankind came about. Many developed in naturally or artificially confined areas For example Crete and Japan, Peninsulas like India, Greece, and Italy,naturally enclosed areas like Peru, Mesopotamia, and Egypt, and more or less artificially enclosed areas like China and Palestine . History tells us that these people were secluded they had no choice but to inbreed and close linebreed;

Humans who gained certain unique qualities usually had an instinct to separate themselves and even in primitive societies it's been well documented.

The Egyptians, Greeks, Jews all not only in bred but were also incestuous.

Take a different perspective on how you look at nature and you will see Animals striving everywhere to produce homozygosity. They don't have any instinctive safeguard against incestuous mating. Among antelopes incestuous matings are the rule. The African reedbuck, for instance, has two young at a birth, male and female, which mate together when mature. Only when one happens to die by accident does out- or cross-breeding occur and this is true of the smaller antelopes too, it's the same with red deer. Brother and sister tigers mate as the norm and among African buffaloes, breeding occurs mainly among the immediate offspring of the same cow. The cattle from La Plata in the Falkland Islands, not only quickly multiplied from just a few , but they also broke up into smaller herdsaccording to colour, and the close inbreeding became more intensive because ofthe cattle's own instincts.

Many animals do chase off the younger males and don't let any new comers in so the, males mate with their own daughters.

In nature among some monkeys constant matings between the head of the horde and his daughters, sisters and other close relations, happen. Among most animals,including elephants , the leading male mates with his daughters,grand-daughters, and great-grand-daughters, as long as he is able to keep other males away. Even when he isn't strong any more that doesn't stop the incest because usually it will be one of his sons which take his place.

Have a look at the rabbits and foxes of Australia and these are all the offspring of just a few individuals

In New Zealand the red deer began as 3 and were introduced in the 1800's from England and last count about ten years ago the herd numbered over 5,000. They show no signs of disease and they are superior in vigour and health to the original parent stock.

.A fellow called Kronacher, starting with one male and three females (a motherand two daughters) of ordinary goats, and in bred for eight generations,without any loss of size, physical development, milking capacity, fertility or vitality. In fact their fertility tended to increase. And he declared that in this case he practised no selection whatever.

In 1916 Professor Castle stated that he had successfully bred Drosophila, brother and sister, for 59 generations, without obtaining any diminution in either vigour or fertility. Moenkhaus crossed the same fly, brother and sister, for 75 generations, without harmful consequences.Hyde and Schultze achieved the same result with mice. Castle tried rats, and Popenoe guinea-pigs, and both concluded that no deleterious effects could be ascribed to the in bred system of mating. King experimented with white rats,mating brother and sister regularly for 22 generations, and among these inbred rats some were obtained which proved actually superior to the stock rats from which they had sprung. The males were 15 per cent. heavier, and the females 3per cent., while the fertility was nearly 8 per cent. Higher.

In old Egypt,national law didn't allow mixing with foreigners, incest was common both among the people and within the ruler groups. Cleopatra, famous for her wit, beauty and intelligence, was the daughter of a brother and sister,great-grand-daughter of another brother and sister, and a great-great-grand-daughter of Berenice who was both cousin and sister to her husband. In Britain,as late as fifth century, Vortigern married his own daughter. Nor could the practice have been condemned, since the son of this sinful union was none other than St. Faustus. The ancient Irish married without distinction their mothers and sisters, and it was customary for the ancient Germans to marry their sisters. There is overwhelming evidence that the Peruvians were strictly inbred . The Incas, refused to mix their blood and married their sisters; More modern studies in human population genetics are The Pitcairn islanders, the Kisar Hybrids, the Bastards of Rehoboth, and the people of the island of Batz, all of whom are examples of human breeding with close inbreeding without harmful results. Even in tribes and races where incest is illegal, often the rulers or chiefs deliberately breach laws to keep their blood pure. For instance in several countries, marriage with half-sisters is forbidden, but the King always marries his half-sister. may marry his sister and his daughter. Eg.Cambodia, the chiefs of the Marianne and Ladrone Islands,in Hawaii, Nukuhiva, Tahiti and Madagascar, and it was also true of the Northern American Indians of New England. Nor are the people who do inbreed degenerate or diseased, and travellers comment on their great vigour and beauty.

With the Fijians — those stocks which have adhered to the ancestral custom requiring first-cousin marriages, are very much the superiors from every physical point of view of those who no longer practise, or else forbid,first-cousin marriages, and the latter are even said to be dying out, while the former have a higher birth rate and greater vitality.

The Bataks of Sumatra, who also habitually marry their first-cousins, are some of the healthiest people in the Indian Archipelago. The chiefs in Polynesia and New Zealand have all been noticed for their superior height, looks and vigour. And throughout Polynesia the closest inbreeding inmating is among the chiefs.

Therefore, humans are just as capable as some of the animals of thriving onclose inbred matings, if the strains are pure; and in fact when a human stockhas become quite pure close inbreeding is actually the only means ofmaintaining it.

I also remember living in a small community in northern NSW where some research on incest was being done in an isolated community near to us where every one ofthe residents were related to each other but they were definitely a prime example of what stock NOT to use as your foundation stock. I guess the movie deliverance showed that too.

So - There is a difference in how a good purebred modern dog breeder and mos tother humans in charge of breeding practices in other animals proceed. Profiling a pedigree which can identify recessives, mutations, diseases etc before a mate is chosen can have a huge impact. Then of course we have all the modern technologies and resources too such as DNA X rays, scans and specialist testing we can use. We're not considering animals which are inbred from a natural occurrence due to isolation etc which is usual in studies with population genetics but we are manipulating which mates to use. Without manipulating the matings things such as environmental factors [ such as loss of habitat]deficiencies in soils which lead to nutritional deficiencies etc have to also be considered as to how they may affect the study results. Usually when a scientist goes after an answer only one variable is looked at when in fact their study results may have been impacted by many others

Next - not only are we talking about breeding animals of the same species but many of the genetic issues modern purebred breeders have to contend with are not recessive issues. Polygenic genes cause us more grief than most others and the contributing factors are in all dogs .So outcrossing doesn't eliminate the potentials for seeing genes which are affected by things other than recessives BECAUSE we are still breeding the same species. If the unrelated strains share common genes for genetic disorders, no amount of hybrid vigour will over ride the risk of the disorder showing up.

Short answer is that there is nothing "wrong" with breeding any two animals of any degree of relatedness, as long as the breeder realizes the potential risks and benefits of the mating. Any level of inbreeding does carry some risk (the risk that one or more formerly hidden recessive traits will be expressed in the homozygous offspring), but there is also the potential for benefits .

Each breeder has to weigh the potential costs and benefits and assess whichstrategy best fits his or her long term goals and interests and they shouldn't be frightened off making those decisions by propaganda spread by those tryingto discredit what a purebred breeder does in order to promote crossbreeds.

On the same token wasn't it inbreeding in Switzerland that saw an increase in the incidence of hydrocephalus in the populace last centuary?

[Steve]

Sandgrubber - no one is saying that inbreeding doesn't carry risks and as usual when discussing genetics even the "experts" cant agree .The point is that if its used in dog breeding , selectively with knowledge and specific goals it can be a good thing and just because a dog is closely related to another dog shouldn't automatically discount it as a possible mating.

the fact of the matter is that we do inbreed - its how we got our breeds , how we got health issues in our breeds and if we are to maintain viability of our breeds it needs to be used as a tool sometimes to take us where we want to go -

to inbred animals which allow us to be able to predict their characteristics so we can place puppies in homes which are most suited to them and their traits and characteristics.

To date we have selected for the wrong reasons - how the dog looks and overlooked other things which we should have been more aware of. So if someone is now considering a close mating with specific goals and knowledge of the risks

it shouldn't be out of hand discounted simply because of how close it is.

The basic question should be what we are selecting for not whether they are closely related and we have to simply own up to the fact that purebred dogs are inbred - its what we do - and it is what we have always done - just as any other breeders does of any other purebred animal - because the alternative is a generic dogs with little or no predictability including no ability to know what to test for or try to identify and eliminate .

In breeding has been pushed as being all evil and the root cause of pedigree dogs ill health - it probably is but its not because they are inbred its because of what they have selected for.

We live in exciting times with the ability to access greater knowledge and new science to enable us to score and tests and eliminate carriers etc and a time where in breeding could be used to ensure less dogs suffer as long as we make our choices with knowledge.

I made no blanket statement against in/line breeding as I'm getting different opinions for different sides and haven't had the time to read the huge amount of information carefully.

I am quite ready to say that close line breeding can unearth nasty recessive traits, and should not be undertaken by 'beginning' breeders who find it convenient to use a dog they have bred over his mother or half sister, even if he seems healthy and is a lovely dog.

The canine genome has around 3 billion base pairs. The general effect of inbreeding is to make an increasing number of those base pairs homozygous. Line- or inbreeding with selection may help in getting the 'baddies' to drop out of the target base pairs, leaving the DNA more homozygous for the desired state of the target allele. How many traits are you breeding for . . . I'd guess less than 500. What happens to the 3 billion minus 500 base pairs? They also become more homozygous. Eventually this will lead to problems.

I came across a table for pup survival rate vs COI. Unfortunately, the blogger didn't note his source. If you have better data, please post it. But until someone comes up with verified numbers, this is what I accept as a tentative hypothesis:

COI: survival rate

<0.19: 75%

0.25-0.67: 51%

>0.67: 25%

source: http://www.astraean....g-yourself.html

But no one is suggesting we all do this all of the time. its simply something that can be done sometimes . You cant go byrandom stats because they don't consider variables. and what if anything has been selected for.

I can tell you here in my yard there is no difference between litter sizes or survival rates whether I do a close breeding or other wise but one of the things I select for is fertility. My inbred dogs live up to 20 as well.

[Steve]

Sandgrubber - no one is saying that inbreeding doesn't carry risks and as usual when discussing genetics even the "experts" cant agree .The point is that if its used in dog breeding , selectively with knowledge and specific goals it can be a good thing and just because a dog is closely related to another dog shouldn't automatically discount it as a possible mating.

the fact of the matter is that we do inbreed - its how we got our breeds , how we got health issues in our breeds and if we are to maintain viability of our breeds it needs to be used as a tool sometimes to take us where we want to go -

to inbred animals which allow us to be able to predict their characteristics so we can place puppies in homes which are most suited to them and their traits and characteristics.

To date we have selected for the wrong reasons - how the dog looks and overlooked other things which we should have been more aware of. So if someone is now considering a close mating with specific goals and knowledge of the risks

it shouldn't be out of hand discounted simply because of how close it is.

The basic question should be what we are selecting for not whether they are closely related and we have to simply own up to the fact that purebred dogs are inbred - its what we do - and it is what we have always done - just as any other breeders does of any other purebred animal - because the alternative is a generic dogs with little or no predictability including no ability to know what to test for or try to identify and eliminate .

In breeding has been pushed as being all evil and the root cause of pedigree dogs ill health - it probably is but its not because they are inbred its because of what they have selected for.

We live in exciting times with the ability to access greater knowledge and new science to enable us to score and tests and eliminate carriers etc and a time where in breeding could be used to ensure less dogs suffer as long as we make our choices with knowledge.

I made no blanket statement against in/line breeding as I'm getting different opinions for different sides and haven't had the time to read the huge amount of information carefully.

I am quite ready to say that close line breeding can unearth nasty recessive traits, and should not be undertaken by 'beginning' breeders who find it convenient to use a dog they have bred over his mother or half sister, even if he seems healthy and is a lovely dog.

The canine genome has around 3 billion base pairs. The general effect of inbreeding is to make an increasing number of those base pairs homozygous. Line- or inbreeding with selection may help in getting the 'baddies' to drop out of the target base pairs, leaving the DNA more homozygous for the desired state of the target allele. How many traits are you breeding for . . . I'd guess less than 500. What happens to the 3 billion minus 500 base pairs? They also become more homozygous. Eventually this will lead to problems.

I came across a table for pup survival rate vs COI. Unfortunately, the blogger didn't note his source. If you have better data, please post it. But until someone comes up with verified numbers, this is what I accept as a tentative hypothesis:

COI: survival rate

<0.19: 75%

0.25-0.67: 51%

>0.67: 25%

source: http://www.astraean....g-yourself.html

But no one is suggesting we all do this all of the time. Its simply something that can be done sometimes . You cant go by random stats because they don't consider variables and what - if anything has been selected for.

I can tell you here in my yard there is no difference between litter sizes or survival rates whether I do a close breeding or other wise but one of the things I select for is fertility. My inbred dogs live up to 20 as well.

Ive known breeders who select for small litters and one of the things given as a hand out via the Cat society back when I was breeding cats was advice to selectively breed for small litters and cats which came in season less often.

Im not advocating that everyone should go nuts and inbred Im saying dont just discount it because it can be a good tool when breeding purebred animals.

[BJean]

What is your opinion on matings? What do you think is too close? I have half brother and sister which i would like to mate as i believe they would compliment each other well. They have both same sire but there dams are different but related, the dog dam is the bitches mother daughter. I am thinking it could be too close but would love to hear opinions on this topic

I think you should breed what you think will produce the best and the last thing I would do is ask for opinions here;

because basically what relevance does another breeder's opinion have on what you do.

Who cares :)

I really cant see how you expect you are going to get any meaningful advice, when all the advice is going to come from the perspective of their own burrow to push

and if they do not know your dogs or their lineage ...

their opinions are just guess work at best.

Do you need that?

I dont think you do hon :)

Go with your own instinct, it's the most objective and honest opinion you'll get.

[Aziah]

What is your opinion on matings? What do you think is too close? I have half brother and sister which i would like to mate as i believe they would compliment each other well. They have both same sire but there dams are different but related, the dog dam is the bitches mother daughter. I am thinking it could be too close but would love to hear opinions on this topic

I think you should breed what you think will produce the best and the last thing I would do is ask for opinions here;

because basically what relevance does another breeder's opinion have on what you do.

Who cares :)

I really cant see how you expect you are going to get any meaningful advice, when all the advice is going to come from the perspective of their own burrow to push

and if they do not know your dogs or their lineage ...

their opinions are just guess work at best.

Do you need that?

I dont think you do hon :)

Go with your own instinct, it's the most objective and honest opinion you'll get.

[Astese]

We breed Bull Terriers for some 31 years and only once did we try the half brother half sister mating. We had a very good bitch which was mated to a very very very good dog both by the same sire as her but from different dams. The litter produced six puppies two out of the six were exceptional the others were homed as pets. The two puppies went on the win specicality shows and BIS All Breeds. We knew the lines and did not double up on faults you can take the risk only if you know your lines throughly and know to expect from that line of dogs etc. The dog and bitch later produced good speciments of the breed and are now behind many show winning stock. It comes down to knowing your lines, taking a risk and being prepared for dissapointment.

[Bilbo Baggins]

We breed Bull Terriers for some 31 years and only once did we try the half brother half sister mating. We had a very good bitch which was mated to a very very very good dog both by the same sire as her but from different dams. The litter produced six puppies two out of the six were exceptional the others were homed as pets. The two puppies went on the win specicality shows and BIS All Breeds. We knew the lines and did not double up on faults you can take the risk only if you know your lines throughly and know to expect from that line of dogs etc. The dog and bitch later produced good speciments of the breed and are now behind many show winning stock. It comes down to knowing your lines, taking a risk and being prepared for dissapointment.

You could do an outcrossing and get the same result.

[sandgrubber]

You cant go by random stats because they don't consider variables and what - if anything has been selected for.

You can and should consider random stats because the set of base pairs you are selecting for is much smaller than the set of base pairs you aren't selecting for.

If a dog has the equivalent of the condition I have that yield a biological false positive to the Wasserman test (the old test for syphilis), apparently a recessive gene whose expression often causes problems in the immune system, you'd never know it. Or, say there are three different recessives, all of related to the development of the mouth, but you only know about one of them. In the process of breeding out the two you know, you may be increasing the probability of the other three. Eg, hypothetically, you may half the probability of undershot jaw at the cost of doubling the probabilities of missing teeth and the probability of cleft palate.

Very little of a dog's genetic code controls things like body dimensions and colour, that we select for. A large amount of genetic structure governs things like biochemistry (hence, potentially affecting things such as allergies, cancer, foetal development, hormonal imbalance, pancreatis, etc., sometimes in a polygenetic mode). Rare, random deleterious recessive mutations can hide for a long time before a double recessive will cause a mutation to be expressed. Probabilities for double recessive of a rare gene increase rapidly with inbreeding. You won't be aware of a doubling of probability if it means the incidence of a hereditary disease goes from 1% to 2%.

At least that's the way I understand the theory.