# Inbreeding



## PrimalUrges (Dec 10, 2008)

Am I right in thinking that some (unscrupulous) breeders often breed a brother and sister (or other relative) to get their desired morph? I have heard this from various sources, and to be honest I was quite shocked. 

I am new to breeding, but wouldn't this help explain why, for example caramel royal pythons often have kinked spines, or spiders have involuntry twitching? After all humans that have been inbred tend to either have sort of physical / mental abnormality from what I have read.

I would like to hear what others (including breeders) have to say about this from an ethical stand point. I for one will NEVER breed siblings together, and am still researching before I get started, I've got my eye on Super Dwarf Retics tho, they look fantastic!

Peace, Love and Unity!


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## MrMike (Jun 28, 2008)

I'm probbaly not the person to speak about it, but below is an excellent post about it

http://www.reptileforums.co.uk/lizards/174682-inbreeding-depression-facts.html


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## PrimalUrges (Dec 10, 2008)

Thanks mate, that was an intense read! I'm sticking to my guns, no inbreeding for me!


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## GlasgowGecko (Feb 23, 2008)

I see your general point, based on a human moral standing. But if we are to assume that inbreeding (in its simplest form) is the process of becoming homozygous recessive for any given gene. If you breed two non related phenotypically identical individuals together, you are effectively inbreeding at that and other non phenotypically expressed loci, which are capable of having deleterious mutations associated.

So where would we draw a line?

Andy


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## kirsten (Jan 13, 2008)

i personally will be line/inbreeding, but will be carefully monitoring the offsprings, and every now and again introducing new blood into the line. i think inbreeding can be taken to an extreem, and this i do disagree with, but carefully done and with great monitorying i don't see the problem. i'd also like to mention generally speaking im against inbreeding, but i think if done properly it can have rewarding results.


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## GlasgowGecko (Feb 23, 2008)

What I think people don't realize, is that you can become recessive homozygous at a deleterious position WITHOUT inbreeding, it is simply a risk you run. There is NO set number of generations you can inbreed for without negative effects. It doesn't work like that, it is impossible to predict what an individuals burden will be before breeding.
Another interesting point is that inbreeding depression will generally only manifest if the trait is under selection, so in essence, many mutations can build up in a population with no negative effects until something changes, and it becomes negative to have the trait.
The best example of this has been shown with naked mole rats. Their society is very similar to that of a communal insect. They have a single breeding pair, and inbreeding is rife. Over a large number of generations NO inbreeding depression could be found. Unfortunately a virus was introduced (accidentally) which spread through two populations, an inbred one, and a less inbred one. The result was that a large proportion of the inbred ones died, and significantly less of the less inbred population.

My point here, is that it is almost impossible to predict what the effects would be, and how they would manifest IF at all.

Andy


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## Ssthisto (Aug 31, 2006)

PrimalUrges said:


> I've got my eye on Super Dwarf Retics tho, they look fantastic!


Super Dwarf reticulated pythons come from isolated island populations.

One of the reasons they're so small is because those isolated island populations are prone to inbreeding (if you have to swim umpteen miles to get to an unrelated mate, you are going to be mating with your cousins or siblings!) and the small size trait has been positively selected for.

You can inbreed and select for BENEFICIAL traits too!


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## funky1 (Jun 18, 2008)

Ssthisto said:


> Super Dwarf reticulated pythons come from isolated island populations.
> 
> One of the reasons they're so small is because those isolated island populations are prone to inbreeding (if you have to swim umpteen miles to get to an unrelated mate, you are going to be mating with your cousins or siblings!) and the small size trait has been positively selected for.
> 
> You can inbreed and select for BENEFICIAL traits too!


 Totally agree! Inbreeding is seen from a human mortality stand point, and it just has no place in the natural world (human morality). Survival of the fittest. If an animal has to breed with a relative to pass on it`s genes then it will do - and they have done for hundreds of thousands of years without any intervention from man. And yes, inbreeding to a degree can have many, many benefits - it`s when you don`t cease the inbreeding once specific problems have been unearthed, that it becomes more a case of cruelty to satisfy our curiousity/lust for control.


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## Skyespirit86 (Feb 23, 2008)

Some fired up people may deem line breeding as simply 'inbreeding' and make it the same thing in their minds as what goes on with inbred people, and pedigree dogs but its really dependent on what animal you are talking about. All people are breeding with reptiles is colours and patterns for the most part. The majority are based on passing on dominant/recessive genes. Eg to make a spider royal you only have to breed a spider to any other royal (as far as I know) because it s adominant trait. When a recessive trait is first found, eg amelanism in corn snakes it is bred to a normal, and the babies will all be 'het' for it. They just received 50% genes from an unrelated snake. The het babies are then either bred to each other or to one of their parents so that more homozygous aimals will be produced. That is a line breeding, and once there are loads of snakes available that carry the amel gene, they can be outbred all over the place to produce hets each time receiving 50% genes from a new snake. 

Its not like with dog where there are fixed breeds, and their bloodline has to remain 'pure.' The closest we get is selectively bred morphs eg sunglows, candycanes and abbott's okeetees, but different people develop their own lines over time, and people often cross orange and red candycanes or breed a sunglow to a normal amel. The gene pool is not fixed. 

The physical shape of snakes or their behaviour is not deliberately changed either and as I said, the only mutant genes that are furthered deliberately are colour/pattern genes not genes for anything else. If you look at pedigree dogs they have all kinds of weird physical abnormalities which have become 'breed points' eg massive skin folds, ridgebacks (which is associated with dermoid sinus, a disease similar to spina bifida I think) etc etc. I think the closest we ave got is scaleless snakes, but these are rare. Generally speaking anything that becomes ill is omitted from being bred. I think breeders of reptiles are generally very responsible. Take the stargazing thing in corns, or the short tail gene. Both were deemed detrimental to the snake and the breeders made sure it was not knowingly bred on, unlike say, Cavalier King Charles Spaniels with syringomelia who loads of people breed and don't get tested because they want the money and the glamour. That's another difference- reptiles are not bred under a competetive system of showing or judging. Snakes can be bred to anything if you want, and aprt from when someone is intentionally seeking to create a new selectively bred morph variation between individuals is generally accepted, eg in anerys. Some are black, some are brown but noone culls the brown ones because they don't like them or make out they're not 'real' anerys or something because they don't fit some vague, snotty glammed-upped standard.

Anyways, sometimes when a new gene or set of genes coding for a certain colour/pattern is discovered it is unknowingly associated with other genes that code for something detrimental to health, possibly even making it completely incompatible with life, eg I think there is one of the dominant royal traits, might be a woma? that if you try and produce a homozygous one (a super) will not survive past hatching. There is something associated with that gene that when homozygous is fatal, but it doesn' mean that all colour/pattern mutations have weird things like this assocated with them. 

Spinning and kinking aren't caused by inbreeding. All spider royals and other moprhs made using spiders carry the 'spinning' trait, although some may not show it at all, others may be really bad. It does not outwardly appear to stress them, they are known for being great feeders and great breeders. Many people feel that it is unnaceptable to breed them. Others think its not that bad, doesn't really affect them, just means some act a bit kooky.Obviously now everyone has them and they are a stunning-looking mutation that seems a fundamental part of many breeding projects that people aren' going to give up. It might seem selfish but I do genuinely believe that is only because it does not appear to be too bad. If the snakes were in pain, totally uncoordinated, stressed, ill....I don't think they would be bred anymore. From what I have seen reptile breeders are good on this front.

The spinning seems intrinsically linked to the spider gene/s because I think some people have tried breeding it out but it doesn't work. As the OP above mentioned- the history of your super dwarf retic is not going to be free of anyinbreeding. Ifyou like any recessive traits and know your genetics you'll find its impossible to further a recessive trait without at least 1 line breeding to start with. Then if you wanted to make a combo in the future with another trait you'd have to do it again, and many people may begin breeding by using some line breedings so that they don't have to buy mates for all of them, of which there may be many, however where possible I know people do try and do that and get unrelated mates at that. Its very unlikely that a person who bought one of the offspring would then do a line breeding themselves, then the person after that do another one, for long enough for inbreedingdepression to take place. 

Example: All British pugs are descended from around 50 individuals. If you imported 50 amels, then only ever bred these homozygous amel corn snakes and their offspring to other homozygous amel corn snakes for 100 years you would probably get the same thing happening. If breeding a pug was as simple as just breeding a dog homozygous for a recessive gene for fair hair, and they were outbred even as little as every 10 generations you probably wouldn't have the health problems you have now with pedigree dogs.


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## GlasgowGecko (Feb 23, 2008)

Skyespirit86 said:


> Some fired up people may deem line breeding as simply 'inbreeding' and make it the same thing in their minds as what goes on with inbred people, and pedigree dogs but its really dependent on what animal you are talking about. All people are breeding with reptiles is colours and patterns for the most part. The majority are based on passing on dominant/recessive genes. Eg to make a spider royal you only have to breed a spider to any other royal (as far as I know) because it s adominant trait. When a recessive trait is first found, eg amelanism in corn snakes it is bred to a normal, and the babies will all be 'het' for it. They just received 50% genes from an unrelated snake. The het babies are then either bred to each other or to one of their parents so that more homozygous aimals will be produced. That is a line breeding, and once there are loads of snakes available that carry the amel gene, they can be outbred all over the place to produce hets each time receiving 50% genes from a new snake.
> 
> Its not like with dog where there are fixed breeds, and their bloodline has to remain 'pure.' The closest we get is selectively bred morphs eg sunglows, candycanes and abbott's okeetees, but different people develop their own lines over time, and people often cross orange and red candycanes or breed a sunglow to a normal amel. The gene pool is not fixed.
> 
> ...


This is a very interesting statement, I'm not sure its true thought. It is most likely the result of genetic fixation of a deleterious mutation (either dom OR recessive) that is linked to another loci responsible for the phenotypic changes in Spider royals. Genetic fixation CANNOT occur without inbreeding. The point here is that selection was bypassed by allowing initial individuals that showed the reduced fitness associated to this character to reproduce, thus it became fixed....

Andy


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## Skyespirit86 (Feb 23, 2008)

GlasgowGecko said:


> This is a very interesting statement, I'm not sure its true thought. It is most likely the result of genetic fixation of a deleterious mutation (either dom OR recessive) that is linked to another loci responsible for the phenotypic changes in Spider royals. Genetic fixation CANNOT occur without inbreeding. The point here is that selection was bypassed by allowing initial individuals that showed the reduced fitness associated to this character to reproduce, thus it became fixed....
> 
> Andy


 
Why can't it occur without inbreeding? If you are saying the spinning is assoiated with all spiders now because originally the ones that spinned weren't eliminated from breeding stock, then this could be rectified by breeding a spider to a normal, then some of them would inherit the dominant spider gene, some wouldn't, some would inherit the spinning gene, some wouldn't. We can't make a bad gene somehow stick to the one for the spider pattern, even if we inbreed. It happened naturally. Mutations are random. Sometimes the mutation involves just a few bits of DNA that code for a colour, other times they include a few more by chance that involve its development or behaviour or something. If you then only bred the ones that didn't spin it should be possible to get rid of it, but it doesn't seem it is. Spinning appears to have been around since the word go with spiders, and I don;'t think its something breeders made just by the original line breeding of it, how can that work?


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## GlasgowGecko (Feb 23, 2008)

Skyespirit86 said:


> Why can't it occur without inbreeding? *If you are saying the spinning is assoiated with all spiders now because originally the ones that spinned weren't eliminated from breeding stock, then this could be rectified by breeding a spider to a normal, then some of them would inherit the dominant spider gene,* some wouldn't, some would inherit the spinning gene, some wouldn't. We can't make a bad gene somehow stick to the one for the spider pattern, even if we inbreed. It happened naturally. Mutations are random. Sometimes the mutation involves just a few bits of DNA that code for a colour, other times they include a few more by chance that involve its development or behaviour or something. If you then only bred the ones that didn't spin it should be possible to get rid of it, but it doesn't seem it is. Spinning appears to have been around since the word go with spiders, and I don;'t think its something breeders made just by the original line breeding of it, how can that work?


This is also not necessarily true, it depends on the type of inheritance. Its a little complicated for here, but we could go into it further later if you wish. The truth is that no-one knowns where or how these things are happening, so its very difficult to say...

Andy


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## PrimalUrges (Dec 10, 2008)

Wow! thanks every one! Some really interesting posts! it seems that alot of people have strong views on this subject, which I totally respect, and yeah, on the whole I would agree that reptile breeders are doing a good job at producing happy healthy morphs.

As for SD retics, wouldn't this be natural selection (survival of the fittest), rather than breeding for a certain aesthetic trait? The fact that they are from an insular area does _suggest_ that inbreeding would occur, but does not guaruntee it. There is still that random factor which is removed when humans are involved in their procreation. 

It does seem to me that certain morphs are more prone to carrying defective traits, and it is down to the breeder to be responsible about how they are reproduced.


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## Ssthisto (Aug 31, 2006)

PrimalUrges said:


> As for SD retics, wouldn't this be natural selection (survival of the fittest), rather than breeding for a certain aesthetic trait? The fact that they are from an insular area does _suggest_ that inbreeding would occur, but does not guaruntee it.


It absolutely DOES guarantee it.

For example, the island of Kaloatoa (Kalatoa) - known for a specific race of very small dwarf reticulated pythons with a specific phenotype (they all look similar) - is eight miles long and five miles wide. VERY small. It's also seventy miles away from the nearest large island (Flores). Rather further than an animal could casually swim to breed. 

I would say that the size of the island plus the distance of that island from any sort of "mainland" (and I use the word "mainland" loosely to refer to "islands at least five times the size") that all of the reticulated pythons on that island (and indeed the other five small islands which are within two to ten miles) are very closely related indeed - and are breeding with their siblings, parents, cousins, uncles, aunts and other very close relations.

That's why Kaloatoa retics all look similar - because the limited number of available mates means that every animal is related AND that common genes will become even more common ("increasing homozygosity") in the overall population. If there's an animal of the opposite sex available to breed with on your island, you're unlikely to swim to another island to find an unrelated one.


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## GlasgowGecko (Feb 23, 2008)

Although there has been a lot of speculation about inbreeding avoidance mechanisms by the use of close sibling recognition, I'm yet to be convinced for reptiles (there is some good evidence for higher mammals). This aside there is a definite fitness trade off between NOT mating, because all individuals are related, and mating with individuals producing offspring with a lower relative fitness. Evolutionarily speaking, the later (mating with siblings) is better.

Andy


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## Skyespirit86 (Feb 23, 2008)

I would also like to question your use of the word 'unscrupulous' in your first post. I reckon just about every breeder has line bred at some point, or would do, even if they are a bit against it. It is not the same kind of extreme situation as you might find with the breeding of other animals and a you know is necessary at some point to further certain traits. I think it is offensive to call some very genuine and caring breeders unscrupulous because they do this.
I am an ethical person too, but I believe in animal welfare not animal rights, and it is very straining and hurtful sometimes to argue with people about topics such as this because they are trying to be somehow ethically more pure or superior. Implying that you don't care! It can just be that people like me or the breeders you are referring to have asked themselves this question ages ago and, and come to their own practical (and considerate) conclusion about what to do. But rather than just get all activist and shout 'ban line breeding', we think of ways in which we can actually apply it to reality. We care about our animals but know that all the emotional 'save animals' stuff is just a dream that makes people feel superior. Activists are often hypocritical along with other people in society who claim to love animals, and convince themselves they are like animal mother theresas. If you looks at the progress we have made with eliminating cruelty, or eliminating diseases from pedigree dogs you'll realise this is just a great big lie. Reptile breeders from what I can see often take pride in having good knowledge and make more efforts than breeders of just about anything else to be responsible and professional. Anyone can sit and weep when watching animal hospital on tv or when reading something on the Peta website, but whether they actually do anything to help this world or actualy understand the subject they are getting all emotional about is another story. Try and look at yourself andask how ethical you really are without slyly covering over the bits you don't like in the back of your mind...then you'll get where I am talking from now.


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## PrimalUrges (Dec 10, 2008)

Skyespirit86 said:


> I would also like to question your use of the word 'unscrupulous' in your first post. I reckon just about every breeder has line bred at some point, or would do, even if they are a bit against it. It is not the same kind of extreme situation as you might find with the breeding of other animals and a you know is necessary at some point to further certain traits. I think it is offensive to call some very genuine and caring breeders unscrupulous because they do this.
> I am an ethical person too, but I believe in animal welfare not animal rights, and it is very straining and hurtful sometimes to argue with people about topics such as this because they are trying to be somehow ethically more pure or superior. Implying that you don't care! It can just be that people like me or the breeders you are referring to have asked themselves this question ages ago and, and come to their own practical (and considerate) conclusion about what to do. But rather than just get all activist and shout 'ban line breeding', we think of ways in which we can actually apply it to reality. We care about our animals but know that all the emotional 'save animals' stuff is just a dream that makes people feel superior. Activists are often hypocritical along with other people in society who claim to love animals, and convince themselves they are like animal mother theresas. If you looks at the progress we have made with eliminating cruelty, or eliminating diseases from pedigree dogs you'll realise this is just a great big lie. Reptile breeders from what I can see often take pride in having good knowledge and make more efforts than breeders of just about anything else to be responsible and professional. Anyone can sit and weep when watching animal hospital on tv or when reading something on the Peta website, but whether they actually do anything to help this world or actualy understand the subject they are getting all emotional about is another story. Try and look at yourself andask how ethical you really are without slyly covering over the bits you don't like in the back of your mind...then you'll get where I am talking from now.


OK fair enough, I apologise for the use of the word 'unscrupulous' it was used a little prematurely, and I certainly don't think that all or most breeders are unscrupulous (I wouldn't have bought their livestock otherwise!). I wanted to find out what the general ethical standpoint was regarding INBREEDING, because it does seem to me that there is an element of risk when doing this.

Since starting this thread (which is part of my research into doing my own breeding project) I have learned alot more about the results of inbreeding, and also line breeding, and I think a distinction should be drawn between the two. I am not, to quote you "get(ting) all activist and shout(ing) 'ban line breeding'" at all, you are putting words in my mouth. I was in no way trying to make myself feel superior to people, or take the moral high ground, I am merely trying to find out all of the facts before I get involved myself. Is that not an ethical, and responsible approach to breeding?

Just because I disagree with direct pairings eg brother/sister, mother/son does not mean that I am an activist, or 'animal mother theresa' I am entitled to my own informed opinion, and I will stick by it. I am however devoted to the animals that I do keep, and do everything in my power to make sure they are happy healthy creatures.


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## Ssthisto (Aug 31, 2006)

PrimalUrges said:


> I am however devoted to the animals that I do keep, and do everything in my power to make sure they are happy healthy creatures.


What if breeding siblings - or parent to child - was the best way to obtain happy healthy animals (by selecting for good feeding, good breeding, good doers who produce healthy fertile clutches with limited to no non-feeders) because you're selecting hard for good traits OTHER than colour?


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## PrimalUrges (Dec 10, 2008)

And this can only be achieved by inbreeding?


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## GlasgowGecko (Feb 23, 2008)

I really question those who flat out disagree with inbreeding, I honestly think that it just a case of either poor understanding of the facts, or misunderstanding (this isn't aimed at you PrimalUrges, its a generalisation). I can think of as many scientific positives for inbreeding as I can think of scientific negatives. 

Andy


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## chrisss_proctor (Aug 15, 2007)

I'm surprised no-one has put up a fact about human inbreeding. The chances of a child born to a brother and sister is 97% that the child will be perfectly normal. Don't forget that there are negative affects in two completely unrelated people having a child such as diseases, physical deformaties and mental health issues etc. Surely it is more of a social taboo than something that is physically or naturally 'wrong'?

This is unless you believe that God made the world in which case we are all inbred as we all originated from Adam and Eve! - Just to lighten the mood. :2thumb:


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## paulh (Sep 19, 2007)

Here's a bit about inbreeding that my father wrote a while back. He was a pro geneticist.

INBREEDING—HORRORS!?

Self-fertilization is the “closest” inbreeding. Mendel’s peas normally do it. Without
crossing, selfing for about 7 generations produces pure lines completely homozygous and
free of lethal and seriously detrimental genes. Like clones they are constant. Generally we
like reliability, despite monotony.

But most of our domestic crop and animal species are less inclined to pure-breed.
Maize pollen is normally wind-blown. Enforced self-fertilization of such plants produces
varied progeny because of segregation and recombination from heterozygous loci.
Statistically this is termed inbreeding depression, but pure lines can be produced—reliable
but commonly “inferior”. Crossing different pure lines produces uniform F1, generally
“superior” to the parents. The program of crossing may be extended—3-way, 4-way, etc. A
second cycle of selfing from such crossbreds may produce improved pure lines.

Brother-sister mating is the closest inbreeding for most animals. Pure lines may be
produced by long-continued sibling mating—again reliable, but expensive and often
“inferior” in some respect.

Cousin matings and parent-offspring matings are considered fairly-“close”
inbreeding, and with selection may gradually produce fairly pure lines—again reliable, and
possibly not “inferior”.

So why is inbreeding usually considered “bad”? Production of “defective”, lethal, or
otherwise undesirable progeny obviously seems best avoided. But how else can recessive
lethals and detrimental genes be exposed for elimination in an otherwise desirable stock?

Close inbreeding when the parents are mutually heterozygous for many (say 10)
deleterious genes may result in practically unavoidable homozygosity for one or more in the
progeny. That is scary. With “mild” inbreeding the parents are unlikely to have many
heterozygous deleterious genes in common so the results are less drastic. So with domestic
animals a happy medium seems the solution. How about pretzel breeding—in, out, around,
and back? The recipe is flexible.


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## jbaines (Sep 3, 2008)

paulh said:


> *Self-fertilization* is the “closest” inbreeding. *Mendel’s peas normally do it*. Without
> crossing, selfing for about 7 generations produces pure lines completely homozygous and
> free of lethal and seriously detrimental genes. Like clones they are constant. Generally we
> like reliability, despite monotony.


Ive just had a lecture on mendel and his peas. The pea plant doesnt self-polonate, it cross polonates. In fact he threw 8 years worth of reasarch aside when he tried to copy his experiment on other plants and they all came out identical (they were self-polonators, hence produced clones of themselves). Not realising this he thought all his research must be wrong because.
also people seem to be talking about 'homozygous recessive' as though its a bad thing, its only a bad thing if it happens to be an alliel that causes problems, such as cystic fibrosis. Other forms of homozygous recessive genes are those for blue eyes. Nowt wrong with blue eyes


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## GlasgowGecko (Feb 23, 2008)

jbaines said:


> Ive just had a lecture on mendel and his peas. The pea plant doesnt self-polonate, it cross polonates. In fact he threw 8 years worth of reasarch aside when he tried to copy his experiment on other plants and they all came out identical (they were self-polonators, hence produced clones of themselves). Not realising this he thought all his research must be wrong because.
> also people seem to be talking about 'homozygous recessive' as though its a bad thing, its only a bad thing if it happens to be an alliel that causes problems, such as cystic fibrosis. Other forms of homozygous recessive genes are those for blue eyes. Nowt wrong with blue eyes


Although this is technically true, plants in the family Fabaceae show the gametophytic self-incompatibility system which effectively prevents self polination (both from self, and from others with the same S-allele expressed), there is massive amounts of evidence for SI system breakdown, and there are evolutionary advantages for this, See bakers law, and reproductive assurance etc...

Evidence for inbreeding depression is actually difficult to find in natural populations of any species, and there are huge amounts of studies that have failed to observe it. The reason is that purging happens very early on in the populations history, and due to population size, inbreeding can then continue with no ill effects. One important thing to remember is that purging can only remove deleterious alleles that are under selection, so a change in environment in many of these cases may throw up reduced fitness.

What is also important to note, is that the effects of out-breeding depression can be just as severe as those of inbreeding, on small inbred populations.

Andy


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## jbaines (Sep 3, 2008)

GlasgowGecko said:


> Although this is technically true, plants in the family Fabaceae show the gametophytic self-incompatibility system which effectively prevents self polination (both from self, and from others with the same S-allele expressed), there is massive amounts of evidence for SI system breakdown, and there are evolutionary advantages for this, See bakers law, and reproductive assurance etc...
> 
> Evidence for inbreeding depression is actually difficult to find in natural populations of any species, and there are huge amounts of studies that have failed to observe it. The reason is that purging happens very early on in the populations history, and due to population size, inbreeding can then continue with no ill effects. One important thing to remember is that purging can only remove deleterious alleles that are under selection, so a change in environment in many of these cases may throw up reduced fitness.
> 
> ...


Any chance you could break that down a little please? Its an interesting topic but youve gone over my education and I cant understand most of that.
cheers.


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## kirsten (Jan 13, 2008)

Skyespirit86 said:


> I would also like to question your use of the word 'unscrupulous' in your first post. I reckon just about every breeder has line bred at some point, or would do, even if they are a bit against it. It is not the same kind of extreme situation as you might find with the breeding of other animals and a you know is necessary at some point to further certain traits. I think it is offensive to call some very genuine and caring breeders unscrupulous because they do this.
> I am an ethical person too, but I believe in animal welfare not animal rights, and it is very straining and hurtful sometimes to argue with people about topics such as this because they are trying to be somehow ethically more pure or superior. Implying that you don't care! It can just be that people like me or the breeders you are referring to have asked themselves this question ages ago and, and come to their own practical (and considerate) conclusion about what to do. But rather than just get all activist and shout 'ban line breeding', we think of ways in which we can actually apply it to reality. We care about our animals but know that all the emotional 'save animals' stuff is just a dream that makes people feel superior. Activists are often hypocritical along with other people in society who claim to love animals, and convince themselves they are like animal mother theresas. If you looks at the progress we have made with eliminating cruelty, or eliminating diseases from pedigree dogs you'll realise this is just a great big lie. Reptile breeders from what I can see often take pride in having good knowledge and make more efforts than breeders of just about anything else to be responsible and professional. Anyone can sit and weep when watching animal hospital on tv or when reading something on the Peta website, but whether they actually do anything to help this world or actualy understand the subject they are getting all emotional about is another story. Try and look at yourself andask how ethical you really are without slyly covering over the bits you don't like in the back of your mind...then you'll get where I am talking from now.


i totally agree (i appologise if this topic has changed slightly, coz i haven't read the whole thread) i am completely against the extreme pedigree dog breeding and some of the practicses that have come about with it, kulling pups that do not conform just as they are born, and such like (thankfully it looks like this practice is just about to die out, with all the stuff going on with crufts). But... i will be linebreeding, and yes this is different that just plain inbreeding, and i will be doing this carefully, not inscupulously.


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## GlasgowGecko (Feb 23, 2008)

jbaines said:


> Any chance you could break that down a little please? Its an interesting topic but youve gone over my education and I cant understand most of that.
> cheers.


I have to admit that self-incompatibility in plants is VERY complicated. Before I got my P.hD I knew nothing about them at all... so it was a steep learning curve.

The important point to take away is that it is a self recognition system which prevent pollen tube growth. It is tightly controlled by a number of genes. Mutations in these genes (or in further down stream processes) can cause a loss in function (just like with any gene). Mutation should be very unlikely as these genes are under tight selection, but it is seen frequently. This undoubtedly has some benefits, for example small founder populations (even a single individual) are able to survive and propagate a new population etc...

Andy


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## Lucifus (Aug 30, 2007)

All i know about is Human inbreeding and theirs a fairly large risk of psychological problems and some defects. 

The area i live in now is enclosed, not many people marry outside of the local area and as a result their hasn't been any diversity in the gene pool. Its bene like this for hundreds of years, its so bad if you plotted a chart you would find out that someone is related to someone here. Theirs a big paranoia that people "dont leave the valleys" and the transport system is devised to be difficult to even get to the major city thats 30 mins away by car. Everyone down here looks like each other to some extent. Big ears/noses and age very quickly let alone the mental defects. 

Inbreeding is unlikely to have huge problems within two generations however every gene pool needs "new blood" at some point or things start going horribly horribly wrong.


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## jbaines (Sep 3, 2008)

GlasgowGecko said:


> I have to admit that self-incompatibility in plants is VERY complicated. Before I got my P.hD I knew nothing about them at all... so it was a steep learning curve.
> 
> The important point to take away is that it is a self recognition system which prevent pollen tube growth. It is tightly controlled by a number of genes. Mutations in these genes (or in further down stream processes) can cause a loss in function (just like with any gene). Mutation should be very unlikely as these genes are under tight selection, but it is seen frequently. This undoubtedly has some benefits, for example small founder populations (even a single individual) are able to survive and propagate a new population etc...
> 
> Andy


Cheers Andy, that makes more sense, dont think im ready to take the exam yeth though, lol.


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## jbaines (Sep 3, 2008)

Lucifus said:


> All i know about is Human inbreeding and theirs a fairly large risk of psychological problems and some defects.
> 
> The area i live in now is enclosed, not many people marry outside of the local area and as a result their hasn't been any diversity in the gene pool. Its bene like this for hundreds of years, its so bad if you plotted a chart you would find out that someone is related to someone here. Theirs a big paranoia that people "dont leave the valleys" and the transport system is devised to be difficult to even get to the major city thats 30 mins away by car. Everyone down here looks like each other to some extent. Big ears/noses and age very quickly let alone the mental defects.
> 
> Inbreeding is unlikely to have huge problems within two generations however every gene pool needs "new blood" at some point or things start going horribly horribly wrong.


Hope none of your neighbours are on here mate, lol.

It can work both ways like someone already said. In the european decended orthodox jewish community in the uk they havelik a 1:500 chance of being born with gaucher disease compaired to 1:100,000 in the rest of the population. This is due to the redtricted gene poll as they tend to marry other orthodox jews. Americans however (I cant remember which disease or the figures but its just as striking) have a greatly increased chance of being born with another genetic disease, this is because they are a huge melting pot of immigrants (im not being right wing, everyone there except the native americans are immigrants, and even they were at some point in history. Sorry any mormons out there) so at some point people brought this with them. So you cant win basically.


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## Ssthisto (Aug 31, 2006)

Lucifus said:


> All i know about is Human inbreeding and theirs a fairly large risk of psychological problems and some defects.


Although, to be fair, if you did a survey of ALL the people who show psychological or physical defects (especially major ones) you'd find that the vast majority of them are from "unrelated" pairings!

For example, my dad is colourblind. My mother is not colourblind. I am not colourblind. But my younger brother is ALSO colourblind - and the particular type of colourblindness is carried on the X chromosome, NEVER the Y. Which means my brother got the colourblindness trait from my mum, not from my dad... and that I'm 100% het for colourblind (which means any son I ever had would have a 50% chance of being colour blind himself). 

And my parents aren't related any closer than 16 generations back (and possibly further - it's just that we've researched our family tree that far back!)


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## GlasgowGecko (Feb 23, 2008)

Lucifus said:


> Inbreeding is unlikely to have huge problems within two generations however *every gene pool needs "new blood" at some point* or things start going horribly horribly wrong.


I agree with all your point except this. There are some well documented examples of the opposite being true. For example, Cheetahs, have a very high level of inbreeding due to population size and behavior. This means they have become very specialized. Introducing "new blood" if it existed could in fact cause out breeding depression, which show very similar effects and would be very destructive. This is not an isolated example, but the general point is that if a species or population survives a bout of inbreeding (either purging or genetic fixation occurring) then no further inbreeding depression will occur. This point is important. If new heterozygotes are then introduced, marked depression in fitness is seen.

Andy


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## Lucifus (Aug 30, 2007)

Ssthisto said:


> Although, to be fair, if you did a survey of ALL the people who show psychological or physical defects (especially major ones) you'd find that the vast majority of them are from "unrelated" pairings!


Yes but not being inbred doesn't exclude you from defects. The proportion of inbred in the UK is quite low so you have to adjust for statistical imbalances.



GlasgowGecko said:


> I agree with all your point except this. There are some well documented examples of the opposite being true. For example, Cheetahs, have a very high level of inbreeding due to population size and behavior. This means they have become very specialized. Introducing "new blood" if it existed could in fact cause out breeding depression, which show very similar effects and would be very destructive. This is not an isolated example, but the general point is that if a species or population survives a bout of inbreeding (either purging or genetic fixation occurring) then no further inbreeding depression will occur. This point is important. If new heterozygotes are then introduced, marked depression in fitness is seen.
> 
> Andy


Thats an interesting point but im guessing its a rare example whereby they have evolved to inbreed? May look into that.


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## Ssthisto (Aug 31, 2006)

Lucifus said:


> Thats an interesting point but im guessing its a rare example whereby they have evolved to inbreed? May look into that.


Actually, many species have restricted breeding ranges (imagine, say, a group of rosy boas in a canyon) and would be of necessity inbred to some extent.

The reason you get genetically "healthy" inbred animals in the wild is because they are HARSHLY selected against - anything that isn't fit to survive and breed successfully just plain doesn't.


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## Joe1507 (Aug 11, 2008)

Incest.


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## GlasgowGecko (Feb 23, 2008)

Lucifus said:


> Thats an interesting point but im guessing its a rare example whereby they have evolved to inbreed? May look into that.


Not really that rare at all. It's perhaps best to look at inbreeding on a population level, and in doing this it becomes clear that inbreeding is very common, in the vast majority of species.

Andy


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## Lucifus (Aug 30, 2007)

GlasgowGecko said:


> Not really that rare at all. It's perhaps best to look at inbreeding on a population level, and in doing this it becomes clear that inbreeding is very common, in the vast majority of species.
> 
> Andy


Just did some more research and found suprisingly that inbreeding in humans is more common than i thought. 

"
Inbreeding is practiced due to various reasons. While Hindus and Muslims of India and Africa practice inbreeding for cultural and religious reasons, Amish, Mennomites and Hutterites practiced it because they were isolated. In Dammam, Saudi Arabia, the inbreeding coefficient is high (0.0312). This high rate of inbreeding is due to beliefs, culture, and to keep property within the family. 



Another reason responsible for inbreeding is socioeconomic status—the rich wanting to marry only the rich to maintain their status and thus looking in their own families for partners and poor only being able to afford a marriage among themselves. Interestingly, some royal societies have also been known to practice inbreeding to protect royal blood lines. For example, the English Royal family has had many hemophiliac members due to inbreeding. " 

Studies i read however did show a decrease of risk of cancer, however the morbidity for inbred children was quite high, the children only learned to walk and talk at the age of five, well behind their non-inbred counterparts and fertility rates were low. Some negative traits that put them at high risk for certain conditions were also removed.



Joe1507 said:


> Incest.


Very helpful...


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