Inbreeding

[CaptainPanic]

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Moderator Note

eyesOpened,

This is an official warning. You are breaking forum rules with personal attacks, logical fallacies and off-topic posts.

We do not care about the discussion on the other forum. This is the Scienceforums.net, and we have our own forum rules. I suggest you read these rules, because you have broken them already too often in this thread.

I have seen personal attacks, logical fallacies and off topic posts. All of that stops now. As a start, I suggest you forget about the discussion on that other forum altogether. Any mention of it will be seen as off-topic and as a violation of our rules. Any mention of paganism will also be seen as off topic in this thread. If you wish to discuss paganism, you can do so in another thread, in our religion forum. The religion forum has its own set of additional rules.

You will either discuss the science of genetics, or you will not post at all in this thread. Our forum is not a place to finish a fight that you couldn't end somewhere else.

MattyG and everybody else, you too shall stop referring to that other forum, and in this thread to paganism.

Do not reply to this moderator note. If you have a problem with it, use the report button.

[eyesOpened]

Suit yourself.

[eyesOpened]

... inbreeding increases the similarity between individuals in a localized population

should an event arise that threatens the populations survival (a disease is a great example)

a population with a high level of inbreeding will lack the variability throughout the population

and will have a very high chance of dying out

 

(this is the main argument against inbreeding (lowering the gene pool) and its an argument from the point of population genetics, not focused on individuals or specific traits)...

I see your point: "its an argument from the point of population genetics, not focused on individuals or specific traits". From your explanation, does it follows that a population lacking variability would have "a very high chance" of universal immunity from "an event", while a population with variability would have a lower chance of universal immunity?

 

 

... at the end of the day its all luck of the draw (and depending on your genetics you may be better off screwing your siblings)

That's consistent with my current understanding.

 

 

im not an ethical person (some people have called me extremely pragmatic)

so ill state the practical point of view....

Thanks.

[MattyG]

I see your point: "its an argument from the point of population genetics, not focused on individuals or specific traits". From your explanation, does it follows that a population lacking variability would have "a very high chance" of universal immunity from "an event", while a population with variability would have a lower chance of universal immunity?

 

Inbreeding causes a "very high chance" of universal susceptibility to diseases. This is exactly what happened during the Irish potato famine. As I learned in my university biology class, nearly all the potato plants in Ireland were descended from a single specimen from the Americas. The plants were nearly genetically identical thanks to inbreeding. Then when the potato blight (Phytophthora infestans) hit Ireland, none of them had resistance because they lacked the genes that provided resistance, and could never gain them because they only inbred. This caused an enormous ecological disaster, not only killing the potatoes, but the people that depended on them. The idea of "universal immunity" is a joke. A species survives best when they have the greatest possible number of genes. Inbreeding narrows the gene pool significantly, leaving the population unable to deal with unforeseen disasters. Ok, maybe this inbred community will be "universally immune" to one disease, but the lack of variety is going to leave them unprepared for a million other diseases that want to fuck them up.

 

I don't understand why people feel the need to take natural selection into their own hands and breed some kind of uber-mensch. I think evolution's been doing a pretty good job on it's own. There's no such thing as "perfect genetics." Different genes are beneficial for different purposes. White skin is great for producing vitamin D in polar climates, but gives you cancer in equatorial areas. Increased intelligence is good if you're part of an advanced civilization, but a big brain's a waste if you don't have the caloric intake to support it. Nature has a way of weeding out things that are entirely useless. Have a varied gene pool, and your population can survive anything.

Edited September 11, 2012 by MattyG

[Phi for All]

Inbreeding causes a "very high chance" of universal susceptibility to diseases. This is exactly what happened during the Irish potato famine. As I learned in my university biology class, nearly all the potato plants in Ireland were descended from a single specimen from the Americas. The plants were nearly genetically identical thanks to inbreeding. Then when the potato blight (Phytophthora infestans) hit Ireland, none of them had resistance because they lacked the genes that provided resistance, and could never gain them because they only inbred. This caused an enormous ecological disaster, not only killing the potatoes, but the people that depended on them. The idea of "universal immunity" is a joke. A species survives best when they have the greatest possible number of genes. Inbreeding narrows the gene pool significantly, leaving the population unable to deal with unforeseen disasters. Ok, maybe this inbred community will be "universally immune" to one disease, but the lack of variety is going to leave them unprepared for a million other diseases that want to fuck them up.

Great point. The Cavendish banana, the most commonly sold banana in the world, lacks genetic diversity and is thus vulnerable to diseases like Panama disease. The whole strain could be wiped out and there really is nothing similar to replace it. The Gros Michel banana that people ate up until the 1960s was supposedly bigger and sweeter than the Cavendish, and it got wiped out by an earlier strain of Panama disease.

[eyesOpened]

... I don't understand why people feel the need to take natural selection into their own hands and breed some kind of uber-mensch....

I can't speak for them, but some of the proponents of forced-outbreeding (i.e., eugenics) may have a hidden agenda of trying to garner mainstream acceptance of their animal-f-cking ways. You know, "hey the reason I like f-cking animals (all animals, not just mammals) is to maximize the population's gene variability, uber-population, so we can avoid extinction."

 

... The idea of "universal immunity" is a joke....

It used to be said that the idea of a beneficial recessive trait was a joke, but sometimes people just talk instead of thinking.

 

Inbreeding narrows the gene pool significantly, leaving the population unable to deal with unforeseen disasters.

Sometimes, and sometimes narrowing the gene pool leaves the population more able to deal with "disasters".

 

A species survives best when they have the greatest possible number of genes.

Touting a university degree and calling your opponents Hitler is what it is, but it's not the same as supporting your assertions with evidence, and around here, people are said to be required to support their assertions with evidence.

Edited September 12, 2012 by eyesOpened

[MattyG]

I can't speak for them, but some of the propenents of forced-outbreeding (i.e., eugenics) may have a hidden agenda of trying to garner mainstream acceptance of their animal-f-cking ways. You know, "hey the reason I like f-cking animals (all animals, not just mammals) is to maximize the population's gene variability, uber-population, so we can avoid extinction."

 

Eugenics: eu·gen·ics   [yoo-jen-iks] noun ( used with a singular verb )

the study of or belief in the possibility of improving the qualities of the human species or a human population, especially by such means as discouraging reproduction by persons having genetic defects or presumed to have inheritable undesirable traits (negative eugenics) or encouraging reproduction by persons presumed to have inheritable desirable traits (positive eugenics).

 

No where does it say that eugenics focuses on either outbreeding, or animal-fucking as you claim. I know it's much easier to make an argument when you change the definitions of words, but I think bringing in animal-fucking was probably going too far. Eugenics generally focuses on inbreeding, whether within families or specific ethnic groups, from the belief that that specific group contains the best genes, while other groups should not be allowed to breed. Also, I'm concerned that you think that human beings can reproduce with animals. My university degree may not make me an expert, but I really think you should have a conversation with your local high-school biology teacher before trying to argue any further.

 

It used to be said that the idea of a beneficial recessive trait was a joke, but sometimes people just talk instead of thinking.

 

No one ever said that. They've just said that beneficial recessive traits will tend to become the norm, as negative dominant traits are weeded out more quickly.

 

 

Sometimes, and sometimes narrowing the gene pool leaves the population more able to deal with "disasters".

 

No, not really. Only the family of inbred hicks that just happens to have the one specific gene to deal with the one specific disaster. And the next catastrophe is going to wipe them the fuck out.

 

 

Touting a university degree and calling your opponents Hitler is what it is, but it's not the same as supporting your assertions with evidence, and around here, people are said to be required to support their assertions with evidence.

 

 

I don't ever remember using the word "Hitler," but I do remember listing various historical examples of inbreeding gone wrong, as well as some basic, high-school level thought experiments with basic biology, so there's that. And once again, my university degree by no means makes me an expert, but it's still better than not understanding elementary biology concepts.

[hypervalent_iodine]

!

Moderator Note

Please tone down the language and the snarky comments.

the argument that inbreeding causes birth defects is as far (as i know) a lot of hot air
there is plenty of evidence against it(just look at plants(self fertilization), plenty of examples of inbreeding in lab mice, animal breeders)

You've ignored the other half of this analogy. Very recently, I was reading a piece presented by J.B.S. Haldane in the 1935 Sir Halley Stewart lecture. Although it's old and although some of the science is outdated, it's quite an interesting read, and I think the way he relates this type of analogy to human eugenic policy to be quite good and much better than what I could write, so I'll quote it here. This also, I think, goes to answer some of the questions by eyesOpened.

First, I think, comes the false analogy with domestic animals. In domestic animals we select in the most rigid manner for desirable characters by castrating or killing a large majority of males, by only breeding from selected females, and, above all, by fixing such characters as we have got by fairly close inbreeding. There is no question that by inbreeding the large majority of characters in animals can be fixed so that they are manifested in all, or nearly all, of the progeny. But, in the course of inbreeding, a large number of abnormal types appear in early generations. In the case of animals the are destroyed. I think a policy of that kind, a eugenic policy involving inbreeding, might be quite suited to a society in which defective children were killed off. But rightly, as I think, our society takes a different view on human life, and unless we are to alter our ethical code radically we have to avoid inbreeding. We must realize that we cannot fix those characters which we regard as desirable. Therefore, although we could undoubtedly get rid of a certain number of defectives by sterilization, or by less drastic measures, we cannot hope to, and perhaps it is a very good thing that we cannot hope to, attain in man anything like the degree of fixity which is possible in domestic animals.

yes there are genetic defects tied to receive genes, also there are defects tied to dominant genes, co dominant genes, various allele combinations, lethal gene combinations and anything else you can think of
in a random mating you are less likely to get a rare trait expressed then you are with siblings, but at the end of the day its all luck of the draw (and depending on your genetics you may be better off screwing your siblings)
all the negative effects of incest have seen in a quick search resulted psychobabel, or geneologys of long dead kings/queens(which in my opinion is, for the most part, worthless as evidence of anything)

This is very much not true. Incest was fairly common practice in Europe the general population as late as last century (and is still common in other parts of the world) and there have been a number of diseases whose frequency is contributed to a great deal by the fact that the parents of affected persons were heterozygous first cousins, etc. It is certainly not limited to the royal family.

A quick search of my own yielded these:

http://jmg.highwire..../3/212.abstract
http://onlinelibrary...1171.x/abstract

You might also want to read this: http://en.wikipedia..../Founder_effect

[eyesOpened]

Outbreeding causes infertility: http://abcnews.go.com/Health/ReproductiveHealth/story?id=4258128&page=1

[Phi for All]

Outbreeding causes infertility: http://abcnews.go.co...=4258128&page=1

Incorrect. Breeding 15-17% less often ≠ infertility.

[eyesOpened]

Incorrect. Breeding 15-17% less often ≠ infertility.

Now we have to go back and correct all the claims that inbreeding "causes defects", since it doesn't 100% of the time.

[Phi for All]

Now we have to go back and correct all the claims that inbreeding "causes defects", since it doesn't 100% of the time.

No, we just have to look up the definition of infertility. I'll leave that up to your intellectual honesty. Especially since "causes defects" 100% of the time only appears in your post.

[LaurieAG]

Just realized I could add an example like Sickle Cell Anemia where a DomRec will prevent future disease.

You refer to the much higher percentage of the population who have sickle cell anaemia in areas of Africa susceptible to 'sleeping sickness' (Human African trypanosomiasis) caused by the Tsetse Fly. At university (in the 90's) this was described as a local example of continuing human evolution (survival of the fittest). Inbreeding between people with this disease would serve no purpose and give no extra benefit so it is not a good example.

Edited September 12, 2012 by LaurieAG

[MattyG]

You've ignored the other half of this analogy.

Also, ignoring the fact that a great number of plants and animals do suffer from frequent inbreeding. For example, the potatoes of the Irish potato famine, or purebred dogs that frequently display hip problems and the like.

 

 

Now we have to go back and correct all the claims that inbreeding "causes defects", since it doesn't 100% of the time.

 

No one has claimed that 100% of outbreeding results in beneficial traits, or that 100% of inbreeding results in negative traits. Inbreeding has a much higher likelihood of producing negative traits, with little to no higher probability of producing positive traits.

 

Outbreeding has been the norm for most animals for a good reason. Inbred populations have less variability in their gene pool. They are not properly equipped to deal with a wide variety of environmental factors. If inbreeding produced more beneficial traits in a species, it would be far more common. You're not just arguing against opinions, you're arguing against scientific and historical facts. Life on Earth, animal life in particular, has evolved a method of reproduction designed specifically to increase the variety of genetic diversity. The Westermark effect helps inspire us to have children that are genetically different from ourselves. It's the best way for us to survive as a species, and the best way to keep individuals alive and healthy.

 

You refer to the much higher percentage of the population who have sickle cell anaemia in areas of Africa susceptible to 'sleeping sickness' (Human African trypanosomiasis) caused by the Tsetse Fly. At university (in the 90's) this was described as a local example of continuing human evolution (survival of the fittest). Inbreeding between people with this disease would serve no purpose and give no extra benefit so it is not a good example.

 

Sorry, but I'm not sure I get what you're saying. I wasn't saying that inbreeding between people with the disease would help. I'm making an argument against inbreeding. If you're a carrier of the Sickle Cell gene, it's best for you to outbreed so you avoid giving your child another sickle cell gene from a closely related person.

[eyesOpened]

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Also, ignoring the fact that a great number of plants and animals do suffer from frequent inbreeding. For example, the potatoes of the Irish potato famine, or purebred dogs that frequently display hip problems and the like.

 

 

 

No one has claimed that 100% of outbreeding results in beneficial traits, or that 100% of inbreeding results in negative traits. Inbreeding has a much higher likelihood of producing negative traits, with little to no higher probability of producing positive traits.

 

Outbreeding has been the norm for most animals for a good reason. Inbred populations have less variability in their gene pool. They are not properly equipped to deal with a wide variety of environmental factors. If inbreeding produced more beneficial traits in a species, it would be far more common. You're not just arguing against opinions, you're arguing against scientific and historical facts. Life on Earth, animal life in particular, has evolved a method of reproduction designed specifically to increase the variety of genetic diversity. The Westermark effect helps inspire us to have children that are genetically different from ourselves. It's the best way for us to survive as a species, and the best way to keep individuals alive and healthy.

 

 

 

Sorry, but I'm not sure I get what you're saying. I wasn't saying that inbreeding between people with the disease would help. I'm making an argument against inbreeding. If you're a carrier of the Sickle Cell gene, it's best for you to outbreed so you avoid giving your child another sickle cell gene from a closely related person.

Unsupported opinions are a dime a dozen.

[MattyG]

Unsupported opinions are a dime a dozen.

 

 

Which of my "opinions" are unsupported? The ones I've supported with history? The ones I've supported with logical thought experiments requiring no more than a high school level of understanding of biology? The ones supported by genetic and social norms? The ones supported by scientific research (I know you love Wikipedia, so http://en.wikipedia.org/wiki/Pedigree_collapse http://en.wikipedia.org/wiki/Consanguinity as well as 48,800 scholarly articles found through a simple Google search http://scholar.google.com/scholar?q=Effects+of+human+inbreeding&hl=en&as_sdt=0&as_vis=1&oi=scholart&sa=X&ei=oCVQUIH6PO32igKSzYH4CQ&ved=0CBwQgQMwAA feel free to browse them at your leisure)?

 

So please let me know which claims I've made that lack support.

[eyesOpened]

So please let me know which claims I've made that lack support.

To start with, the proposition quoted in the first post in this thread: "Most of the odd things tied to recessive genes in humans are defects."

Edited September 12, 2012 by eyesOpened

[MattyG]

The proposition quoted in the first post in this thread, to start with.

 

Firstly, your assertion that my claims were "unsupported" was a response to a specific comment in which I made several claims about the biology of inbreeding. Not to "the first post in this thread." Which of those specific claims are unfounded?

 

Secondly, the first post in this thread was your own. While I would agree that most of your claims are unfounded or highly misconstrued, I find it unlikely that you're referring to your own claims. Therefore, I can only assume that you meant my first post to the forum, which was, in fact about the religious debate that brought you to this forum.

 

It's debatable whether or not that specific claim was unfounded since a link to the previous forum was posted for anyone to see, but I will agree that it was severely off topic. I've made my apologies to the moderators of this community since their warning was posted, and have since attempted to keep my posts in this thread to specifically scientific matters.

 

In conclusion, if you believe that any of my claims relating specifically to the science and/or history of inbreeding from a genetic standpoint are unsupported, please cite specific claims, and please try to keep the discussion on topic.

 

Edit: Sorry, you've edited your quote since I posted this. As to "Most of the odd things tied to recessive genes in humans are defects," I've never made that claim. You're the only one in this thread who's ever stated that. I've only said that recessive traits with a positive influence are going to tend to become the norm in a human population, because the negative dominant traits are going to be selected against naturally. I've also stated that the kinds of recessive traits that are likely to become manifest through inbreeding are going to be either negative or inconsequential, since those are the kind that are going to hide in a population's gene pool without presenting themselves as often (examples, the red-head gene as inconsequential or the genes for Cystic fibrosis as a negative). Please avoid putting words in my mouth in the future.

Edited September 12, 2012 by MattyG

[eyesOpened]

Firstly, your assertion that my claims were "unsupported" was a response to a specific comment in which I made several claims about the biology of inbreeding. Not to "the first post in this thread." Which of those specific claims are unfounded?

 

Secondly, the first post in this thread was your own. While I would agree that most of your claims are unfounded or highly misconstrued, I find it unlikely that you're referring to your own claims. Therefore, I can only assume that you meant my first post to the forum, which was, in fact about the religious debate that brought you to this forum.

 

It's debatable whether or not that specific claim was unfounded since a link to the previous forum was posted for anyone to see, but I will agree that it was severely off topic. I've made my apologies to the moderators of this community since their warning was posted, and have since attempted to keep my posts in this thread to specifically scientific matters.

 

In conclusion, if you believe that any of my claims relating specifically to the science and/or history of inbreeding from a genetic standpoint are unsupported, please cite specific claims, and please try to keep the discussion on topic.

 

Edit: Sorry, you've edited your quote since I posted this. As to "Most of the odd things tied to recessive genes in humans are defects," I've never made that claim. You're the only one in this thread who's ever stated that. I've only said that recessive traits with a positive influence are going to tend to become the norm in a human population, because the negative dominant traits are going to be selected against naturally. I've also stated that the kinds of recessive traits that are likely to become manifest through inbreeding are going to be either negative or inconsequential, since those are the kind that are going to hide in a population's gene pool without presenting themselves as often (examples, the red-head gene as inconsequential or the genes for Cystic fibrosis as a negative). Please avoid putting words in my mouth in the future.

So I was wrong to assume that anything you've said in this thread was relevant to the thread's first post.

[MattyG]

So I was wrong to assume that anything you've said in this thread was relevant to the thread's first post.

 

You were wrong to say that I made the claims in the first post. No one in this thread has made the claim that "Most of the odd things tied to recessive genes in humans are defects," including myself. If you want to argue with me or discredit my claims, do not put claims in my mouth in order to do it. I have made several posts relating to the science and history of inbreeding and its effects on human genetics. If you are going to attempt to discredit me, please at least cite things that I have actually said.

[CaptainPanic]

!

Moderator Note

eyesOpened,
You still continue your logical fallacies. You're putting words into people's mouths, you are twisting facts and you ignore valid arguments. In short, you are just not participating in this discussion properly. Your style of posting resembles trolling more than it resembles a scientific discussion.

We are a very patient bunch of mods here, but our patience is running thin. Consider this your last warning.

[eyesOpened]

Mod, the record shows your accusations are baseless, and that you're uneven in your application of the rules. You're not being patient, you're being a tool.

Edited September 12, 2012 by eyesOpened

[Phi for All]

This is very much not true. Incest was fairly common practice in Europe the general population as late as last century (and is still common in other parts of the world) and there have been a number of diseases whose frequency is contributed to a great deal by the fact that the parents of affected persons were heterozygous first cousins, etc. It is certainly not limited to the royal family.

Besides susceptibility to diseases, there have also been studies linking inbreeding to mental disorders such as retardation, low intelligence, unipolar and bipolar depression, and schizophrenia.

 

http://www.matthewck...lution_2006.pdf (7.4. The effect of inbreeding on mental disorders)

[MattyG]

Besides susceptibility to diseases, there have also been studies linking inbreeding to mental disorders such as retardation, low intelligence, unipolar and bipolar depression, and schizophrenia.

 

http://www.matthewck...lution_2006.pdf (7.4. The effect of inbreeding on mental disorders)

 

I plan on reading this article later when I have time to make some sense of it. Could you possibly summarize the findings? Is it suggested that these mental disorders (though I don't like to categorize "low intelligence" as a disorder) are essentially recessive traits that manifest more often through inbreeding, or that there are additional factors?

[offended]

This thread should be renamed "inflammatory and provocative hand-waiving to detract, just a version of the red-herring fallacy".

 

Most of the odd things tied to recessive genes in humans are defects.

What basis is there for this assertion?

Science.

Has this alleged "science" ever been published, and if so, where specifically can it be read?

Looks like it's never been published.