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Selfish Gene Theory
#1
Selfish Gene Theory
I'm currently reading through Richard Dawkins' The Selfish Gene and I've been trying to locate a good doc or YouTube video to help me visually understand some of the concepts he expresses... And I can't really find anything besides lectures. Does anyone know of some vids I can watch? Please post them if you do!
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#2
RE: Selfish Gene Theory
What specific concepts are you referring to?

I've read select excerpts from that book as assigned reading for some of my evolution courses at uni and I've read Dawkins' Ancestor's Tale, I am quite well-versed with his concept of evolution (also have read other books/textbooks on the subject and very much prefer Dawkins'). If you need some help we could have a discussion, Big Grin I love talking about these things but no one else really does, lol.
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#3
RE: Selfish Gene Theory
Sure! One thing that throws me off in trying to imagine the actual utility of the gene is his personification and metaphors comparing them to conscious agents. In what way exactly are genes "alive" in the survival machine? Should I imagine it in the way that viruses or bacterias are? I recently read an Ernst Mayr selection and he was no fan of the selfish gene theory because in his opinion natural selection could only pressure individual phenotypes, rather than the (millions? billions?) of genes within the individual. Can you expound on this process of gene selection?
He who loves God cannot endeavour that God should love him in return - Baruch Spinoza
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#4
RE: Selfish Gene Theory
(February 1, 2014 at 2:44 pm)Pickup_shonuff Wrote: Sure! One thing that throws me off in trying to imagine the actual utility of the gene is his personification and metaphors comparing them to conscious agents. In what way exactly are genes "alive" in the survival machine? Should I imagine it in the way that viruses or bacterias are? I recently read an Ernst Mayr selection and he was no fan of the selfish gene theory because in his opinion natural selection could only pressure individual phenotypes, rather than the (millions? billions?) of genes within the individual. Can you expound on this process of gene selection?

Oh ok. No, genes aren't conscious. I'm not sure which specific part of the book you're referring to, but genes are alive because they still call the shots. Their job isn't done when the machine is built, they are highly regulated and respond to stimuli, except there is a time delay in the response, which is why the machine has a certain amount of autonomy to ensure survival.

To understand the selfish gene theory, you must first understand that genes are possibly immortal. They can be copied for an eternity. But machines are mortal and die off, most likely never to be replicated again. So the ultimate goal of evolution is the survival of the genes, not the survival of machines. The traditional view used to be more egocentric and view the genes as servants of the machine. The selfish gene theory flips that around.

That's why selection is ultimately gene selection and not really phenotypic selection. Because phenotypes only get passed on if the genes for it are there. If the genes aren't there, the phenotype dies off. You cannot select one without selecting the other. But because genes are more permanent in the evolutionary timescale, it is the one that is ultimately selected. You can have genes in you that is no longer expressing itself but piggybacking on the active genes. These can still pull tricks that ensure their survival without affecting phenotype. Such as being close (in terms of placement on the actual chromosome) to a very important gene. So every time the very important gene gets passed on, this useless gene gets to survive another generation of machines.

Edit: Oh and remember that the measure of fitness in evolution isn't how well you survive but how well you reproduce. So the machine is selected to propagate the genes and the genes are not selected to help the survival of the machine after the machine is past reproductive age. In fact, a theory for aging and senescence is that we have a lot of beneficial genes that turn bad after a certain age, but they get passed on because we reproduce when we're younger. So genes do not serve the machine, they only help us to help themselves.
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#5
RE: Selfish Gene Theory
(February 1, 2014 at 3:05 pm)pineapplebunnybounce Wrote:
(February 1, 2014 at 2:44 pm)Pickup_shonuff Wrote: Sure! One thing that throws me off in trying to imagine the actual utility of the gene is his personification and metaphors comparing them to conscious agents. In what way exactly are genes "alive" in the survival machine? Should I imagine it in the way that viruses or bacterias are? I recently read an Ernst Mayr selection and he was no fan of the selfish gene theory because in his opinion natural selection could only pressure individual phenotypes, rather than the (millions? billions?) of genes within the individual. Can you expound on this process of gene selection?

Oh ok. No, genes aren't conscious. I'm not sure which specific part of the book you're referring to, but genes are alive because they still call the shots. Their job isn't done when the machine is built, they are highly regulated and respond to stimuli, except there is a time delay in the response, which is why the machine has a certain amount of autonomy to ensure survival.

To understand the selfish gene theory, you must first understand that genes are possibly immortal. They can be copied for an eternity. But machines are mortal and die off, most likely never to be replicated again. So the ultimate goal of evolution is the survival of the genes, not the survival of machines. The traditional view used to be more egocentric and view the genes as servants of the machine. The selfish gene theory flips that around.

That's why selection is ultimately gene selection and not really phenotypic selection. Because phenotypes only get passed on if the genes for it are there. If the genes aren't there, the phenotype dies off. You cannot select one without selecting the other. But because genes are more permanent in the evolutionary timescale, it is the one that is ultimately selected. You can have genes in you that is no longer expressing itself but piggybacking on the active genes. These can still pull tricks that ensure their survival without affecting phenotype. Such as being close (in terms of placement on the actual chromosome) to a very important gene. So every time the very important gene gets passed on, this useless gene gets to survive another generation of machines.

Edit: Oh and remember that the measure of fitness in evolution isn't how well you survive but how well you reproduce. So the machine is selected to propagate the genes and the genes are not selected to help the survival of the machine after the machine is past reproductive age. In fact, a theory for aging and senescence is that we have a lot of beneficial genes that turn bad after a certain age, but they get passed on because we reproduce when we're younger. So genes do not serve the machine, they only help us to help themselves.

Thanks for the explanation! I'm really benefiting from this. I have some further points of confusion, however, that perhaps you can clarify. For one, the reason I find his personification of genes a bit difficult to understand is that I'm not quite sure what to make of the microscopic equivalent of "purpose" or their "propensity to propagate," or as you describe it, "still call the shots." This appears all to obvious in the case of brains, where we now recognize specific regions that stimuli "pleasure" or "reward," for example, but what exactly determines a gene's "will to power" or foresight to altruistically sacrifice itself for the betterment of its kin?

Secondly, I'm baffled as to why, if "the ultimate goal of evolution is the survival of the genes, not the survival of machines," genes would ever evolve to "progenate" only 50 percent of themselves as in the case of sexual selection. Why does anything reproduce rather simply replicate? And also, my understanding of Darwinism is that its appeal, the reason why it is such a revolutionary and controversial idea, is that it explains evolution in the absence of "goals" or "teleology," by natural selection. But the selfish gene theory seems to be somewhat at odds with this orthodoxy if we start introducing "ultimate goals," and is this not the case when we speak of genes as "pulling tricks" to ensure their survival? On the other hand, I suppose I could speak of an unintelligent organism, and it seems to be a similar situation, so if we understand what benefit a simple organism "feels?" at helping itself, I suppose the same principle can apply to the DNA of genes-- by the way, is the selfish gene reducible to selfish DNA?

Like I said, the metaphors are kind of tripping me up. I'm trying to understand the philosophy of the selfish gene theory and how it corresponds to the unguided, unintelligent process of natural selection, which obviously Dawkins adheres to (maybe he'll pull it all together in the final chapters?)
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#6
RE: Selfish Gene Theory
Hm, ok I see what you're struggling with. I won't be responding parts by parts because I think I may be able to explain it with more context in another order.

First mistake is that genes are not sets of DNA. A set of DNA is made up of multiple genes. So in sexual selection, genes still get passed on, entire ones, they don't split up and only pass on 50%. The benefit of sexual selection is diversity. The potato famine happened because all of the potatoes had the same DNA makeup and all got infected (or what do you call it). That wouldn't have happened if they did not propagate through cloning (exact replicates as offsprings). So if a huge bunch of machines can die, the genes within them get reduced chances of being copied pass this generation.

Now, the next thing would be to understand that although genes are just genes and not a set of DNA, many of them would not survive (get passed on indefinitely) without the "help" of other genes. A single gene cannot make a machine. But a machine is necessary to protect and replicate the genes. Everything that you see at the phenotypic level was brought about by genes. Once upon a time, you were just a single cell, the genes (those in your DNA) coded for proteins and these proteins affected change that made that cell into a baby and then into an adult. But if you do not have the gene for hair, you wouldn't have hair. Even though it's part of the machine now, it is the result of a gene. That is the "foresight" that genes have. If you have a gene that allows you to feel pain, you will survive better than a machine without that gene. A lot of things are essential to your survival and all those, no matter how complicated, could not have happened if the gene for it wasn't there. Makes sense?

When I said genes still call the shots, I meant a lot of what you do, in fact maybe even all of it, you're only able to do because of your genes. If you did not have the genes for a human brain, you wouldn't be able to make decisions like you do now. And also, genes are constantly being translated into proteins that keep you alive, the process is not rigid and still responds to stimuli. So it does maintain a level of control that you do not have (you cannot will cancer away just because you want to). If you have "good genes" it means your set of genes makes a machine that is good at survival and reproduction.

Although it isn't really "foresight". Imagine asking a billion people to take a test without telling them what they'll be tested on. And then tell them if they fail they'll die. That's like natural selection. No gene can see the future and be like, right, I better modify myself a little bit and tell my neighbours to change A, B, C and D to prepare for the ice age. It's basically a lot of genes that make a lot of machines and some machines don't do well for whatever reason. So in hindsight, it seems as if the genes really have some sort of foresight, but of course they don't. So when I said a gene is pulling tricks, it really isn't. It was just "lucky" (by chance), to land beside a useful gene and therefore gets passed on when that useful gene is passed on.

And I apologize, shouldn't have said ultimate goal of evolution, I meant ultimate result of evolution will be that genes that are good at survival and passing themselves on will be around and others wouldn't. You can't say the same for machines, because machines will die out. Longevity of machines is not selected for after reproductive age. But longevity of genes is however the result of a gene that builds machines (along with other genes) that propagates it. Even though natural selection and evolution do not have purposes, natural selection does select for certain things. We used to think that natural selection will select for the phenotype that's best for species survival. In the selfish gene theory, natural selection selects for genes. It's the same process, but two different ways of understanding it. One of it sees it from the viewpoint of the organism, the other sees it from the viewpoint of the genes.

Hope that's not too convoluted.
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#7
RE: Selfish Gene Theory
(February 1, 2014 at 6:30 pm)pineapplebunnybounce Wrote: Hm, ok I see what you're struggling with. I won't be responding parts by parts because I think I may be able to explain it with more context in another order.

First mistake is that genes are not sets of DNA. A set of DNA is made up of multiple genes. So in sexual selection, genes still get passed on, entire ones, they don't split up and only pass on 50%. The benefit of sexual selection is diversity. The potato famine happened because all of the potatoes had the same DNA makeup and all got infected (or what do you call it). That wouldn't have happened if they did not propagate through cloning (exact replicates as offsprings). So if a huge bunch of machines can die, the genes within them get reduced chances of being copied pass this generation.
So in the analogy of the chromosome representing a book, the genes representing the chapters, and the DNA representing the text, you're saying that the chromosome contains all the genes ("chapters") of the male, not 50%, yes? That makes sense (if I'm right)...

Quote:Now, the next thing would be to understand that although genes are just genes and not a set of DNA, many of them would not survive (get passed on indefinitely) without the "help" of other genes. A single gene cannot make a machine. But a machine is necessary to protect and replicate the genes. Everything that you see at the phenotypic level was brought about by genes. Once upon a time, you were just a single cell, the genes (those in your DNA) coded for proteins and these proteins affected change that made that cell into a baby and then into an adult. But if you do not have the gene for hair, you wouldn't have hair. Even though it's part of the machine now, it is the result of a gene. That is the "foresight" that genes have. If you have a gene that allows you to feel pain, you will survive better than a machine without that gene. A lot of things are essential to your survival and all those, no matter how complicated, could not have happened if the gene for it wasn't there. Makes sense?

Yes! Thank you.

Quote:When I said genes still call the shots, I meant a lot of what you do, in fact maybe even all of it, you're only able to do because of your genes. If you did not have the genes for a human brain, you wouldn't be able to make decisions like you do now. And also, genes are constantly being translated into proteins that keep you alive, the process is not rigid and still responds to stimuli. So it does maintain a level of control that you do not have (you cannot will cancer away just because you want to). If you have "good genes" it means your set of genes makes a machine that is good at survival and reproduction.

Although it isn't really "foresight". Imagine asking a billion people to take a test without telling them what they'll be tested on. And then tell them if they fail they'll die. That's like natural selection. No gene can see the future and be like, right, I better modify myself a little bit and tell my neighbours to change A, B, C and D to prepare for the ice age. It's basically a lot of genes that make a lot of machines and some machines don't do well for whatever reason. So in hindsight, it seems as if the genes really have some sort of foresight, but of course they don't. So when I said a gene is pulling tricks, it really isn't. It was just "lucky" (by chance), to land beside a useful gene and therefore gets passed on when that useful gene is passed on.

And I apologize, shouldn't have said ultimate goal of evolution, I meant ultimate result of evolution will be that genes that are good at survival and passing themselves on will be around and others wouldn't. You can't say the same for machines, because machines will die out. Longevity of machines is not selected for after reproductive age. But longevity of genes is however the result of a gene that builds machines (along with other genes) that propagates it. Even though natural selection and evolution do not have purposes, natural selection does select for certain things. We used to think that natural selection will select for the phenotype that's best for species survival. In the selfish gene theory, natural selection selects for genes. It's the same process, but two different ways of understanding it. One of it sees it from the viewpoint of the organism, the other sees it from the viewpoint of the genes.

Hope that's not too convoluted.

That makes a lot of sense and I think I have a clearer understanding now...but a couple more questions. When the genes of the father and the genes of the mother produce a new genome, how is it decided which of the genes will be recessive? Also, does this mean genetic diversity increases with each new individual (that might be an obvious yes) and if so, is there a "capping" off where the propagation of a new phenotype deletes certain genetic material to reduce diversity within the genotype? That brings me to one last question...what determines which genes will be deleted? Is it random or is there some selective pressure? What is it? If it happens to be neighbors with other "good" genes? I apologize if these questions sound convoluted (your answers, I appreciate, are not).
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#8
RE: Selfish Gene Theory
(February 1, 2014 at 6:56 pm)Pickup_shonuff Wrote:
(February 1, 2014 at 6:30 pm)pineapplebunnybounce Wrote: Hm, ok I see what you're struggling with. I won't be responding parts by parts because I think I may be able to explain it with more context in another order.

First mistake is that genes are not sets of DNA. A set of DNA is made up of multiple genes. So in sexual selection, genes still get passed on, entire ones, they don't split up and only pass on 50%. The benefit of sexual selection is diversity. The potato famine happened because all of the potatoes had the same DNA makeup and all got infected (or what do you call it). That wouldn't have happened if they did not propagate through cloning (exact replicates as offsprings). So if a huge bunch of machines can die, the genes within them get reduced chances of being copied pass this generation.
So in the analogy of the chromosome representing a book, the genes representing the chapters, and the DNA representing the text, you're saying that the chromosome contains all the genes ("chapters") of the male, not 50%, yes? That makes sense (if I'm right)...

Uhmmmm .... What do you mean? XD.

I see now that I wasn't very careful with my terminology. Ok, so we have sets of genes in chromosomes. And DNA is basically the ATGC that make up chromosomes. And genes are ... chapters or words. I prefer words. But doesn't matter, same idea.

So you can split the book without splitting the chapters. Some genes will be cast off during sexual selection, in the form of sperms that did not get there first and in females, it just separates from the egg before ovulation and dies off.

Quote:
Quote:When I said genes still call the shots, I meant a lot of what you do, in fact maybe even all of it, you're only able to do because of your genes. If you did not have the genes for a human brain, you wouldn't be able to make decisions like you do now. And also, genes are constantly being translated into proteins that keep you alive, the process is not rigid and still responds to stimuli. So it does maintain a level of control that you do not have (you cannot will cancer away just because you want to). If you have "good genes" it means your set of genes makes a machine that is good at survival and reproduction.

Although it isn't really "foresight". Imagine asking a billion people to take a test without telling them what they'll be tested on. And then tell them if they fail they'll die. That's like natural selection. No gene can see the future and be like, right, I better modify myself a little bit and tell my neighbours to change A, B, C and D to prepare for the ice age. It's basically a lot of genes that make a lot of machines and some machines don't do well for whatever reason. So in hindsight, it seems as if the genes really have some sort of foresight, but of course they don't. So when I said a gene is pulling tricks, it really isn't. It was just "lucky" (by chance), to land beside a useful gene and therefore gets passed on when that useful gene is passed on.

And I apologize, shouldn't have said ultimate goal of evolution, I meant ultimate result of evolution will be that genes that are good at survival and passing themselves on will be around and others wouldn't. You can't say the same for machines, because machines will die out. Longevity of machines is not selected for after reproductive age. But longevity of genes is however the result of a gene that builds machines (along with other genes) that propagates it. Even though natural selection and evolution do not have purposes, natural selection does select for certain things. We used to think that natural selection will select for the phenotype that's best for species survival. In the selfish gene theory, natural selection selects for genes. It's the same process, but two different ways of understanding it. One of it sees it from the viewpoint of the organism, the other sees it from the viewpoint of the genes.

Hope that's not too convoluted.

That makes a lot of sense and I think I have a clearer understanding now...but a couple more questions. When the genes of the father and the genes of the mother produce a new genome, how is it decided which of the genes will be recessive? Also, does this mean genetic diversity increases with each new individual (that might be an obvious yes) and if so, is there a "capping" off where a phenotype deletes certain genetic material to reduce diversity? (that's probably another obvious yes but it brings me to one last question)...what determines which genes will be deleted? Is it random or is there some selective pressure? What is it? If it happens to be neighbors with other "good" genes? I apologize if these questions sound convoluted (your answers, I appreciate, are not).

Whether which gene will be recessive depends on the gene itself. There are different scenarios.

Example: 2 types of alleles in this particular gene. We'll call them A and B. The A allele is dysfunctional and doesn't get translated into proteins. The B allele codes a functional protein. So we have 3 possibilities: AA, AB, BB. In the case of AB, do you think the phenotype would resemble AA or BB? It would resemble BB because one B allele is enough to make enough proteins to manifest similar phenotypes as BB.

It's similar types of scenarios, sometimes one allele makes a dysfunctional protein except in the presence of another protein, etc. etc. And it's not as clean cut as they make it sound like in high school. There are genes with addition effect as well. So if a gene codes for melanin (for example, completely fictional), having 6 of it gives you a darker skin colour. Having 3 gives you a medium tone. And so on. So it doesn't have to be one gene dominant another recessive.

About genetic diversity, yes provided that the new organism is actually genetically diverse. In incest the diversity goes down every generation. Look into conservation science if you're interested in that, they talk about the minimum number of genetically diverse individuals you need to keep a population self sustainable.

There is a cut off to how many genes you can carry. Prokaryotes don't have a lot of genes because of size and maintenance takes energy that may be better spent elsewhere. That's partly why bacteria evolve so much quicker. Selection is very strong because genes keeps getting chucked away.

Selection isn't random. If you have a genetic disease and can't survive till reproduction your genes die with you. If that genetic disease is so deleterious that everyone with that defect dies before reproducing, you can imagine that it is strongly selected against, since it's chances of getting replicated is significantly lowered. Deletion/mutation is random, but whether the machine survives the mutation isn't random. If it's a silent gene (used to be known as junk DNA, now they're not sure if it's junk), anyway, if it's truly junk, deletion makes no difference. So as time goes along, deletion of that gene is likely to happen (this goes into probabilities). However if the same random deletion/mutation happens to an important gene, it would cause the death of the machine, causing that mutation to be selected against. If you look into genetics people talk about genes that are "highly conserved", meaning you find the same genes in almost all members of the species, it would mean the gene is really essential for survival. [/quote]
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#9
RE: Selfish Gene Theory
(February 1, 2014 at 7:18 pm)pineapplebunnybounce Wrote:
(February 1, 2014 at 6:56 pm)Pickup_shonuff Wrote: So in the analogy of the chromosome representing a book, the genes representing the chapters, and the DNA representing the text, you're saying that the chromosome contains all the genes ("chapters") of the male, not 50%, yes? That makes sense (if I'm right)...

Uhmmmm .... What do you mean? XD.

I see now that I wasn't very careful with my terminology. Ok, so we have sets of genes in chromosomes. And DNA is basically the ATGC that make up chromosomes. And genes are ... chapters or words. I prefer words. But doesn't matter, same idea.

So you can split the book without splitting the chapters. Some genes will be cast off during sexual selection, in the form of sperms that did not get there first and in females, it just separates from the egg before ovulation and dies off.

I believe Dawkins used the same analogy earlier in the book but I'm referring to this (relevant portion begins around the 9-minute mark): https://www.youtube.com/watch?v=OZIQTMHmWmg

As to the rest of your response, all I can say is, I'm jealous! I sure wish I could understand it well enough to regurgitate it as thoroughly and concisely as you do! Tongue
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#10
RE: Selfish Gene Theory
Ok, not quite sure what you're asking. Hm. So you have a set of chromosomes. It goes through meiosis and splits itself. The end result is sperm (you're a guy, right? XD), which contains only half. In the female it's an egg which also only has half. Those two come together to make a new full set. So half of your chromosomes don't get passed on, yea.

Oh and as for my familiarity with these subjects, it's the result of almost 4 years of university where I took courses in molecular genetics, evolution, ecology, animals, microbio, human physiology, neuroscience, other boring medical sciences and also some years of tutoring high school kids. It's also why I don't participate in debates with creationists unless it is to mock them. Can't stand it. But if you're interested in these things, textbooks are a good way to go but they're dry. IMO, to understand something you need to know the boring parts and not just the interesting parts, molecular anything is dead boring to me but it helps you understand so much when you zoom out and look at the big picture again.
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