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Faith  Suspended Member (Idle past 1444 days) Posts: 35298 From: Nevada, USA Joined: |
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Author | Topic: Evolution Requires Reduction in Genetic Diversity | |||||||||||||||||||||||||||||||||||||||
Dr Adequate Member (Idle past 284 days) Posts: 16113 Joined:
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You might as well be arguing that rivers should run dry in a year's time because rivers only flow downhill, they can't flow uphill to replenish the water flowing downhill. Just as rain replenishes the water needed to flow downhill. so too does mutation produce the new genetic diversity that flows through selection. Good analogy. Maybe better than mine, but in any case they're along the same lines. The thing is that Faith is basing her argument on deliberately ignoring facts known to her. For example, she says:
Faith writes: The variation that everybody is talking about comes in at a different point in the life of the species. [...] The variation you keep wanting me to take into account simply does not enter into what I'm trying to get said. She knows that the total evolutionary process involves the introduction of variation, just as she knows that the water cycle involves evaporation and rain, and she knows that walking involves motion of the right foot. But then, she feels free to say: "The variation you keep wanting me to take into account simply does not enter into what I'm trying to get said". That is, looking at all the facts would destroy her argument. And from her point of view, that's actually a reason to ignore them, because: "The variation you keep wanting me to take into account simply does not enter into what I'm trying to get said". What can one say to someone like this? To us, arguments should be based on the facts, but she feels entitled to ignore the facts known to her, and undisputed by her that don't support "what I'm trying to get said". Rivers will run dry, and walking is impossible. We can prove that, so long as we ignore facts that we know perfectly well.
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Faith  Suspended Member (Idle past 1444 days) Posts: 35298 From: Nevada, USA Joined: |
New mutations occur in reproductively isolated and inbreeding populations as well. So what? Edited by Faith, : No reason given.
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Faith  Suspended Member (Idle past 1444 days) Posts: 35298 From: Nevada, USA Joined:
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This thread has gone to the dogs in the last few hours and I'm too annoyed to bother dealing with it now. Maybe later if there's anything worth trying to deal with. You guys don't seem to recognize you are just proliferating straw man arguments and raising objections I've already answered and I have to leave to get my blood pressure down in any case.
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Dr Adequate Member (Idle past 284 days) Posts: 16113 Joined:
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And so we get comedy like this:
"Removes diversity overall?" Where are you getting that? I'm talking about how diversity is REDUCED (sometimes eliminated but ALWAYS reduced) by the fact that alleles that don't contribute to the new phenotype simply are not present in that gene pool or the phenotype would not develop. So it's like: ""The right foot never moves"? Where are you getting that? I'm talking about how it is stationary when it stands still." She doesn't realize that she's abandoned the condition that would actually make her argument work. It's an undeniable truth when she's founding her argument on it, and she doesn't believe a word of it when someone suggests that she's naive enough to believe it.
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herebedragons Member (Idle past 857 days) Posts: 1517 From: Michigan Joined:
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The initial diversity before the Flood was so great that enormous diversity remained in the creatures on the ark. This is all speculative of course but I think you need to think of every gene of every individual as being heterozygous, the maximum genetic diversity you could have, two alleles per gene, and different in each individual as well so that you do have four alleles for each pair of animals, It seems as if you are thinking of this as if you have this giant pool of diversity from which you could select phenotypes from. In other words, if you have 20,000 genes and 50% heterozygous you could have up to 40,000 different phenotypes. (I am sure that is an exaggerated estimate and you aren't necessarily suggesting that, but I am trying to illustrate the concept of diversity that it seems like you have) But in reality, you have to look at the diversity at a single loci. There are traits that are controlled by a single gene and for this idea to work, the diversity of these traits need to be explained adequately. I am going to give you some examples of monogenic traits that have multiple alleles. When you start out with only 4 alleles and reduce genetic diversity, you won't come up with 4 or more alleles at any given loci.
Drosophila eye color - 7 different alleles + = redw = white wch = cherry we = eosin wapr = apricot wiv = ivory wch = cream Austrialian Sheperd - 3 and 4 alleles As = no copperay = sable at = copper (white trim)S = little or no white sp = pie bald si - irish trim s = extreme white C series in dogs - 5 alleles C = coat color expressedcch = chinchilla cd = white with dark eyes cb = pale gray c = albino coat color in siamese cats - 4 alleles c+ = standardcb = Birman cs = siamese ca - albino Most people are familiar with the 3 alleles that are associated with the human ABO blood system. But what is less familiar is that there are more than 30 blood group systems that are complicate blood transfusions. Blood group systems This website Complex Expression says that
quote: That is an average of 25 alleles per gene! Most of these are rare and are usually not designated when referring to blood type. BTW, you should read through that site I linked above, complex expression, it has some good information on gene expression. These are just some examples of relatively easy to find examples of multiple alleles even in domesticated animals. There are certainly many more examples but they probably have not been studied adequately. It is rather complex to unravel genes with multiple alleles. I showed you all of this to explain why I don't think it makes sense that the genome started out with 4 alleles and has undergone subsequent reduction in diversity. Mutant alleles must come into play, even in your scenario. There is more I want to say here but I just don't the have time right now. HBDWhoever calls me ignorant shares my own opinion. Sorrowfully and tacitly I recognize my ignorance, when I consider how much I lack of what my mind in its craving for knowledge is sighing for. But until the end of the present exile has come and terminated this our imperfection by which "we know in part," I console myself with the consideration that this belongs to our common nature. - Francesco Petrarca "Nothing is easier than to persuade people who want to be persuaded and already believe." - another Petrarca gem.
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NoNukes Inactive Member
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I have to leave to get my blood pressure down in any case. This thread has gone to the dogs in the last few hours and I'm too annoyed to bother dealing with it now. It must indeed be frustrating to know more about evolution than any of the scientists posting in the thread, and to yet be unable to teach them anything. Best to just give every counter argument a jeer and be done with it. Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846) The apathy of the people is enough to make every statue leap from its pedestal and hasten the resurrection of the dead. William Lloyd Garrison. If there is no struggle, there is no progress. Those who profess to favor freedom, and deprecate agitation, are men who want crops without plowing up the ground, they want rain without thunder and lightning. Frederick Douglass
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Taq Member Posts: 9972 Joined: Member Rating: 5.5
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So what? This means that genetic diversity starts to increase after a strong selection event.
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Taq Member Posts: 9972 Joined: Member Rating: 5.5 |
I'm talking about how diversity is REDUCED (sometimes eliminated but ALWAYS reduced) by the fact that alleles that don't contribute to the new phenotype simply are not present in that gene pool or the phenotype would not develop. How do you get a new phenotype other than through an increase in genetic diversity? How do you get competition between alleles without the production of new alleles which is an increase in genetic diversity? If we start with 100% allele A and later end up with 50% allele A and 50% allele B, would you count this as an increase in genetic diversity?
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DBlevins Member (Idle past 3775 days) Posts: 652 From: Puyallup, WA. Joined: |
I don't want to gang up on Faith so I'll just make a point here that I think she might be missing that I'm not sure if you might have brought up already.
There is a difference between genotype and phenotype, such that a large beaked bird may still have within it's genotype the genes for a smaller beak, just as it is possible for a brown eyed human to have a gene for blue eyes. Faith seems to believe that when a new variation comes into play, it totally wipes out all other genes and there is no such thing as recessive or unexpressed genes.
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Faith  Suspended Member (Idle past 1444 days) Posts: 35298 From: Nevada, USA Joined: |
don't want to gang up on Faith so I'll just make a point here that I think she might be missing that I'm not sure if you might have brought up already. There is a difference between genotype and phenotype, such that a large beaked bird may still have within it's genotype the genes for a smaller beak, just as it is possible for a brown eyed human to have a gene for blue eyes. Faith seems to believe that when a new variation comes into play, it totally wipes out all other genes and there is no such thing as recessive or unexpressed genes. No, I don't believe that, it's just that I can't get the entire picture described in a brief post and i expect such questions to come up later. Unfortunately they come up later as accusations that I never thought of them. If people would DISCUSS instead of barraging, attacking, accusing and ridiculing such facts would eventually get discussed. The idea is that the other beak is in the gene pool but less and less expressed as the chosen beak dominates -- I do keep saying the genetic diversity is "reduced," it's rare that an allele is completely eliminated but it does happen with sharply reduced numbers and also at the far reaches of the process I'm describing. The emphasis is on REDUCED to that point.
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Taq Member Posts: 9972 Joined: Member Rating: 5.5 |
The idea is that the other beak is in the gene pool but less and less expressed as the chosen beak dominates If it can be shown that the other beak comes about due to a new mutation, would you count this as an increase in genetic diversity?
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Faith  Suspended Member (Idle past 1444 days) Posts: 35298 From: Nevada, USA Joined: |
How do you get a new phenotype other than through an increase in genetic diversity? The gene pool contains all the alleles for all the variations, no increase is needed. If you want to think they were created by mutations, I'll tolerate that idea up to a point, but it would be silly to think a brand new mutation is always going to be selected as the basis of a new phenotype when the gene pool is full of alleles for all kinds of variations anyway. When a new smaller population splits off the idea is that it contains a different mix of alleles than the mother population had and those that dominate in the new will be different than those in the old and that's what brings about a new phenotype. The alleles for the same genes that make up that phenotype that are not used in that phenotype are fewer in number and could eventually be eliminated from the gene pool altogether.
How do you get competition between alleles without the production of new alleles which is an increase in genetic diversity? The alleles already exist, Taq, whether they were created by mutation or built in at the beginning. You've got a ton of genetic diversity in the collection of alleles in the gene pool. Why are you guys always assuming you need new ones? If you're right and mutation is the source of alleles, then I guess you'll get some new ones but there's no guarantee the newer mutations will be selected anyway, why should they be? As to new alleles being increased diversity, yeah in a way, but again all a mutation can do is vary whatever the gene it affects does, which there are probably alleles in the population already doing, and when a new phenotype gets selected they're treated like any allele anyway, they either become part of the phenotype or they are suppressed or eliminated
If we start with 100% allele A and later end up with 50% allele A and 50% allele B, would you count this as an increase in genetic diversity? Sure. But I have no doubt there are already Bs and Cs and all the rest in the gene pool to begin with. Edited by Faith, : No reason given.
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Faith  Suspended Member (Idle past 1444 days) Posts: 35298 From: Nevada, USA Joined: |
If it does, it's replacing another allele for beak type anyway you know, and surely all the possible beak types are already present in the gene pool so this "increase in diversity" is redundant and as I keep pointing out, once it gets selected the genetic diversity starts getting reduced anyway so it really amounts to nothing new in the end.
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Faith  Suspended Member (Idle past 1444 days) Posts: 35298 From: Nevada, USA Joined: |
I'm aware of the problem you bring up and don't know how to solve it yet but yes it is possible some kind of mutation makes up the greater number of alleles than the gene locus allows.
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Taq Member Posts: 9972 Joined: Member Rating: 5.5 |
If it does, it's replacing another allele for beak type anyway you know, and surely all the possible beak types are already present in the gene pool so this "increase in diversity" is redundant and as I keep pointing out, once it gets selected the genetic diversity starts getting reduced anyway so it really amounts to nothing new in the end. Once it appears, the genetic diversity has increased, has it not? It would seem to me that you have competing mechanisms: one that increases genetic diversity and one that decreases genetic diversity.
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