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Author | Topic: Explaining the pro-Evolution position | |||||||||||||||||||||||||||||||||
Tangle Member Posts: 9489 From: UK Joined: Member Rating: 4.9
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Kleinman writes: If natural selection is not altering the probabilities that a particular mutation will occur at a particular site in a genome, then what do you think that natural selection does? Oops, that's embarassing.Je suis Charlie. Je suis Ahmed. Je suis Juif. Je suis Parisien. Life, don't talk to me about life - Marvin the Paranoid Android "Science adjusts it's views based on what's observed.Faith is the denial of observation so that Belief can be preserved." - Tim Minchin, in his beat poem, Storm.
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PaulK Member Posts: 17822 Joined: Member Rating: 2.2 |
quote: Natural selection increases the probability that a beneficial mutation will be retained (and spread) in a population and the probability that deleterious mutations will be lost.
quote: You have been extremely evasive about your argument and now it turns out that you have made a basic error. And I am certainly not going to apologise for disagreeing with your erroneous opinion.
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Kleinman Member (Idle past 335 days) Posts: 2142 From: United States Joined: |
quote: They are rare events when a particular mutation must occur at a particular site in the genome to improve fitness. And natural selection must do something specifically to improve the probability that a particular mutation will occur at a particular site in a genome to improve fitness. If you think that mutations are not random, you need to give us an empirical example of this claim.
quote:In any stochastic process, it is not possible to predict the outcome of any random experiment. What probability theory does is enable one to predict the relative frequencies of outcomes when the random experiment is done many times. A simple example is tossing a coin. You can not predict whether a head or a tail comes up with any toss. What you can predict is that if you toss the coin many times, about half the outcomes will be heads, the other half of the outcomes will be tails. quote: Any particular mutation at any particular site. What I'm trying to get at is the definition of mutation rate. The mutation rate is the probability that mutation will occur at a given site in the genome in a single replication.
quote: It certainly does, natural selection changes the probabilities of particular mutations occurring by changing population sizes.
quote: You are changing the mutation rate but you are not changing the fact that mutations are random events. Mutation rates are a factor when computing the probabilities of a particular beneficial mutation occurring but there is a much more important factor for rmns to work.
quote: You need to give us an empirical example where a mutation is not a random event. Random means something that occurs by chance, not predictable. What Weinreich is talking about, for an evolutionary trajectory to have a reasonable probability of occurring, the sequence of mutations must always give improved fitness to reproduce.
quote: Natural selection in the Weinreich experiment is not random but the mutations which give improved fitness are random. Natural selection can also be random but in that case, we are not talking about rmns. So how does non-random natural selection and random mutation work?
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Kleinman Member (Idle past 335 days) Posts: 2142 From: United States Joined: |
quote:Ok, so those members with a beneficial mutation will increase in number. How large does that lineage have to be in order for there to be a reasonable probability of another beneficial mutation occurring on a member of that lineage? quote:My argument is not complicated but it is not trivial. I'm trying to teach you something about rmns that you have missed. Your above quote is taking you on the correct path to understand this phenomenon. If you think I have made an error, feel free to post my quote.
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PaulK Member Posts: 17822 Joined: Member Rating: 2.2 |
quote: Obviously that depends on the number of beneficial mutations available. But bear in mind that bacteria have very large populations, very short generation times and can share genetic material quite freely.
quote: At this point it looks more like an attempt to get other people to do the work that you have not (and assuming the result). Anyway, your assertion that natural selection "must" increase the probability of a beneficial mutation occurring is an obvious error.
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Coyote Member (Idle past 2106 days) Posts: 6117 Joined: |
If natural selection is not altering the probabilities that a particular mutation will occur at a particular site in a genome, then what do you think that natural selection does? Natural selection kills off the also-rans.Religious belief does not constitute scientific evidence, nor does it convey scientific knowledge. Belief gets in the way of learning--Robert A. Heinlein In the name of diversity, college student demands to be kept in ignorance of the culture that made diversity a value--StultisTheFool It's not what we don't know that hurts, it's what we know that ain't so--Will Rogers If I am entitled to something, someone else is obliged to pay--Jerry Pournelle If a religion's teachings are true, then it should have nothing to fear from science...--dwise1 "Multiculturalism" demands that the US be tolerant of everything except its own past, culture, traditions, and identity.
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Kleinman Member (Idle past 335 days) Posts: 2142 From: United States Joined: |
quote:If you are going to consider the mathematics of rmns, you have to consider the size of lineages in populations, not the entire population size when computing probabilities. A beneficial mutation for one lineage may not be a beneficial mutation for a different lineage. That's what the Weinreich example is demonstrating. quote:I assure you that I have already done the mathematics for rmns. Do you think in the Weinreich example that all 5 beneficial mutations occur simultaneously to give resistance to the antibiotic selection pressure? Natural selection must do something to the lineages in this population for those 5 beneficial mutations accumulate on a lineage. And that something is increase the number of members with the beneficial mutations as you previously pointed out. What happens to the probabilities of a beneficial mutation occurring if the number of members who would benefit do not increase?
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Kleinman Member (Idle past 335 days) Posts: 2142 From: United States Joined: |
quote:True, but the also-rans are not the ones evolving resistance to the selection pressures. To understand rmns, you need to consider what happens to those variants who are lucky enough to get the beneficial mutations.
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NoNukes Inactive Member |
Natural selection is totally relevant. Natural selection must do something very specific in order to improve the probability that a beneficial mutation will occur. According to the theory of evolution, natural selection affects the probability that a given mutation is actually beneficial. It is not required that natural selection affect the actual probability that mutations, beneficial or not, actually occur. After all, whether or not a given mutation is beneficial is at least in part associated with environmental factors. Examples of genetic changes that are beneficial/non-beneficial based on the environment and natural selection include melanin affecting mutations, lactase intolerance persistance, and sickle cell anemia. If you want to argue from the premise you have presented here, you need to lay ground work to establish that your assertion is correct. So far you have not done so. Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846) History will have to record that the greatest tragedy of this period of social transition was not the strident clamor of the bad people, but the appalling silence of the good people. Martin Luther King I never considered a difference of opinion in politics, in religion, in philosophy, as cause for withdrawing from a friend. Thomas Jefferson Seems to me if its clear that certain things that require ancient dates couldn't possibly be true, we are on our way to throwing out all those ancient dates on the basis of the actual evidence. -- Faith
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Kleinman Member (Idle past 335 days) Posts: 2142 From: United States Joined: |
quote:What determines whether a mutation is beneficial or not is whether it affects the fitness to reproduce. You are correct, I should lay more groundwork to establish that my assertions are correct. Let's start with the fundamental principles of doing the mathematics of a stochastic process, in particular rmns. The first step in doing this type of mathematics is identifying the random trial(s) (experiment(s)) and possible outcomes for the random trial(s). In the case of rmns, there are two random trials. The first and key random trial is the replication of a genome. There are two possible outcomes for this random trial, a mutation does occur at a particular site in the genome or a mutation does not occur at a particular site in a genome. So we are dealing with a simple binomial probability problem. I'll talk about the second trial in a later post.
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Genomicus Member (Idle past 1942 days) Posts: 852 Joined: |
Good, you are on the right track for understanding how random mutation and natural selection (rmns from here on) works. I am quite familiar with population genetics and molecular evolution, but sure, yeah -- thanks for your laudatory comments I guess?
So consider the simpler case when HIV evolves very rapidly to single drug therapy. How do compute this probability? We'd need to know population size, fitness of wildtype viruses compared to drug-resistant mutants, mutation rate, no. of copies of mutant phenotype in the population, etc., to estimate probability of fixation of the drug-resistant mutation. But get to the point. You don't need to walk me through pop genetics.
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Kleinman Member (Idle past 335 days) Posts: 2142 From: United States Joined: |
quote:The compliment was sincere. But being familiar with population genetics as it is taught today is not going to help you with rmns. quote:The point of doing the probability calculations is to determine the population size necessary based on a given mutation rate to determine the probability of a beneficial mutation occurring. Fixation of a given variant is neither necessary nor sufficient for this process to work. It is even possible for the relative frequency of a variant in a population to decrease yet the variant is still able to evolve to the selection pressure.
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jar Member (Idle past 394 days) Posts: 34026 From: Texas!! Joined: |
Kleinman writes: Natural selection must do something very specific in order to improve the probability that a beneficial mutation will occur. Utter and complete bullshit. Total crappola. Sorry but that is simply so wrong that at best it might be considered a poor attempt at a sophomoric joke. Natural select simply selects those things that are not so destructive that the critter cannot live long enough to reproduce. The mutations that happen are totally unrelated to Natural Selection as anyone over the age of about ten should be able to understand. The mutations happen. Good mutations happen. Neutral mutations happen. Destructive mutations happen. Natural Selection don't really give a damn. Natural Selection has NOTHING to do with what mutations happen. Stop making such utterly stupid assertions, please.
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Kleinman Member (Idle past 335 days) Posts: 2142 From: United States Joined: |
quote:I wonder if you will ever understand how rmns works. It requires some skill in physics and mathematics. Perhaps you want to give it a shot and explain why combination therapy works for the treatment of HIV.
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kjsimons Member Posts: 821 From: Orlando,FL Joined: Member Rating: 6.7 |
Coyote writes: Natural selection kills off the also-rans. And/or decreases the amount of genetic material passed on. Not all selection is about killing off an individual.
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