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Author | Topic: Explaining the pro-Evolution position | |||||||||||||||||||||||||||||||||||||||
Kleinman Member (Idle past 334 days) Posts: 2142 From: United States Joined: |
quote:Well if it isn't the multiplication rule of probabilities which has led to the success of combination therapy for the treatment of HIV, then what is it? What do you think is suppressing the evolution of drug-resistant variants in this circumstance?quote:Quite obviously it is not. To anyone with a proper understanding of probability theory. I already explained why it is not.
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Modulous Member Posts: 7801 From: Manchester, UK Joined:
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The first half of the cycle consists of a beneficial mutation occurring Nope. Any mutation.
the other half of the cycle (natural selection) consists of amplification of that beneficial mutation in order to improve the probability of the next beneficial mutation occurring on some member of that population who has the previous beneficial mutation. Nope. Natural selection is one process by which some alleles increase in frequency, others decrease in frequency and others retain their frequency. There is no purpose, reason or intent to change the frequencies. Thus 'beneficial mutations' are not increasing in frequency SO THAT they can accrue more beneficial mutations to their lineage. They increase in frequency because the mutation increases their replicative success SO they increase in frequency by virtue of how numbers work.
There can be competition between different variants if there are limited resources in the environment. rmns works best in environments that are not limited in the resources. This is nonsense. It is wrong. It is not supported by data. It is falsified by data. As far as it can be said to be a coherent claim. But then 'works best' is scientifically meaningless, so a true assessment is impossible.
Selection pressures kill or impair the ability of some or all members in a population to reproduce. These pressures can vary in intensity. Exactly. So saying that the selection pressures in one case demonstrates evolution is impossible in other cases is kind of silly isn't it?
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PaulK Member Posts: 17822 Joined: Member Rating: 2.3 |
quote: Trying to change the subject is hardly a good argument. I have already explained the problem with your use of probability Message 95 Now perhaps you could start by acknowledging that the multiplication rule for probabilities is in no way a roadblock to generating sequences of arbitrarily low probability. Do you even understand that much ? Edited by PaulK, : No reason given.
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Kleinman Member (Idle past 334 days) Posts: 2142 From: United States Joined: |
quote:This mathematical theorem is a physical roadblock to the accumulation of beneficial mutations on a lineage. If at any time the lineage does not amplify, the probabilities of another beneficial mutation occurring on that lineage are low. quote:There's nothing from preventing you from winning a hundred lotteries, well nothing except the multiplication rule of probabilities. quote:Bingo, you just won your second lottery. Just hope that you don't have to win two lotteries at the same time in order to win your prize.
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Kleinman Member (Idle past 334 days) Posts: 2142 From: United States Joined: |
quote:You are making an assumption that the energy fit variants will not be inhibited from reproducing when held at sub-optimal temperatures. There's a reason laboratories run their incubators at particular temperatures. And Taq, you still haven't answered my simple question to you. Does doubling population size double the probability of a beneficial mutation occurring?
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Kleinman Member (Idle past 334 days) Posts: 2142 From: United States Joined: |
quote:How does evolution of drug resistance differ than evolution by rmns to any other kind of selection pressure? What is the mathematical difference between Lenski's experiment and let's say this experiment: Scientists create video of bacteria evolving drug resistance.
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Taq Member Posts: 9970 Joined: Member Rating: 5.6 |
Kleinman writes: You are making an assumption that the energy fit variants will not be inhibited from reproducing when held at sub-optimal temperatures. The effect of thermal stress would be the same for both the energy fit and the less energy fit. This would allow the energy fit to outcompete the less energy fit.
Does doubling population size double the probability of a beneficial mutation occurring? It doubles the probability of any mutation occurring at a specific locus.
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Taq Member Posts: 9970 Joined: Member Rating: 5.6 |
Kleinman writes: How does evolution of drug resistance differ than evolution by rmns to any other kind of selection pressure? Selection pressures are rarely binary between survival and death. It wasn't as if a species with scales would go extinct in a single generation if it didn't evolve feathers.
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Taq Member Posts: 9970 Joined: Member Rating: 5.6 |
Kleinman writes: Try climbing two different flights of stairs at the same time. That's exactly what sexual species do.
You win a lottery, everyone wants to marry you. Your tacit admission of defeat is accepted.
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PaulK Member Posts: 17822 Joined: Member Rating: 2.3 |
quote: If you had been paying attention you would know. For drug resistance selection pressure comes in the form of an environmental factor which greatly reduces the fitness of all non-resistant members of the population. What happens in the case of soft selection where the fitness of the "original" strain remains high ? Where the only factor reducing it below 1 is competition with other members of the species who possess a recent mutation (or a mutation recently become advantageous due to environmental change)
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Kleinman Member (Idle past 334 days) Posts: 2142 From: United States Joined: |
quote:Starvation will deplete the energy from many biochemical pathways. If you are going to try to find the targets for this kind of selection pressure, look at the pathways which require the most energy. Lenski's experiment works because he doesn't starve his populations to death. Lenski also did an experiment with thermal stress and it is well known that the conformation of enzymes is temperature dependent. To find the targets for thermal stress, look for the enzymes whose activities are most affected by temperature. So if you put starvation pressure and thermal stress on the population at the same time, well you figure it out. quote:Why doesn't anything evolve resistance to Iodine? The reason is that Iodine is a very reactive molecule binding to all kinds of biological molecules, denaturing the molecules, far too many targets for rmns to have any chance for a replicator to evolve resistance to this chemical.
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Kleinman Member (Idle past 334 days) Posts: 2142 From: United States Joined: |
quote:What do you think happens if the mutation is detrimental? quote:rmns is not dependent on the relative frequency of variants in a population. quote:Here's an example where rmns is occurring in an environment where variants are not competing for resources in the environment: Scientists create video of bacteria evolving drug resistance. The Lenski experiment, on the other hand, has his variants competing for the resources of the environment. quote:Feel free to quote me if you think I said that. What I have said and will continue to say because it is a mathematical and empirical fact of life is that rmns only works efficiently when a single gene is targeted by a single selection pressure at a time. And this process does not work by changing the relative frequencies of variants in a population but works by amplification of the particular variants.
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Modulous Member Posts: 7801 From: Manchester, UK Joined: |
Lenski's experiment works because he doesn't starve his populations to death. Yup.
So if you put starvation pressure and thermal stress on the population at the same time, well you figure it out. All things being equal it would take the same generational time as the starvation experiment plus the generational time of the thermal stress experiment. That is, if the second experiment was as lethal as the first (ie., the number of bacteria that died without reproducing in the starvation experiment is the same the number of bacteria dying w/o reproduction in the starvation + thermal stress test), then it would just be a case of evolving one (which we know how long that takes) then evolving the other (and we know that too). If the experiments were MORE lethal, then they couldn't be easily compared, we'd need to know population size per generation before being able to estimate. That's a bit like the difference between being a dinosaur in a normal environment and a virus being bombarded with disparate poisons that have been tailored to kill it. One is a little more lethal and the results consequently may differ.
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Taq Member Posts: 9970 Joined: Member Rating: 5.6 |
Kleinman writes: So if you put starvation pressure and thermal stress on the population at the same time, well you figure it out. Perhaps you should figure it out.
Why doesn't anything evolve resistance to Iodine? The reason is that Iodine is a very reactive molecule binding to all kinds of biological molecules, denaturing the molecules, far too many targets for rmns to have any chance for a replicator to evolve resistance to this chemical. You claim that RMNS can't produce the features we do see. Why don't you focus on the features we do see instead of the features we don't see.
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Kleinman Member (Idle past 334 days) Posts: 2142 From: United States Joined: |
quote:What you are not seeing is that the thermal stress will be impairing the replication of the energy fit variants when compared to running the experiment at the ideal temperature. The ability to amplify any beneficial mutation for a given selection pressure can and is impaired by other selection pressures. quote:So if the probability of a beneficial mutation occurring for a population size N is let's say 0.6 and you double the population size to 2N, the probability becomes 1.2? What you've done here (and it is commonly done) is confuse complementary events (does the mutation occur or doesn't it occur) with additive events (like the probability of rolling a 1 or a 2 with a fair die). Here's a more detailed explanation if you are interested. Let's say you want to compute the probability of rolling at least a single 1 with two rolls of a die. The probability of rolling 1 with a single roll is 1/6. If you roll the die a second time, the probability of rolling the 1 is again 1/6. But you don't add 1/6+1/6=1/3 to compute the probability of getting at least a single 1, the correct value is 11/36. Try and understand why.
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