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Author | Topic: Explaining the pro-Evolution position | |||||||||||||||||||||||
Kleinman Member (Idle past 334 days) Posts: 2142 From: United States Joined: |
quote:That's the point, Lenski is using only a single directional selection pressure, starvation. He is selecting for the most efficient energy users. And if Lenski were to add a second simultaneous selection pressure, for example, thermal stress, the amplification of the mutations which increase energy efficiency will be slowed by the thermal stress applied to these populations. Now if you want to get variants which are thermal stress tolerant and energy efficient replicators, use the selection pressures sequentially. Contact Lenski and ask him to do the experiment and prove me wrong.
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Kleinman Member (Idle past 334 days) Posts: 2142 From: United States Joined: |
quote:Don't get me wrong Doc, allele frequencies are important when you are considering random recombination. But when it comes to rmns, it's the actual population size for a given lineage that is important and used to determine the probabilities (that and the number of generations the lineage replicates), not the relative frequency of the particular variant wrt the rest of the population. For a lineage on a particular rmns evolutionary trajectory, it doesn't matter what other lineages are doing (unless those other lineages are competitors for the resources of the environment).
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Taq Member Posts: 9970 Joined: Member Rating: 5.6 |
That's the point, Lenski is using only a single directional selection pressure, starvation. He is selecting for the most efficient energy users. And if Lenski were to add a second simultaneous selection pressure, for example, thermal stress, the amplification of the mutations which increase energy efficiency will be slowed by the thermal stress applied to these populations. As long as the thermal stress was not lethal, the adaptation for energy efficiency would not be slowed. Bacteria with adaptations to just one of the selection pressures would outcompete bacteria with none of the adaptations.
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Kleinman Member (Idle past 334 days) Posts: 2142 From: United States Joined: |
quote:There's some very smart people who peer reviewed and published my work on rmns. They see the importance of understanding the physics and mathematics of rmns because of its impact on the evolution of drug resistance.
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Kleinman Member (Idle past 334 days) Posts: 2142 From: United States Joined: |
quote:Are you suggesting that putting a bigger gun and more armor on a tank are random processes? quote:That may be true but the probability for that member getting both those beneficial mutations is computed using the multiplication rule, not the addition rule. Here's a simple question for you Taq. If you double the population size, do you double the probability that a beneficial mutation will occur?
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PaulK Member Posts: 17822 Joined: Member Rating: 2.3 |
Your problem is not understanding rmns in terms of drug resistance. Your problem is that you refuse to understand that drug resistance is a special case. And you will never understand rmns until you take off those blinkers and consider it in other contexts.
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Taq Member Posts: 9970 Joined: Member Rating: 5.6 |
Kleinman writes: Are you suggesting that putting a bigger gun and more armor on a tank are random processes? It's an analogy, chief.
That may be true but the probability for that member getting both those beneficial mutations is computed using the multiplication rule, not the addition rule. You are wrong. Both beneficial alleles will become common in the population, making offspring with both beneficial alleles a nearly unavoidable outcome. The appearance of individuals with both beneficial alleles will only be limited by the least beneficial allele spreading through the population. The time needed to start seeing individuals with both beneficial alleles is much, much less than your claimed multiplicative probability.
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Dr Adequate Member (Idle past 284 days) Posts: 16113 Joined: |
That's the point, Lenski is using only a single directional selection pressure, starvation. But this exerts pressure on a whole lot of loci. Why would it make a difference if each locus had the same amount of pressure on it, but from a different underlying environmental cause? How in the world would that show up in the math? By the time you've put it into numbers and put the numbers into the equations, you can't tell if both loci are under pressure from starvation, or if one is under pressure from starvation and the other from fire-breathing dragons. That disappears from the math just like the color of objects disappears from problems in kinetics. Unless you can show me some math which does take into account the causes of the pressures, and explain to me how and why it does so ...
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Taq Member Posts: 9970 Joined: Member Rating: 5.6 |
Kleinman writes: There's some very smart people who peer reviewed and published my work on rmns. They see the importance of understanding the physics and mathematics of rmns because of its impact on the evolution of drug resistance. Evolution of drug resistance is a really poor model for things like the evolution of feathers. Quite obviously, tetrapods with scales instead of feathers are still doing quite well. They aren't facing complete extinction in one generation if they don't develop feathers all at once. What feathers allowed a lineage to do is move to a niche with less competition. This is VERY different from the evolution of drug resistance.
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Dr Adequate Member (Idle past 284 days) Posts: 16113 Joined: |
I would think that it would be self evident. Not quite; maybe I don't know enough about medicine. But I would have thought that since no drug is 100% effective, each drug is just getting a shot, with a certain probability of success, of killing each viral particle. One which is immune to one of the drugs (I would have thought) would therefore have a greater probability of survival. Stop me if I'm wrong.
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Kleinman Member (Idle past 334 days) Posts: 2142 From: United States Joined: |
quote:Recombination can occasionally create chimeric alleles but they are simply handled in the "..." term of the possible outcomes for a mutation. But by far, most recombination events do not create new alleles.
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PaulK Member Posts: 17822 Joined: Member Rating: 2.3 |
I would expect resistance to one drug to have a small benefit. The important thing is that the fitness remains noticably less than 1, even with resistance to one drug.
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Kleinman Member (Idle past 334 days) Posts: 2142 From: United States Joined: |
quote:rmns consists of a cycle. The first half of the cycle consists of a beneficial mutation occurring, 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. quote: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. quote:Selection pressures kill or impair the ability of some or all members in a population to reproduce. These pressures can vary in intensity.
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Kleinman Member (Idle past 334 days) Posts: 2142 From: United States Joined: |
quote:Ok, go for it, how much time for a generation for your dinosaur. quote:Because the mutation rate is going to be higher than the beneficial mutation rate. quote:--- given enough time and your population doesn't go extinct.
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Kleinman Member (Idle past 334 days) Posts: 2142 From: United States Joined: |
quote:Try climbing two different flights of stairs at the same time. quote:You win a lottery, everyone wants to marry you.
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