Kleinman said:
Evolutionary optimization techniques are particularly useful in situations in which it is easy to determine the quality of a single solution, but hard to go through all possible solutions one by one (it is easy to determine the driving time for a particular route of the delivery truck, but it is almost impossible to check all possible routes once the number of destinations grows to more than a handful)
You've got to be kidding me. I had the feeling that comprehension of the written word was not your strong suit based on the responses you have created to my queries, but this simply takes the cake. You are quoting me a passage that tells you that evolutionary optimization techniques work better if we have a problem that we can't solve easily when we have to sort through the problem one solution at a time because evolutionary optimization can solve the multiple problems all at the same time? You know, parallel processing? To quote Inigo Montoya, "You keep using that word. I do not think it means what you think it means."
Joobz already answered this, why do you insist on making such a fool of yourself?
This applies to selection pressures that do not completely block reproduction.
Great. Then by that logic, evolution with multiple selection pressures that do not completely block reproduction (which is the usual state of affairs) is not slowed and should work mighty fine, mighty fine indeed, sir. This is precisely what I have been telling you for several pages. So you now agree?
the example of triple antiviral agents for the treatment of HIV demonstrates this.
Triple antiviral agents for HIV demonstrates that if you block replication, then there simply cannot be many offspring for the next generation. Triple therapy doesn't tell us anything about the number of selection pressures necessary to block replication in every organism, it tells us that strong selection pressures are strong. Three strong selection pressures are stronger as a selection pressure than one strong one if there is considerable variability in the organism. If the selection pressures are weak, however, as is the case most of the time in nature, then you have already signed onto the propostion that evolution works on each of those pressures at the same time to find a solution -- no slowing. That is what the fitness landscape shows.
Of course you are not playing the game, you can’t even see the goalposts.
We are discussing your analogy. Got it?
I’ve already explained to you two ways in which triple antiviral slow the evolution of drug resistant strains of HIV, but since you are having a difficult time understanding this concept, I’ll repeat these points again. The first way triple antiviral agents slow the evolution of drug resistant strains of HIV is that it requires at least three mutations to occur at appropriate loci for a fully resistant strain of the virus to appear. Even if one or two mutations occur at appropriate loci, the still effective third drug will continue to slow reproduction. Slowing reproduction reduces the fitness of the virus and three drugs slow reproduction more than a single drug and delay the appearance of drug resistant strains. This is how mutation and selection works with multiple selection pressures.
Now you are simply making up stuff about me? And the reason being what? Look, I'm a physician if it hasn't already been made apparent to you. I have treated many patients with AIDS in my time. I know how these drugs work, and I have repeated the mechanisms several times in this very thread. Pleas stop wasting my and anyone else who is reading this' time and discuss the topic at hand -- your analogy. Triple therapy represents three attacks on a single gene (or two genes when the protease inhibitors are used). This is a very specific type of attack and is not like the typical selection pressures seen in the wild, or I would hope modelled in ev. The proper response to seeing the effect of triple therapy should never be "ooh, three selection pressures and that organism is out", but that strong selection pressures that virtually eliminate replication virtually eliminate replication. If three drugs were all it took to stop evolution, then why do we still have HIV? Why do people on triple therapy still die? And more to the point, how is it that tuberculosis not only still exists but is resurging? the answer is not solely por compliance, though that clearly plays into this. For HIV the situation is much more
complex
Other species may reproduce to fill the niche left by the extinct species but you are not going to get the macroevolution of new species to fill the niche.
What?
There are no selection processes to do this and ev shows that the rate of generation of information is so profoundly slow that nothing can evolve in the time available.
Even if that were the case, which seems to be wrong, but even if that were the case, you do not blame the modelling of the computer program? Are you suggesting that evolutionary change does not occur?
You neglect the host response to disease. Populations that have never been exposed to a particular disease to not mount good host responses to the disease.
OK, this has gone beyond silly, now. I have been harping on host response to disease. Death of the host is a host response to disease is it not? The population effect is the point. People die. When lots of people die the organism tends to die as well. The varieties that are less virulent tend to survive. This is not a matter of a population suddenly creating de novo an immune response, nor is it a matter of the immune response telling the whole story. Rapid death of hosts results in less virulent organisms over time. This has been observed again and again.
The only point you make here is that ineffective selective pressures do no slow reproduction very much.
Yeah, well, it's just blindingly obvious isn't it? Yes, dammit, that has been the whole friggin' point. The number of selection pressures is not the important issue, but the strength of selection pressure. How many times must I repeat the same thing? Weak selective pressures do, however, provide pressure and they elicit change -- that is the very definition of selection pressure.
What you don’t seem to understand that more than one, less severe selection pressures profoundly slows the evolutionary process.
It completely depends on the type of selection pressure. You cannot speak of selection pressures in unqualified terms (as you have been doing). I have never stated that multiple selection pressures do not slow the changes in a particular group, so stop accusing me of what I understand or do not understand. There is no particular reason, however, that there is any substantive change in speed of evolutionary change with multiple weak selection pressures -- see the fitness landscape again.
You and Dr Richard propose that there are thousands of selection pressures on the HIV virus. The mathematics of the fitness optimization of this case is outlandishly impossible. Nothing evolves under these circumstances.
Dr. Richard proposed thousands. I am more conservative in my claims, since I don't consider each immune response gene an independent selection pressure, but that is beside the point.
There were clearly multiple selection pressures on HIV before the introduction of triple therapy. Let's just take the simplest scenario for selection pressures that you have agreed to -- host response in the form of immune reaction, rapid death of host in the early years of the disease, AZT therapy. Yet, under those conditions -- three selection pressures (and I am leaving all the others out) -- the virus mutated and the mutations that got round those selections thrived. Yes, things do evolve under these conditions.
Multiple little effects confound the evolution process, that is what ev shows, that is what Wikipedia explains when talking about fitness landscapes.
No, it's not. How could you so thoroughly misread that passage?
The reason you think my analogy of the use of triple antiviral therapy for the treatment of HIV is inappropriate is that you have no understanding of the mathematics of mutation and selection.
No, it's because your analogy is poor as I have shown you over and over.
People are much more likely to have HIV resistant to three drugs if they are treated with monotherapy.
And this matters how? That isn't the typical treatment now. You cannot shrug this off so easily. Drug resistance still occurs with triple therapy and in patients who are compliant with that therapy. It depends on the type of therapy, though -- more potent therapy provides less opportunity for drug resistance.
Both the mathematical simulation and the real case of the treatment of HIV show how three selection conditions profoundly slow evolution.
Again, no it doesn't. There are many more than three selection conditions working on HIV (repeated for the nth time) and the particular selection pressure represented by triple therapy is relatively unique (repeated for the nth time).
ETA
Does ev try to model multiple selection pressures on a single locus? If so, why? I guess it is an interesting intellectual exercise, but multiple selection pressures on one gene (one locus) is not like multiple selection pressures on one organism.