That ironically fits in well with Behe’s latest article over at ENV:
Here’s How to Tell if Scientists Are Exaggerating by Michael Behe
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I think Behe has realized he can make a tidy second income from telling the illiterati what they want to hear. I have to believe that’s a strong impetus for some of the garbage books he has produced.
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Hardly. T_aquaticus wonders how it is possible to explain how less fit alleles outcompete fitter alleles. The answer is genetic drift. Then the conversation devolved because “scientists” here don’t understand genetic drift.
Hardly. Here’s what he wrote:
Your characterization is simply false.
That’s one of multiple answers. So, can Behe explain it given his scientifically illiterate fixation on Darwin?
Do you know the others?
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It doesn’t follow that genetic drift only applies to neutral alleles. Neutral alleles will “drift” but both “beneficial” and “deleterious” alleles are also susceptible to sampling error. For example, a beneficial allele can be lost and a deleterious allele can be retained and spread.
If neutral alleles can drift why can’t deleterious alleles also drift? Do you have a reason?
Your claim that drift is non-Darwinian is false.
This is false.
And “nearly neutral” has nothing to do with it.
No, T_aquaticus clearly is asserting that genetic drift does not apply to deleterious mutations.
Methinks Mung’s obsessions deserve to be moved to a new thread.
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Mung is right here and T_aquaticus made an error. Drift certainly applies to mutations of all fitness effects. And it is entirely possible for a deleterious allele to fix against a backdrop of higher fitness alleles under a variety of circumstances.
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Why don’t you just explain random genetic drift and we can all move on?
What does or doesn’t make sense to you has no bearing on the accuracy of scientific theories.
The probability of beneficial or detrimental alleles spreading through a population is different than the same probabilities for neutral alleles. Genetic drift is a special case where there is a lack of selective pressure.
Neutral mutations all have the same probability of reaching fixation which is about 1/(2N) where N is the population size. Deleterious mutations have less of a probability of reaching fixation than neutral mutations while beneficial mutations have a greater chance. This is also reflected in Ka/Ks ratios.
No. Random genetic drift operates in any finite population but it’s effects are greater in small populations.
Please listen to Rumraket.
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How is that relevant to what I said?
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That’s some of it. There’s more. Note that just because you cited something is no indication that you understood it, as demonstrated with Behe above.
That wasn’t the characterization to which I was referring, but I think you know that.
What you said was mistaken and I explained why it was mistaken. That’s how it was relevant.
This is a mistaken understanding of drift. Drift is present regardless of whether there is a lack of selective pressure. It’s not a “special case” of anything.
That assumes independent assortment, though, correct? I think that is what Mung is getting at.
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Fair enough. What I mean to say is that neutral evolution proceeds by just genetic drift while beneficial and deleterious mutations are under selection. Again, this goes back to Behe’s apparent claim that genomes are continually increasing in detrimental mutations which makes no sense.
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Actually you can have neutral evolution under purifying selection. Mean fitness can be kept at some level because purifying selection is weeding out deleterious mutations, but allowing nearly neutral mutations to accumulate. This in large part explains the drifting apart of DNA sequences encoding functional orthologous proteins in different species.
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