Doesn’t Genetic Entropy bar the possibility of even micro-evolution?
No, not at all. It allows for neutral and nearly neutral evolution, and it even allows for both purifying and positive selection. It just demands that population fitness continually decreases, with all species approaching mutational meltdown and extinction. But until that extinction happens, microevolution still goes on. In fact, GE is microevolution.
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It could even allow for speciation (and thus macroevolution by some definitions), as isolated population’s reproductive preferences, or compatibility, divergently decays into incompatibility.
Further, GE has nothing to say about evolution involving selectable mutations.
This is the opposite of “genetic entropy”, at least as its most commonly used. Sanford pulls this bait-and-switch in his book, without explaining how a populations suffering declining fitness suddenly due to an overwhelming number of mutations suddenly starts suffering the ill effects of inbreeding and homozygosity. Too much diversity, or too little? Pick one, GE proponents.
I had no idea that “genetic entropy” was commonly used at all. Or did you mean “mutational meltdown”? I was just talking about the (supposed) cumulative effect of lots of nearly neutral mutations, eventually producing a genetic load so large that it results in extinction. No selection happens in this scenario, as there is no significant genetic variance in the population.
And of course the fact that we don’t see the human population declining would seem to argue against that notion.
I mean “mutational meltdown”, which I’ve always understood, and seen used, to mean “extinction vortex” - small population, drift, inbreeding, rinse and repeat. Genetically, that and GE are opposites - too much diversity (in the form of harmful mutations) vs. too little (and the resulting recessive phenotypes).
I think Sanford is using the term in the vague sense of a reduction of population fitness leading to extinction, by whatever mechanism. If that’s an inappropriate usage, never mind. Dammit, Jim, I’m a systematist, not a population geneticist.
Yup. That’s what he does. Which has the effect of pointing out specific flaws tricky, because GE proponents can play “well that’s not really what we mean” 'till the cows come home.
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According to M. Lynch, the fitness of the human population is declining due to an increase in mutation load.
No, the fitness will supposedly decline in the future, and has not been declining so far due to changes in the environment, i.e. medical science. This argues against Sanford’s GE, because that has supposedly been going on from the beginning, not just in the last hundred years or so. Note also that he’s talking about mutations of large effect, not nearly neutral ones. Totally different cases.
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Has @PDPrice offered any comments on this laboratory experiment at Harvard Medical school?
Does he think bacteria’s ability to quickly evolve to populate heavily toxic environments is still representing Genetic Entropy?
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Déjà-vu
Did he ever say that it did? This would not be consistent with the main idea of GE, which is that nearly neutral mutations accumulate. The mutations causing antibiotic resistance are usually subject to positive selection, though some may be neutral until combined with other mutations.
I don’t believe @PDPrice has commented on this experiment either pro or con. But I’m certainly more likely to keep bringing it up the longer he goes without discussing it’s supposed irrelevance.
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Do any other scientists want to chime in with their critiques of GE here, beyond what I already listed in my comment? Do any scientists want to suggest that somehow I’ve misunderstood their critiques? (Not that they disagree with my response, but that I didn’t understand their objection properly)
Several people have already done this. Didn’t you notice? #2 in particular is an unrecognizable caricature of something someone might have said, but it’s hard to tell because it’s, as I said, unrecognizable.
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Explain to me the right way to frame this objection, then. What is the relationship between GE and Junk DNA, in a single sentence? (ok, you can use multiple sentences)
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That’s already been done, and you haven’t AFAICT updated your list to include the additional objections (e.g. ancient life).
Also been done.
If you updated your original list, we’d be able to see whether you had acknowledged and understood the new/amended critiques. But asking without having done that seems liable to just generate a lot of unnecessary and pointless repetition.
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Hard to say. It’s so garbled that it’s not clear what objection you refer to.
First you confuse non-coding DNA with junk DNA, and then you endorse the original claims of ENCODE, which even ENCODE has backed down from. I don’t even see what the criticism of GE is supposed to be in that.
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