Could you perhaps be a lot more specific? A direct quote would be best.
Thatâs nice. Letâs consider an analogy. Suppose I claim that Dr. Smartguy of Prestigious University has proven in his book that the world is flat, and I answer every argument you make for terrestrial sphericity by claiming that he answers that in his book, and you should read it. Are you going to read the book? Are you in any doubt about whether Dr. Smartguy might be correct?
Did that analogy help?
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I think itâs also helpful to extend this analogy to the blog posts claiming to answer critics. We are often told âthis question has been answered in the [book || blog X].â There have been zero empirical answers for why GE assumes the distribution of fitness effects is exclusively deleterious and why natural selection is permanently shut off.
@thoughtful may simply notice the response tend to follow, âmost scientists believe the DFE follows X distribution [insert misquote from Kimura || Keightely || Eyre-Walker]â or âMA experiments in bacteria [which we exclude from GE] do Y [insert misquotes from Dillon || Heilbron]â or âWe cannot measure the DFE so we assume they are overwhelmingly deleterious.â
None of these responses provide evidence for the two fundamental premises of GE: How do you know the mutations are deleterious and how is natural selection always unable to act?
When you look at modern sequencing data and explore the DFE of all mutations, not just deleterious coding variants, itâs clear that these assumptions are not justified.
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Arguments about mutation counts and some people having more and getting selected away donât work because it ignores that some people can have worse mutations that would be selected away. Therefore, VSDM still accumulate.
Also that your argument is just obfuscation and would only lead to extinction earlier, but I may not be understanding your argument correctly.
I basically meant thereâs no mechanism for natural selection to work infinitely. It seems scientists think it cannot break down over time (except perhaps by human intervention).
Well, good Iâm glad you linked this because whatâs below is sort of what I had in my head but didnât know how to articulate. Selection canât work to clear out VDSMs in order to account for / âcreateâ adaptation. Adaptation must happen another way.
Iâd have to finish the book to see if I agree with the section you quoted fully as a good summary of the book. It states the problem of evolution for a Christian audience. But for a scientific audience, Iâd say GE proves there is no mechanism in current theory that works. It is necessary to start with the assumption of a higher power. Whether and when we could go extinct is something to figure out once scientists ditch the current theory and uncover what the biology is really telling us. IMO it appears thereâs a lot left to learn.
While there are essentially no mutations that are strictly neutral, mutations can be so minor in their effects that they are âeffectively neutralâ (Dr Sanford calls them ânearly-neutralâ). Geneticist Motoo Kimura (1924â1994) created a new model where âeffectively neutralâ mutations were a huge proportion of the total. He discovered that these mutations caused a general decline in âfitnessâ over time.Display footnote number:10 This term âfitnessâ is often used in confusing and circular ways, though.Display footnote number:11
Despite this, Kimura never questioned the notion of evolution. He took it on faith that occasional mega-beneficial mutations would cancel out the effect of this gradual decline:
Whether such a small rate of deterioration in fitness constitutes a threat to the survival and welfare of the species (not to the individual) is a moot point, but this will easily be taken care of by adaptive gene substitutions that must occur from time to time (say once every few hundred generations).10
But there is no evidence to justify Kimuraâs wishful speculation. The evidence shows the opposite: given enough time, organisms will eventually succumb to the weight of the damaging mutations that accumulate gradually, and will go extinct.Display footnote number:12 In fact, a paper presented by Sanford and others at a symposium on information at Cornell University demonstrated that lots of such âhigh-impactâ beneficial mutations would actually hasten extinction. They âstrongly interfere with selection for or against all low-impact mutationsâ, which makes the problem of genetic entropy worse.Display footnote number:13
Correct. Natural selection will only work so long as there is reproduction.
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Heh. So youâre going to ignore the huge point GE is based on the falsehood all species were specially created only 6000 years ago and just blindly C&P the already discredited science-free nonsense. Yet you still wonder why people think you arenât even trying to understand.
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You would be dead wrong as all the empirical evidence you keep ignoring shows. Relying on a Creationist website which only references other nonsense Creationist publications is a loser from the start.
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Iâm sorry to say but no, you donât appear to be understanding my argument at all. You are basically just repeating the basic premise of GE with all itâs implicit assumptions. I am arguing that those assumptions are wrong, with evidence. That the DFE will shift increasingly towards more deleterious as absolute fitness increases, so when absolute fitness is high we get a DFE more like Sanford imagines it, but if absolute fitness were to drop further down, the DFE would shift increasingly back towards more equal. That is what real empirical evidence shows happens.
Hereâs a series of figures I have drawn to explain the basic principle.
At very low absolute fitness, the distribution of fitness-effects of mutations is much closer to equal. Though as depicted here it doesnât have to strictly be equal, there can still be a significant deleterious bias. For example with 70% of mutations being deleterious, and 30% being beneficial.
At higher fitness, beneficial mutations have smaller effects and are fewer in total numbers. The ratio of deleterious to beneficial shifts further towards deleterious:
At very high absolute fitness many attributes of the organism have found local optima, if not the global one, and so beneficial mutations have become very rare if not completely exhausted for many âpartsâ of the organism. DNA binding proteins are highly specific, many enzymes have very high activity, the distribution is starting to look more like what Sanford thinks it is.
Sanfordâs argument requires that this last figure is how the DFE has to basically always look, that this picture is âfixedâ and the absolute fitness of the organism has essentially no effect on the DFE. This is empirically false. As in we can measure it to be false in experiments designed very carefully to find out how absolute fitness levels affect the DFE.
That is the basic principle of my argument.
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Those âserious population geneticistsâ disagree with you.
No. But I have to admit that I may have misinterpreted what @PDPrice said about this subject.
No doubt about this.
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Gil, does Sanfordâs use of a courtroom metaphor with himself as judge not provide a strong indication that this is not science?
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In addition to the excellent points from @Rumraket, also realize that most traits are controlled by multiple loci. For such traits, a particular allele may increase the trait value by 0.01% of the optimal value, while another might decrease it by 0.01%. Having both alleles or neither would cause no change in fitness, while having only one or the other would cause a VSD change in fitness. Accumulation of such mutations wouldnât alter average fitness, but would increase variability of phenotypic expression, actually increasing the capacity of the population to adapt to small changes in environmental conditions.
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I agree, he says it, more or less: if species are not going extinct, Darwinian theory is false. But that isnât true. What really true is this: if species are not going extinct, his particular model of evolution, including all the various parameters he assumes, is false. But note that he thinks species are indeed going extinct, so Darwinian theory (or his model) must be true, and he explains it on that very page by concluding that the world is 6000 years old.
OK, Iâll rephrase: either his model of evolution is false or deep time is false. Which do we have more evidence for? Well, we have no evidence supporting his model of evolution, and vast amounts of evidence for deep time. And now weâre done.
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Iâll have to finish the book to see if @rumraket argument is addressed, but it seems to be a theoretical argument that is a combination of the two discussed in chapter 7. So Iâll need to study the linked papers to see what they proved.
But in regards to your argument, if the phenotypic expression doesnât affect fitness, then I donât see how it has anything to do with natural selection. And if it helps them adapt then wouldnât they be beneficial? So this just seems to be the obfuscation Sanford was referring to.
My favorite scientific argument - one or two branches of science must be correct, therefore no evidence can correct a related branch, no matter how many holes any of them accumulates.
Letâs please ignore the fact that Darwin based his theory on the newer idea of deep time. Would he have proposed it had not that happened? Letâs please ignore that the Big Bang has some major problems.
If you were attempting to paraphrase my argument, you did a poor job of it.
No, he did not. Where did you get that idea?
How is the Big Bang relevant? You arenât making any sense.
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Maybe I overstated. It influenced him, at minimum. Iâd have to study the history more to know how much Darwin's Tree and Deep Time - Scientific American Blog Network
âVast amounts of evidence for deep timeâ? What else are you referring to that doesnât make arguments based on the same set of assumptions?
It does affect fitness. You can move away from a fitness peak for a continuous variable in two directions, and mutations are equally likely to move away in one direction as the other. So the aggregate impact of accumulating these mutations is that the average phenotype will be the same, but the variation will be larger.
The capacity to adapt to future conditions is not beneficial now.
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Well of course it did. Darwin read Lyell and studied geology on the Beagle. He knew all about deep time. It just wasnât the basis of his theory. (Two theories, actually: natural selection and divergence.)
You know nothing about the evidence for deep time. Darwin, for example, knew nothing of radiometric dating. Nor is the Big Bang relevant to the deep time weâre talking about, which is the age of the earth and life.
There is of course astronomical data. Incidentally, the one-way speed of light doesnât deal with things like supernova remnants that take a long time to assume their observed forms; you would have to assume that the remnant was created in that state, implying a supernova that never happened. If you suppose that a remnant implies a supernova, some of them are several times older than you think the universe is.
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