Evolution Requires Reduction in Genetic Diversity

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Well, at least recognition of a novel trait in a single individual, but as for its source being mutation, no you don't know that. You don't know but what thirty years previously the same trait showed up in a remote area where it soon got interbred back into oblivion. These traits on the other hand are showing up where people have enough interest in such things to treat them as something special.

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Faith, this is a point I've been trying to make. It isn't possible to confuse a simple dominant mutation with a rare combination of genes. The outcomes of breeding are just too different.If you really have a model of genetics that lets you get around that, then let's hear it. As I said before, I'm pretty sure that you don't.

Hardly a surprise. We can't expect her to be honest and admit that she only had a half-baked idea instead of a real argument. Faith can put up an appearance of being reasonable for a while but her mask always vanishes when she starts losing the argument. Indeed, her behaviour suggests to me that she "wins" in-person arguments by ranting until everyone pretends to agree just to get her to go away.

I don't think that there ever was a chance of a productive discussion.Faith knows perfectly well that she needs an answer to mutation. And she doesn't really have one. It should have been the centrepiece of the discussion. But all we got were vague allusions that she wouldn't explain and never really made sense.At best she had something that seemed to make sense to her, but that she never really understood.(And, I will note she has been here to engage in her usual abuse of the message rating system.)

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Which I'm careful to say.

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But remember that the situation for artificial breeds and natural species is different. The breed is defined by its distinctive traits while a species defines its distinctive traits.A species doesn't even need distinctive traits of its own (cryptic species are identical in appearance, but cannot interbreed)

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The fact is you do get stable species and those traits don't mutate or the mutations don't spread in the population because if they did you wouldn't have a species. But you do have species.

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Only true within limits, as I point out above. A species can lose a formerly distinctive trait and it just ceases to be a distinctive trait.

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te or the mutations don't spread in the population because if they did you wouldn't have a species. But you do have species. (Mutations and their spread n the population are an article of faith anyway; the probability of this happening at any rate that you would need it to happen to stop the effects of the NECESSARY reduction in genetic diversity that MUST happen for a species to form, is just about nil. Witness cheetah, witness elephant seal.

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Perhaps you would actually like to show that rather than picking examples that don,t support your claims.

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It can't, increased diversity interferes. Nevertheless you do get true breeds. Therefore you aren't getting the increased diversity you think you are, the mutations you think you are getting.

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Perhaps you would like to show me one of these parent populations that can't breed true. I'm not aware of any or have any reason to believe that any have ever existed.

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The genetic situation is nevertheless the same.

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That is, in general false, and not even relevant since the issue is definition and classification rather than genetics.

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But it is the kind of situation I've been describing all along that is the basis for breeds and subspecies. These require limiting the numbers of individuals, you aren't going to get breeds or species unless you do that and the result is always new traits with less genetic diversity. So of course I'm going to use this kind of example, it's the one I've been using all along. The numbers don't have to be so drastically limited, but they do have to be changed from the parent population so you get the new allele frequencies that bring out the new traits.

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But if you care about the truth you must accept the fact that the situations you choose are exaggerated and represent only a small fraction of the lifetime of a successful species. You cannot simply assume that nothing else matters.But I guess that pretending that your argument is good is more important to you than being honest. How else could you continue such an obvious pretense for years ?

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I'm focused on the ACTIVELY EVOLVING part of a species' life, whatever else matters isn't what I'm talking about.

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Then you claim that not only do you not have an argument against evolution you never tried to produce one ? That you never argued that evolution must run out of variation and end ?Because if you DID try to create such an argument you can't honestly ignore major factors that matter to that argument. Not looking at those factors is not a defence of such an argument, it's an indictment of it, and admission of a fatal and intentional flaw.

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No pretense at all, I'm totally committed to this argument.

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You're "totally committed" to an argument you won't even make a proper go of ?

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I haven't ignored anything that contributes to evolution

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New genetic variation DOES contribute to evolution. Your argument focusses only on times when genetic variation is expected to decrease, ignoring the times when it is expected to recover.

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I've explained what happens to genetic increase.

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So have I. It keeps genetic diversity "topped up" so that evolution can continue indefinitely.If you want to claim otherwise you need more than strange assertions or saying that you aren't interested. And until you do, your argument is dead. Funny how your "total commitment" stops so short of really dealing with this major problem.

Faith, I don't know why you persist with this argument when - after years of trying to get it to work - you still have to evade problems by trying to pretend that your opponents don't understand the argument. Message 175Simply put, even if there is a temporary reduction in genetic diversity in times of heavy selection, such times are the exception - certainly for any successful species. And in the long periods where selection is relaxed there is plenty of opportunity for diversity to recover.

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That's really quite a handicap you are imposing on me here. To my mind I just stated the scientific outline of my argument about what junk DNA is. I believe it clearly fits with the known facts of the percentage of DNA in the genome and offers an alternative explanation that nobody would guess at if I didn't spell it out from time to time when relevant issues come up. Granted, it's a statement of my theory rather than any kind of proof, but you know what, various hypotheses are really all anybody has for junk DNA, so what's wrong with stating mine? I think it helps put my overall argument into perspective.

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I don't think that requiring you to be scientific could be a restriction on any view that you call scientific.But no, your idea that: is pretty silly really. How do genes "die" ? They certainly can't be "killed" just by a bottleneck. How does this hypothesis explain the quantity of junk DNA ? What evidence is there that all junk DNA is "dead" genes ?Really it looks like nonsense made up by somebody with no real understanding at all.

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Then let me try to clarify. I don't mean to be saying that the genes became junk DNA IN the bottleneck but as a result of it due to the loss of so many alleles for so many traits. This should have an effect on the genome over the generations afterward, not immediately.

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So what you are saying is that humans had many times more genes than they do now. But all those extra genes became useless because they were only useful with particular combinations of alleles which were no longer possible.Why would that even be the case ? Why would there be so many genes that are only conditionally useful ? More importantly why do you think that was the case ?Come to that, why even assume that even most junk DNA is pseudogenes ? Only a small proportion is identifiable as such, and I don't think that mutation rates aren't high enough to obliterate that many genes in a few thousand years.

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I'm merely responding to various statements that interpret them as having been lost because they weren't needed, which seems to be a common evolutionist interpretation.

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I thought that was your argument - that they were only useful with alleles of other genes, and those alleles were lost.

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Sometimes sounds positively Lamarckian, as if these mutations increased BECAUSE the gene was slated for junk DNA, like a sort of retirement when no longer needed.

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That's because your interpretation is wrong (ironically that view would be more consistent with your idea - you needed genes to be mutated to the point of being unrecognisable as genes in a few thousand years).Unnecessary DNA is not subject to a higher rate of mutations. It is, however, not subject to selection. Mutating a useful gene to be non-functional would have a significant affect on fitness and should be removed by selection. Mutating a useless, or nearly useless gene to be non-functional would not be removed by selection.So, over generations unnecessary DNA changes faster than that that is needed or useful (at least where the sequence matters). But not because more mutations occur - it's because more are retained in the gene pool.

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But that isn't what I thought. I thought the surviving eight, really the surviving three reproducing couples, had so little genetic diversity left (though they had enough to generate everyone living today, it's relative of course) that when later population splits occurred and some genes were reduced to fixed loci that they'd become vulnerable to further loss and therefore keep adding to the junk DNA. But I finally realized that doesn't happen with population splits in general so there's no reason to expect it to happen as a result even of the Flood bottleneck.

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That doesn't sound like you thought it through. Selection won't "break" a gene - and the gene would have to be actually harmful before selection would even prefer a "broken" version.

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I still think junk DNA is genes that used to do something useful so we are now without those anyway. Are we sickly? Compared to Noah's generation I think we must be. We are certainly vulnerable to quite a collection of maladies from the mild to the lethal that they no doubt weren't.

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If the "junk" is even mostly pseudogenes, we'd have had to have lost a huge number of them - many times what we have now. If the junk was contributing in any other way that is dependent on sequence we'd have still lost a huge amount of functional DNA. And then we have the role of selection which would have favoured the functional versions if they added to fitness. Worse still, it looks like you need a lot of mutation AFTER the junk versions became fixed.So really, your "best" explanation would be to say that Noah and family had most of this assumed functional DNA reduced to junk. The bottleneck is both the easiest place for drift to influence the genome, and relatively long ago. It's still nowhere near a good explanation though.

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I'd direct you to those who call disabled genes junk DNA, which is how I'm using the terms

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The term "junk DNA" is used to refer to any non-functional DNA. Because pseudogenes are (generally) non-functional they are called junk DNA but that is a long way from making the terms synonymous. In fact recognised pseudogenes are only a small proportion of the "junk"So, how did YOU determine that the majority of junk DNA is pseudogenes? It's your idea.Or did you just assume it because you dudn't bother to understand how the term junk DNA is actually used?