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Author | Topic: Iconic Peppered Moth - gene mutation found | |||||||||||||||||||||||||||||||
Faith  Suspended Member (Idle past 1469 days) Posts: 35298 From: Nevada, USA Joined: |
There was never any more than ordinary microevolution brought about by natural selection to the peppered moths, and making the change the result of a mutation instead of ordinary microevolution raises the question: how is it that a mutation so suited to the needs of the creature just happened to come along at the right time? Aren't mutations random accidents in DNA replication, and very rare and so on? Or is the ToE now reverting to Lamarckianism?
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Faith  Suspended Member (Idle past 1469 days) Posts: 35298 From: Nevada, USA Joined: |
There are alleles for brown eyes and blue eyes, no difficulty having alleles for black moths and white moths. It's just weird that a very particular accident in replication came along at JUST the right time...
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Faith  Suspended Member (Idle past 1469 days) Posts: 35298 From: Nevada, USA Joined: |
We can also add that the dark species was unknown prior to 1811, and that the gene for black moths is dominant. This is a new allele, and clearly a mutation. Even a dominant can more or less disappear in a large population where the recessive is strongly selected. That's how you can get a predominantly blue-eyed population. The dominant could eventually die out or it could remain here and there in the population in the heterozygous form, the recessives always being so much more numerous they are an extreme rarity. Similarly the very rare heterozygous black moths would not survive long, but probably not completely die out, and then would be selected against the sooty background of the Industrial Revolution, begin pairing up and proliferate as the whites were picked off by predators. Then the recessive whites would become rare, but still occasionally pair up to be selected when things got cleaned up.
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Faith  Suspended Member (Idle past 1469 days) Posts: 35298 From: Nevada, USA Joined: |
So, no, your hypothesis does not fit the evidence. But thanks for acknowledging some other effect other than isolation for changing the prevalence of phenotypes and genotypes. You mean new gene frequencies brought about by selection? But that's all the same thing I've been talking about. In this case the selected black moth has the higher gene frequency and will proliferate, bringing about the new population. Same process exactly, while losing the allele for the white moths.
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Faith  Suspended Member (Idle past 1469 days) Posts: 35298 From: Nevada, USA Joined: |
The only way you get dominant and recessive alleles of the same gene is through mutations. The reason that they are dominant and recessive is due to DNA sequence differences brought on by mutations. That's pure theory, not something known by observation. If genetic material was built in from the Creation it included all the dominant and recessive forms of alleles and their combinations just as Mendel spelled them out. And it's bizarre to think you NEED mutations, since if you did get them as reliably as claimed, they would act EXACTLY like the built-in alleles would act anyway. Edited by Faith, : No reason given.
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Faith  Suspended Member (Idle past 1469 days) Posts: 35298 From: Nevada, USA Joined: |
Where is there any evidence that the mutation only came about when it was needed? In Tangle's original post where he quoted the date for its appearance in the late 1800s at the height of the Industrial Revolution.
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Faith  Suspended Member (Idle past 1469 days) Posts: 35298 From: Nevada, USA Joined: |
I was talking about the rise of the black moths due to the blackened tree trunks.
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Faith  Suspended Member (Idle past 1469 days) Posts: 35298 From: Nevada, USA Joined: |
The thing Faith needs to remember is that it really is a multipart system. Mutations causing dark moths may well have been happening all along but before the soot phase of the industrial revolution they were simply dinner. It was only when the selection pressure changed that the dark moths had an advantage. It was selection that determined this particular mutation got preserved. Any earlier examples of a similar mutation would have just been putting food on the table. If you'd been following my posts you would know that this is exactly what I said would be the situation if the black moth alleles were built in. While the whites were selected the blacks would show up from time to time in heterozygous form and be picked off by predators. It was only when the whites started getting picked off instead (selected against) that the blacks could start to multiply. Same thing whether built in or mutated. If a black mutation occurred during the white advantage and managed to survive, then it would fare exactly as it would if it was a built in allele -- its numbers would stay small because of being constantly picked off by predators. However, if it did arise during the time the whites had the advantage it would have a very low probability of surviving at all. But you even have black moth mutations "happening all along" as if it's that common an event that the same locus has the same mutation over and over again? Is mutation ever described in such terms? If the timing is that exquisite that it has to happen either over and over again, or just when the conditions for its selection are optimum, is this really mutation, meaning a random accident of replication? What are the odds? Edited by Faith, : No reason given.
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Faith  Suspended Member (Idle past 1469 days) Posts: 35298 From: Nevada, USA Joined: |
I wasn't talking about the single mutation of the peppered moths but responding to Taq's generalization about mutations in general.
However, I'll respond to this:
The peppered moth's evolution from white to black and back to white again is pure observation. That's how we know about it - it is documented. The mechanism that allows the selective survival of black moths over white moths has been observed - the darkening of the trees on which the moths rest during the day leaving them open to predation against the newly black trunks. The predation process was reversed when the trees were no longer black. Observed and documented.
That much is common knowledge, and quite easily explained in terms of a built-in allele for the black moth. Mutation is in fact harder to explain. See my post to jar above. There is something very very weird about the idea that it was a mutation instead of built-in for the reasons I give there. You either need many same or similar mutations at the same locus to counteract the constant loss to predation, which doesn't fit with the general observations of mutations as random accidents of replication, or you have to count on one mutation surviving against ridiculous odds, or showing up so exactly at the right time that only a teleological mechanism could explain it. Not what the ToE normally has in mind. There has to be something wrong with the science that supposedly "observed" this mutation. Edited by Faith, : No reason given. Edited by Faith, : No reason given. Edited by Faith, : No reason given. Edited by Faith, : No reason given. Edited by Faith, : No reason given. Edited by Faith, : No reason given. Edited by Faith, : No reason given.
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Faith  Suspended Member (Idle past 1469 days) Posts: 35298 From: Nevada, USA Joined: |
Faith writes: If you'd been following my posts you would know that this is exactly what I said would be the situation if the black moth alleles were built in. While the whites were selected the blacks would show up from time to time in heterozygous form and be picked off by predators. It was only when the whites started getting picked off instead (selected against) that the blacks could start to multiply. But Faith you have provided no evidence of any built in conditions and all the evidence shows that is NOT the case nor have you provided a model, process, mechanism, procedure or thingamabob that would explain how the genes would get transferred when the critter gets eaten immediately. Of course you've changed the subject. How predictable. How's about taking a break from your rote response long enough to grant that I made exactly the same point you claimed I didn't understand, that IF the alleles are built in they would follow exactly the pattern you claim for mutations -- and a lot more efficiently for the reasons I gave that mutations are at a disadvantage. And showing that mutations are a crock ought to count for something in favor of my point of view and I've certainly shown they are a crock in this and other posts. You're the master of blather. Try acknowledging the very simple obvious point I made please. Edited by Faith, : No reason given.
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Faith  Suspended Member (Idle past 1469 days) Posts: 35298 From: Nevada, USA Joined: |
Interesting of course that you don't even consider what I actually said about why mutations are harder to explain. Try it.
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Faith  Suspended Member (Idle past 1469 days) Posts: 35298 From: Nevada, USA Joined: |
This is more or less incomprehensible. What you actually need is for the mutation to show up and be favored by natural selection. Mutations occur, and natural selection would have favored this one. Any questions? It would have favored it only at precisely exactly the right time for it to fit into the newly blackened environment. Otherwise it would have been eaten. Do follow the argument. Really. Make an effort to follow the argument. I don't know why it wasn't noticed but it must have arisen earlier, because it makes less sense for it to have arisen "just in time" to be selected. Most mutations are said to have been present some time before they get selected anyway. It's just that this situation is peculiarly high pressure -- get selected NOW or die! Edited by Faith, : No reason given.
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Faith  Suspended Member (Idle past 1469 days) Posts: 35298 From: Nevada, USA Joined: |
I haven't said it can't happen. But exploring the consequences of different scenarios makes it highly improbable this was a mutation. Unless it was a very old mutation that kept popping up from time to time anyway, most of the time to be eaten by birds, many years before being selected. In which case it might as well be a built-in allele anyway. Righto, I don't trust this kind of science.
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Faith  Suspended Member (Idle past 1469 days) Posts: 35298 From: Nevada, USA Joined: |
If you'd been following my posts you would know that this is exactly what I said would be the situation if the black moth alleles were built in. While the whites were selected the blacks would show up from time to time in heterozygous form and be picked off by predators. It was only when the whites started getting picked off instead (selected against) that the blacks could start to multiply. But if this is a dominant allele the black moths wouldn't show up 'from time to time'. They would, of necessity, need to be present in every single generation. But in very small numbers, because they WOULD be picked off by predators. Not all that show up but most. And all I was doing was saying exactly what jar had already said about what would have had to happen, only in my scenario it's not a mutation, just a naturally-occurring alternate form of the gene. According to the study, however, it's not a gene that normally codes for color. But my point was that it shouldn't matter if it's a mutation or a built-in variation, it can only arise sporadically and couldn't survive in great numbers. If it survived at all.
And they would be selected against - a dominant allele which is selected against will vanish from a population much more quickly than a recessive one, since any individual carrying the allele is subject to whatever causes the negative selection pressure (in this case being easier to eat). Right, but is it more unlikely that the allele would not completely disappear but remain and show up rarely, than a mutation simply showing up just in time to be selected against the black trees? It seems to me every possible scenario has some problem attached to it.
But you even have black moth mutations "happening all along" as if it's that common an event that the same locus has the same mutation over and over again? Is mutation ever described in such terms? You don't need the exact same mutation. I imagine something like being black can be acheived in a huge diversity of ways. Well the study pinned it down to a specific change in a specific gene at a specific time -- the year 1819 -- and a gene not normally associated with color.
For a similar example in humans, we can see that Europeans and east Asians have light skin due to different mutations. In both cases people moved to higher latitudes where lighter skin would be beneficial, and in both cases a mutation arose which caused lighter skin, but it was not the same in each case. The specific mutation selected for was the one which happened to come along at the right time. Then how is this "mutation" if it "comes along at the right time?" Is mutation a random accident of replication or is it an inevitable requirement of genetics? Which is it???? There is absolutely no reason why skin color has to be the result of a mutation anyway. There is a huge range of skin color built into the human genome going back to Adam and Eve.
The same is true of lactase persistence in humans, northern Europeans and east Africans both evolved lactase persistence independently and the genetic basis is different in each case. If you weren't all expecting to find mutations to explain everything, I wonder if you would find them.
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Faith  Suspended Member (Idle past 1469 days) Posts: 35298 From: Nevada, USA Joined: |
I kept thinking of the pocket mice through this whole discussion too. Same situation.
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