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Author | Topic: Is there any proof of beneficial mutations? | |||||||||||||||||||||||||||||||||
Wounded King Member Posts: 4149 From: Cincinnati, Ohio, USA Joined: |
I think you would have to define 'true multicellularity' more clearly for this to be sufficient. One of the distinctions commonly made between multicellular organisms and simpler colonial organisms is a distinct division of cells between reproducing and non-reproducing types. i.e. the establishment of specialised germ line cells. In Volvox carteri for instances there are a few (~16) germ line cells supported by ~2000 somatic cells.
TTFN, WK
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Wounded King Member Posts: 4149 From: Cincinnati, Ohio, USA Joined: |
Although, I'll note my disagreement with AZPaul3 when he says "a colony of bacteria will often quicken their individual mutation rates in hopes of hitting on some useful mutation before the colony dies out completely". I do not think there is any particularly credible reason to think the increase in mutation rates is adaptive rather than simply a consequence of the circumstances. I'm not sure what distinction you are making. Surely the point is that such mutations are the source of adaptive mutations which has been shown. The fact that they are induced as a response to stress seems irrelevant.
1. The repair of DNA is an extremely energy intensive, and on-going, process. At times of stress organisms may divert some of the energy invested in maintaining the health of DNA into more immediately vital functions. In the research AZPaul3 linked to the bacteria activated an error prone polymerase in response to starvation. I think claiming that an error prone polymerase is beneficial because it uses less energy is a pretty substantial assumption. In fact there is some reason to believe that some error prone polymerases actually require more energy because incorporating a mismatched base into a pair requires more energy since they lack the affinity that complementary pyrimidines and purines have. I can see the argument you are making working if all that happened was that some DNA repair processes were turned off under stress but instead additional DNA repair enzymes, which happen to be error prone polymerases, are produced in 10 times the normal amount (in the case of PolIV)(Fuchs et al., 2004).
2. Many stressors will themselves directly damage DNA. This is often why they're stressors at all. This is a fair point but there is substantial research showing that PolIV introduces mutations in the absence of DNA damage. You can't simply ascribe it all to environmental factors. Estimates have been made that as much as 50% of stationary phase mutations in E. coli are due to PolIV. TTFN, WK Edited by Wounded King, : No reason given.
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Wounded King Member Posts: 4149 From: Cincinnati, Ohio, USA Joined: |
Any evidence suggesting that this is actually the result of a mutation?
TTFN, WK
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Wounded King Member Posts: 4149 From: Cincinnati, Ohio, USA Joined: |
Hi frako,
As others have pointed out, I'm not a creationist nor indeed any sort of theist. Tooth agenesis is a complicated developmental issue and there is no clear genetic basis for what causes some wisdom teeth not to develop. Some factors have been identified, Pax9 (Pereira et al., 2006), which seem to show a strong association with third molar agenesis but this is by no means the sole determining factor nor is Pax9' s role entirely settled. I was just suggesting that a) Schraf's condition may be inherited, in which case a creationist is likely to dismiss it as being already existent genetic variation and certainly not a de novo mutation. or b) Possibly Schraf's missing wisdom teeth are, as Huntard suggests, an environmentally caused variation rather than one with a genetic basis, which unless she has had her genome analysed is not something Shcraf can really rule out. *ABE* I forgot a third point, c) Even given that Schraf's lack of lower wisdom teeth is the result of a novel mutation there is no evidence that it is beneficial in evolutionary terms simply because Schraf prefers not to undergo multiple painful dental surgeries. Certainly untreated impacted wisdom teeth can cause death so I can see a 'just so' rationale for it being beneficial, but this is far from being a certitude. */ABE* TTFN, WK Edited by Wounded King, : Added point c.
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Wounded King Member Posts: 4149 From: Cincinnati, Ohio, USA Joined:
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There are a number of mutations which have been identified as conferring some resistance to HIV-1 infection and/or AIDS progression, one is a 32bp deletion in the gene for the CCR5 chemokine receptor protein which confers almost complete resistance to infection in homozygotes (Struyf, 2000) and slows progression in heterozygotes, other chemokine receptor variants also retard progression and some variants have been identified which seem to accelerate progression (Rana et al.,1997; Parczewski et al., 2009 PDF). The molecular basis for many of these is well understood and centers around the way the HIV virus utilises receptors of the immune cells to infect the cell (Venkatesan et al., 2002).
My understanding is that there is not even a clear definition of what Aids actually is, so I think to say that one mutation can make someone resistant to something we can't define seems a little unclear. I think your understanding is wrong, try the scientific literature there really is quite a lot about HIV and AIDS. TTFN, WK
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Wounded King Member Posts: 4149 From: Cincinnati, Ohio, USA Joined: |
I am saying that there are people whose job it is to study these diseases who say that the links between Aids and HIV are not so simply defined Well so far you have given one mathematician who did a PhD, had a handful of publications and then apparently gave up a career in science for a career in selling books to AIDs I find it to be imprecise and misleading when Wounded King or Mr. Jack make these kind of blanket statements that the disease is perfectly understood. Since we are talking about being misleading maybe you can show where either Mr. Jack or myself said that it was perfectly understood? TTFN, WK
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Wounded King Member Posts: 4149 From: Cincinnati, Ohio, USA Joined: |
I think your score is a little off, how about the 4 peer reviewed papers from the scientific literature I already cited?
Why don't you respond to those before I have to respond to a whole slew of assertions from the first aids denialist you glommed onto from google. I know that creationists/IDists prefer argument by cut and paste but still. As to being off topic, I don't see where your quote said anything about the evolution of resistance. Is this you starting Minemooseus topic drift game early? You sly dog. TTFN, WK
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Wounded King Member Posts: 4149 From: Cincinnati, Ohio, USA Joined: |
Like others have said, the fact that there is a "dispute" here doesn't do anything to buttress the underlying claims of evolution defenders. I wouldn't think so since buttressing a claim would be to support it, perhaps the seige metaphor you were looking for was 'undermine'. TTFN, WK
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Wounded King Member Posts: 4149 From: Cincinnati, Ohio, USA Joined: |
Don't forget retroviruses- They are currently believed is how new innovations occur and because they are involved in regulatory functions that they can modify bone structure, scales into feathers, etc. The fact that they are species specific and target a specific chromosome in alteration is important. This sounds pretty confused, could you give us some links to where you are getting this information from? Or a much clearer explanation of what you are saying?
Creation vs evolution debate will continue because retroviruses can be viewed either way. No, the debate will continue because no matter what the evidence the creationists will persist is viewing it in such a way that it can be shoehorned into their belief system making up new ad hoc explanation as they go along. Just look at any of the threads about genetic information to see the frequent goalpost moving that is characteristic of these discussions. TTFN, WK
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