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Author Topic:   Is there any proof of beneficial mutations?
Dogmafood
Member (Idle past 348 days)
Posts: 1815
From: Ontario Canada
Joined: 08-04-2010


Message 46 of 166 (579798)
09-06-2010 1:56 AM


Christ, you people are smart! I'd better get mutating.

  
Dr Jack
Member
Posts: 3514
From: Immigrant in the land of Deutsch
Joined: 07-14-2003
Member Rating: 8.7


Message 47 of 166 (579809)
09-06-2010 5:11 AM
Reply to: Message 41 by Dogmafood
09-06-2010 1:34 AM


Re: Cause of mutation?
I dont mean to imply consciousness but does this not suggest it? Why should mutations increase when the organism is under stress?
I can think of four reasons off the top of my head:
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.
2. Many stressors will themselves directly damage DNA. This is often why they're stressors at all.
3. Stressors that occur during mitosis can disrupt the process, resulting in copy errors, replication slippage (causing duplication or deletion errors) or the misseperation of plasmids, and proteins into the two daughter cells.
4. Organisms will often respond to stress by commencing the synthesis of many new proteins. In order for genes to be expressed, the DNA coding them has to be unwound, and the strands separated so that the antisense strand can be accessed for transcription. During these processes the DNA is more vulnerable to damage than usual.
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.

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Replies to this message:
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nator
Member (Idle past 2169 days)
Posts: 12961
From: Ann Arbor
Joined: 12-09-2001


Message 48 of 166 (579826)
09-06-2010 8:28 AM
Reply to: Message 1 by Xstar
09-03-2010 8:06 PM


I have searched high and low to find any evidence supporting a beneficial mutation.
I have one.
I have a mutation that prevented my lower wisdom teeth from forming. I have needed extractions in my upper jaw before my wisdom teeth (upper only) came in because all of my teeth didn't fit, so I think the same woud have been needed for my lower jaw had the lower wisdom teeth existed.

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Replies to this message:
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Wounded King
Member
Posts: 4149
From: Cincinnati, Ohio, USA
Joined: 04-09-2003


Message 49 of 166 (579839)
09-06-2010 9:45 AM
Reply to: Message 47 by Dr Jack
09-06-2010 5:11 AM


Re: Cause of mutation?
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: 04-09-2003


Message 50 of 166 (579840)
09-06-2010 9:47 AM
Reply to: Message 48 by nator
09-06-2010 8:28 AM


Any evidence suggesting that this is actually the result of a mutation?
TTFN,
WK

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Replies to this message:
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 Message 55 by nator, posted 09-06-2010 7:41 PM Wounded King has not replied

  
frako
Member (Idle past 305 days)
Posts: 2932
From: slovenija
Joined: 09-04-2010


Message 51 of 166 (579842)
09-06-2010 9:51 AM
Reply to: Message 50 by Wounded King
09-06-2010 9:47 AM


rofl well if a gen changes in a dna strand its called mutation. or you can go back to the bible and think to yourself god willed that gen to change. and il say well my god willed a undetectable pink unicorn into being that unicorn then crated your god who created everything then willed that gen to change.

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Huntard
Member (Idle past 2295 days)
Posts: 2870
From: Limburg, The Netherlands
Joined: 09-02-2008


Message 52 of 166 (579844)
09-06-2010 10:00 AM
Reply to: Message 51 by frako
09-06-2010 9:51 AM


frako writes:
rofl well if a gen changes in a dna strand its called mutation.
Yes, Wounded King is aware of that. In fact, it doesn't even have to be an entire gene.
or you can go back to the bible and think to yourself god willed that gen to change.
Wounded King is not a bible thumper.
and il say well my god willed a undetectable pink unicorn into being that unicorn then crated your god who created everything then willed that gen to change.
You could, you would be wrong though.
What Wounded King is saying is that he wants to know if Nator having no bottom wisdom teeth is due to a mutation in her genes, or due to some other source, like something in the developmetn stage (I imagine).

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Blue Jay
Member (Idle past 2697 days)
Posts: 2843
From: You couldn't pronounce it with your mouthparts
Joined: 02-04-2008


Message 53 of 166 (579923)
09-06-2010 3:53 PM
Reply to: Message 51 by frako
09-06-2010 9:51 AM


Hi, Frako.
Welcome to EvC!
All it takes for you to think someone is a Bible-thumping creationist is for them to ask whether or not a particular trait is due to mutation?
Not everybody who challenges an evolutionist's claim is a Bible-thumper, or even a creationist, for that matter.
Many evolutionists are in the habit of correcting other evolutionists when they think correction is required. You should really develop a habit of gathering more data before jumping to conclusions.

-Bluejay (a.k.a. Mantis, Thylacosmilus)
Darwin loves you.

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Wounded King
Member
Posts: 4149
From: Cincinnati, Ohio, USA
Joined: 04-09-2003


Message 54 of 166 (579931)
09-06-2010 5:30 PM
Reply to: Message 51 by frako
09-06-2010 9:51 AM


Genetic basis of third molar agenesis
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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nator
Member (Idle past 2169 days)
Posts: 12961
From: Ann Arbor
Joined: 12-09-2001


Message 55 of 166 (579941)
09-06-2010 7:41 PM
Reply to: Message 50 by Wounded King
09-06-2010 9:47 AM


I don't know for sure in my case, since my DNA has not been sequenced, but missing third molars are, apparently, quite common.
From the Dental Genetics Group website:
Page not found (404) | University of Helsinki
Congenitally missing teeth
Missing of one or more teeth is perhaps our most common congenital malformation. More than 20 % of us lack one or more wisdom teeth (third molars). More than five percent of us lack one or more second premolars or upper second (lateral) incisors. Lack of a large amount of teeth, though, is much more rare.

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crashfrog
Member (Idle past 1467 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 56 of 166 (579942)
09-06-2010 7:43 PM
Reply to: Message 54 by Wounded King
09-06-2010 5:30 PM


Re: Genetic basis of third molar agenesis
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.
I would guess it depends. How many grandchildren does she have?

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Coyote
Member (Idle past 2106 days)
Posts: 6117
Joined: 01-12-2008


Message 57 of 166 (579947)
09-06-2010 8:06 PM
Reply to: Message 54 by Wounded King
09-06-2010 5:30 PM


Re: Genetic basis of third molar agenesis
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.
The lack of third molars can be beneficial in certain circumstances.
However, in most societies around the world, and for most of history, I doubt that they would have been so much of a problem.
Normal dental wear, eating normal prehistoric foods, causes some flexing of the teeth in the gums and this causes what is called interproximal wear. When the teeth are used properly this wear is just enough to reduce the space between adjacent teeth slightly due to abrasion, and through mesial drift the teeth move forward slightly. This allows enough room for the third molar to fit.
With our modern diets of soft processed foods, the interproximal wear is insufficient, and there is often not enough room for the third molars.
I suspect, based on the percentage of people missing third molars, that there was a mutation somewhere along the line but that there was insufficient selection pressure to either eliminate that mutation or to cause it to spread to all members of the population.

Religious belief does not constitute scientific evidence, nor does it convey scientific knowledge.

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Coragyps
Member (Idle past 734 days)
Posts: 5553
From: Snyder, Texas, USA
Joined: 11-12-2002


Message 58 of 166 (579948)
09-06-2010 8:16 PM


This recent discussion irritates those of us who grew six wisdom teeth.

Replies to this message:
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jar
Member (Idle past 394 days)
Posts: 34026
From: Texas!!
Joined: 04-20-2004


Message 59 of 166 (579949)
09-06-2010 8:17 PM
Reply to: Message 58 by Coragyps
09-06-2010 8:16 PM


So did the damn wisdom teeth.

Anyone so limited that they can only spell a word one way is severely handicapped!

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Omnivorous
Member
Posts: 3978
From: Adirondackia
Joined: 07-21-2005
Member Rating: 7.3


Message 60 of 166 (579956)
09-06-2010 10:17 PM
Reply to: Message 51 by frako
09-06-2010 9:51 AM


He blinded you with science.
Don't get discouraged, frako--your understanding is in the right place, even if you misread WK's post.
We often do see creationists throwing a fog of pseudo-scientific terminology at us; I'm sure the language difference contributed to the misunderstanding, though you communicate your ideas clearly.
You'll see that WK doesn't say much, but what he does say is awfully pithy.

Have you ever been to an American wedding? Where's the vodka? Where's the marinated herring?!
-Gogol Bordello
Real things always push back.
-William James

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