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Author Topic:   Wright et al. on the Process of Mutation
Percy
Member
Posts: 20050
From: New Hampshire
Joined: 12-23-2000
Member Rating: 3.9


Message 29 of 296 (628027)
08-06-2011 9:00 AM
Reply to: Message 24 by John Jones
08-06-2011 7:07 AM


John Jones writes:

You might want to look at your phrase "fitness of offspring". As offspring are, by definition "fit" simply by being there, then "fitness" is not a quality "of" offspring.

As Dr Adequate implies, fitness has a well-defined meaning in biology. I can see that you're defining a "fit" offspring as one that has survived birth, but in biology fitness is measured by an organisms ability to generate offspring, or in genetic terms, to propagate its genes. Wikipedia has a good article on biological fitness. It actually calls it, and correctly in my view, "a central idea in evolutionary theory," so the odds are small that you're going to persuade evolutionary biologists to abandon the concept.

--Percy


This message is a reply to:
 Message 24 by John Jones, posted 08-06-2011 7:07 AM John Jones has responded

Replies to this message:
 Message 32 by John Jones, posted 08-06-2011 9:17 AM Percy has responded

  
Percy
Member
Posts: 20050
From: New Hampshire
Joined: 12-23-2000
Member Rating: 3.9


Message 31 of 296 (628031)
08-06-2011 9:16 AM
Reply to: Message 30 by John Jones
08-06-2011 9:07 AM


How to Quote
Hi John Jones,

Where you said this:

quote If you don't understand the concept of fitness, that is no reason why biologists should abandon it; that's a sign that you should try harder to understand it.

What is it about this concept that is giving you trouble? unquote

Instead enter this:

[qs=Dr Adequate]If you don't understand the concept of fitness, that is no reason why biologists should abandon it; that's a sign that you should try harder to understand it.

What is it about this concept that is giving you trouble?[/qs]

This will result in this appearance:

Dr Adequate writes:

If you don't understand the concept of fitness, that is no reason why biologists should abandon it; that's a sign that you should try harder to understand it.

What is it about this concept that is giving you trouble?

Also, you can click on the "Peek" button for any message to see the markup text they used to produce quotes, images, smilies, colors, fonts, etc.

--Percy


This message is a reply to:
 Message 30 by John Jones, posted 08-06-2011 9:07 AM John Jones has not yet responded

  
Percy
Member
Posts: 20050
From: New Hampshire
Joined: 12-23-2000
Member Rating: 3.9


Message 33 of 296 (628033)
08-06-2011 9:22 AM
Reply to: Message 32 by John Jones
08-06-2011 9:17 AM


Sounds like a different topic. If you want to discuss biological terminology and the errors therein you might consider proposing a new thread over at Proposed New Topics.

This message is a reply to:
 Message 32 by John Jones, posted 08-06-2011 9:17 AM John Jones has responded

Replies to this message:
 Message 39 by John Jones, posted 08-06-2011 9:50 PM Percy has responded
 Message 40 by John Jones, posted 08-06-2011 10:00 PM Percy has acknowledged this reply

  
Percy
Member
Posts: 20050
From: New Hampshire
Joined: 12-23-2000
Member Rating: 3.9


Message 34 of 296 (628034)
08-06-2011 9:29 AM
Reply to: Message 32 by John Jones
08-06-2011 9:17 AM


John Jones writes:

I wasn't able to follow your instructions for quotes. Do I have to type in a code? How do I easilyiest get or assemble the material that I want to quote?

Yes, you have to type in a code. You can experiment just by clicking on the reply button for this message. Have you done that yet? Good.

Now type this verbatim into your message text box:

[qs]This is quoted text.[/qs]

Now click on the preview button and you'll see this:

This is quoted text.

You don't want to submit this as a message, of course, so don't click on "Submit Reply." You can use your back button to get back to the thread.

All the dBCodes are documented here: dBCode Help. This same link appears to the left of the message box where you enter text. You can also use HTML in messages. And smilies, too, click on the Smilies Table link that also appears to the left of the message box.

--Percy


This message is a reply to:
 Message 32 by John Jones, posted 08-06-2011 9:17 AM John Jones has not yet responded

  
Percy
Member
Posts: 20050
From: New Hampshire
Joined: 12-23-2000
Member Rating: 3.9


Message 44 of 296 (628163)
08-07-2011 6:35 AM
Reply to: Message 39 by John Jones
08-06-2011 9:50 PM


John Jones writes:

It isn't a different topic to enquire about the significance of a term that is employed in that topic. It would, rather, seem to be key to it.

Inquiring about the definition of a term is fine, encouraged in fact, but disputing the definition of a term fundamental to evolution probably deserves its own topic. Back in Message 29 I said that in biology fitness is measured by an organisms ability to generate offspring, or in genetic terms, to propagate its genes. I also pointed you at Wikipedia's article on biological fitness. If you have more questions about the definition of fitness I'm sure everyone would be glad to answer them.

But if you don't like the definition and have problems with the concept itself, this probably isn't the right thread for discussing it.

--Percy


This message is a reply to:
 Message 39 by John Jones, posted 08-06-2011 9:50 PM John Jones has not yet responded

  
Percy
Member
Posts: 20050
From: New Hampshire
Joined: 12-23-2000
Member Rating: 3.9


Message 48 of 296 (628480)
08-09-2011 9:35 PM
Reply to: Message 46 by John Jones
08-09-2011 6:53 PM


John Jones writes:

[qsPerhaps you could explain how it is lacking? Are you saying that fitness is not a factor in the propagation of a genome?qs]

You continue to have trouble with quoting. I think we should assume you've never used a discussion board before. Let us know if there is some way we can help you figure this out.

(also note, if you argue that success of reproduction of the offspring makes them fit...

No one is arguing that "success of reproduction of the offspring makes them fit." Reproductive success is an indicator of fitness, not a cause. Fitness is a result of adaptation, which itself is a result of generations of descent with modification and natural selection, also known as evolution.

--Percy


This message is a reply to:
 Message 46 by John Jones, posted 08-09-2011 6:53 PM John Jones has not yet responded

  
Percy
Member
Posts: 20050
From: New Hampshire
Joined: 12-23-2000
Member Rating: 3.9


Message 53 of 296 (631600)
09-01-2011 9:47 PM
Reply to: Message 51 by Taq
09-01-2011 7:18 PM


Hi Taq,

Not sure why you're jumping all over Shadow on this one:

shadow writes:

If specific alles increase the chances of an organism producing more offspring than others in a given enviroment, and these alles production are more than those w/o the mutation, this sound alot like mutations for fitness, that are not "random" as per Darwin.

Because he says "producing more offspring," his later use of the word production also refers to offspring. He's trying to describe the cause of differential reproduction as being allele mutations that allow organisms to produce more offspring than others of their species without the mutation.

He only goes off the rails at the end where he calls mutations that produce greater fitness as being non-random, and also in ascribing this erroneous view to Darwin, who though he preceded the discovery of mutations definitely viewed variation as random.

--Percy


This message is a reply to:
 Message 51 by Taq, posted 09-01-2011 7:18 PM Taq has not yet responded

Replies to this message:
 Message 54 by Wounded King, posted 09-02-2011 4:43 AM Percy has responded

  
Percy
Member
Posts: 20050
From: New Hampshire
Joined: 12-23-2000
Member Rating: 3.9


Message 55 of 296 (631640)
09-02-2011 7:10 AM
Reply to: Message 54 by Wounded King
09-02-2011 4:43 AM


Re: I'm not so sure
Hi WK - I think you're right, sorry Taq.

Gee, and I thought Shadow was taking a step toward understanding what really happens. Too bad.

--Percy


This message is a reply to:
 Message 54 by Wounded King, posted 09-02-2011 4:43 AM Wounded King has not yet responded

  
Percy
Member
Posts: 20050
From: New Hampshire
Joined: 12-23-2000
Member Rating: 3.9


Message 93 of 296 (634548)
09-22-2011 2:08 PM
Reply to: Message 92 by shadow71
09-22-2011 1:52 PM


Re: beneficial mutations
shadow71 writes:

Lets discuss Darwin's theory, and the modern synthesis up to the late 60's, when molecular genetics became more prevelant.

Given this and your other recent posts, I'm not sure that what you want to discuss belongs in this thread. This is from the opening post:

Taq writes:

In this thread I would like to explore a specific paper written by Wright et al.

...

With respect to the paper, I will attempt to demonstrate that the same mechanisms that produce reversions in leuB- organisms will also cause deleterious mutations in very important and vital genes as well as mutations which do not change the fitness of offspring.

Do your recent posts relate to the topic? If so, can you make clear how they relate to the topic for the benefit of those of us trying to follow along?

--Percy


This message is a reply to:
 Message 92 by shadow71, posted 09-22-2011 1:52 PM shadow71 has responded

Replies to this message:
 Message 94 by shadow71, posted 09-22-2011 4:19 PM Percy has responded

  
Percy
Member
Posts: 20050
From: New Hampshire
Joined: 12-23-2000
Member Rating: 3.9


(1)
Message 95 of 296 (634562)
09-22-2011 5:17 PM
Reply to: Message 94 by shadow71
09-22-2011 4:19 PM


Re: Do you agree that this specificity is not compatable with NeoRe: beneficial mutations
shadow71 writes:

Just trying to establish if Wright's paper does in fact comply with the Darwinian theory up to the modern synthesis, or if in fact Wright is of the opinion that her findings in the paper are not compatable with Darwinian theory up to the modern synthesis.

This is not related to the topic, but yes, Wright's paper is completely compatible with the modern synthesis. The modern synthesis between the sciences of evolution and genetics developed in the 1930's out of studies that proved they were not only compatible but reinforced each other.

But the modern synthesis is not a combination of the state of evolution and genetics in the 1930's, nor their state in the 1960's, nor in any other time period. Science is not static. Everything we've learned about evolution and genetics since the 1930's only reinforces our confidence that these two sciences are mutually interdependent. Both are necessary to a proper understanding of the history of life on earth and of modern biology.

But that's all beside the point. In this thread Taq is using the Wright paper to show that the mechanisms that drive faster adaptation also produce neutral and deleterious mutations, demonstrating that specific beneficial mutations are not produced.

--Percy


This message is a reply to:
 Message 94 by shadow71, posted 09-22-2011 4:19 PM shadow71 has not yet responded

  
Percy
Member
Posts: 20050
From: New Hampshire
Joined: 12-23-2000
Member Rating: 3.9


Message 98 of 296 (634718)
09-23-2011 2:19 PM
Reply to: Message 96 by Taq
09-23-2011 12:05 PM


Re: Do you agree that this specificity is not compatable with NeoRe: beneficial mutations
Taq writes:

The problem here is that Wright et al. cite work done by Weismann in 1893, well before the Modern Synthesis was complete. The author's opinion of what the Modern Synthesis is or isn't seems to differ from the general opinion of most scientists.

You're referring to Wright's concluding paragraph:

Wright et al writes:

The current paradigm of neo-Darwinism as formulated by Weisman (59) rejects any influence of the environment on the direction of variation. However, prolonged nutritional stress results in a general increase in mutation rates; the introduction of environmental effects on specific mutation rates is a reasonable extension of what is known, especially because mechanisms by which starvation can immediately and specifically affect rates of transcription and mutation are consistent with accepted principles of molecular biology. The proposed mechanism of derepression-induced hypermutation provides the critical link between mutations and the metabolic activities evoked by specific conditions of environmental stress, increasing the availability of variants most likely to evolve in that environment.

She begins this paragraph, with, "The current paradigm of neo-Darwinism as formulated by Weisman (59)..." I would never have followed the reference to discover that it's from 1893, so thanks for the information. Does Wright really believe that the "current paradigm of neo-Darwinism" had not changed in the intervening 106 years before she wrote her paper? How, uh, interesting.

She nonetheless continues to describe her findings as "a reasonable extension," thus confirming that she doesn't view her findings as indicating environmentally influenced direction. The Wikipedia article on Neo-Darwinism says that Weisman rejected any form of Lamarckism because "he could see no obvious means of communication between" environment and "germ plasm." But now we know that such communication channels do exist.

I honestly don't understand the fuss from IDists about environment influencing the direction of evolution. It's an ability that could evolve, and someday we may discover it already has, and that would still say nothing pro or con about a designer.

--Percy


This message is a reply to:
 Message 96 by Taq, posted 09-23-2011 12:05 PM Taq has responded

Replies to this message:
 Message 100 by Taq, posted 09-23-2011 4:36 PM Percy has acknowledged this reply
 Message 121 by zi ko, posted 09-27-2011 5:57 AM Percy has acknowledged this reply

  
Percy
Member
Posts: 20050
From: New Hampshire
Joined: 12-23-2000
Member Rating: 3.9


Message 103 of 296 (634764)
09-23-2011 8:47 PM
Reply to: Message 99 by shadow71
09-23-2011 4:26 PM


Back to the Topic
Despite receiving the same answer, you continue repeating the same off-topic question. It is a good question and well deserving of spending a few posts on, but the question has been answered several times and as it is not the topic I think most would welcome it if you could move on to issues related to the topic.

--Percy


This message is a reply to:
 Message 99 by shadow71, posted 09-23-2011 4:26 PM shadow71 has not yet responded

  
Percy
Member
Posts: 20050
From: New Hampshire
Joined: 12-23-2000
Member Rating: 3.9


(1)
Message 105 of 296 (634922)
09-24-2011 8:43 PM
Reply to: Message 104 by shadow71
09-24-2011 8:34 PM


Re: Do you agree that this specificity is not compatable with NeoRe: beneficial mutations
shadow71 writes:

Thank you for you patience and understanding. I know it must be hard to know it all and deal with these other idiots, especially when they challenge your absoutely unassailable beliefs.

Are you daft? Do you somehow think parroting the exact same question in the face of repeated answers is some kind of profound search for knowledge deserving of respect? Maybe you could return to your other thread where you were already ignoring answers about Shapiro and the modern synthesis.

Back to the topic. This thread is about the Wright paper's demonstration that environmental factors do not direct evolution in specific directions.

--Percy


This message is a reply to:
 Message 104 by shadow71, posted 09-24-2011 8:34 PM shadow71 has responded

Replies to this message:
 Message 106 by shadow71, posted 09-25-2011 3:04 PM Percy has responded

  
Percy
Member
Posts: 20050
From: New Hampshire
Joined: 12-23-2000
Member Rating: 3.9


Message 107 of 296 (635022)
09-25-2011 7:59 PM
Reply to: Message 106 by shadow71
09-25-2011 3:04 PM


Re: Do you agree that this specificity is not compatable with NeoRe: beneficial mutations
shadow71 writes:

If you read the Wright quote above she seems to be saying that in fact the enviomental factors are directing evolution in specific directions.

I emphasize the later part of her quote:

Wright writes:

However, prolonged nutritional stress results in a general increase in mutation rates; the introduction of environmental effects on specific mutation rates is a reasonable extension of what is known, especially because mechanisms by which starvation can immediately and specifically affect rates of transcription and mutation are consistent with accepted principles of molecular biology. The proposed mechanism of derepression-induced hypermutation provides the critical link between mutations and the metabolic activities evoked by specific conditions of environmental stress, increasing the availability of variants most likely to evolve in that environment.

Am I interpreting this incorrectly?

Yes, of course you're interpreting this incorrectly. The last sentence, which is what I think you're focusing on, is talking about variants produced by increasing the random mutation rate in a specific region of DNA. The mutations are random with respect to adaptation, but they're occurring in a region with a greater likelihood of having an impact on adaptation in that environment. It represents an improvement over increasing the mutation rate generally throughout the DNA.

--Percy


This message is a reply to:
 Message 106 by shadow71, posted 09-25-2011 3:04 PM shadow71 has not yet responded

  
Percy
Member
Posts: 20050
From: New Hampshire
Joined: 12-23-2000
Member Rating: 3.9


Message 111 of 296 (635102)
09-26-2011 5:16 PM
Reply to: Message 110 by shadow71
09-26-2011 5:03 PM


Re: Do you agree that this specificity is not compatable with NeoRe: beneficial mutations
Hi Shadow,

You're again asking the same question repeatedly. Let me ask you a question. What do you think Taq was getting at when he asked this of you:

Taz writes:

Also, please explain why the leuB- reversion rate is only 1 in every 500 million divisions.

Hint: It bears directly on the passage from Wright you just quoted.

It is rare in a technical paper for a single sentence to contain all the qualifications and constraints described and explained throughout the paper. There are always going to be sentences in any paper that seem to provide enough wiggle room for you to keep alive the hope that the paper is saying what you wish in your heart it was saying. Cherry picking these sentences isn't going to get you anywhere with people who have read and understood the entire paper. Or as someone says in their signature, we could agree with you, but then we'd all be wrong.

--Percy


This message is a reply to:
 Message 110 by shadow71, posted 09-26-2011 5:03 PM shadow71 has not yet responded

  
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