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Author Topic:   Directly Observed Mutation
markoo
Inactive Member


Message 1 of 50 (153916)
10-28-2004 10:36 PM


Good evening.

I'd like to pose a question from which I do not have complete knowledge of - here it goes.

Are there observed empirical instances of mutation and NS giving rise to novel features?

Let me clarify a bit further - I'm aware of certain instances that we can infer a mutated event occurring, such as that Nylon Bug famous case. However, are there actual experiments in which a new, novel feature has been created, and researchers were able to directly pry open the gene sequence and directly notice that, in fact, there was a mutation and NS that was the direct cause of such a novel feature? IOW, are there any instances that do not have to necessarily infer that a mutated event gave rise to NS, but that we have directly observed the gene sequence itself and can conclude without a doubt it was mutation?

My abilities to scan any research are a bit limited (as is my knowledge), so any actual citations would be terrific.

Thanks for any replies.


Replies to this message:
 Message 3 by crashfrog, posted 10-29-2004 12:04 AM markoo has replied
 Message 4 by coffee_addict, posted 10-29-2004 12:11 AM markoo has not replied
 Message 5 by Coragyps, posted 10-29-2004 12:12 AM markoo has not replied
 Message 6 by Mammuthus, posted 10-29-2004 4:04 AM markoo has replied

  
AdminNosy
Administrator
Posts: 4754
From: Vancouver, BC, Canada
Joined: 11-11-2003


Message 2 of 50 (153943)
10-28-2004 11:14 PM


Thread moved here from the Proposed New Topics forum.

  
crashfrog
Member (Idle past 784 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 3 of 50 (153972)
10-29-2004 12:04 AM
Reply to: Message 1 by markoo
10-28-2004 10:36 PM


IOW, are there any instances that do not have to necessarily infer that a mutated event gave rise to NS, but that we have directly observed the gene sequence itself and can conclude without a doubt it was mutation?

Probably, but why would we have to?

The only inheritable change is that that occurs genetically, at least as far as bacteria go. (I think there's some epigenetic inheritance at work in metazoans but I'm not sure about that.)

Hypothetical situation - we observe that a bacillus population declines precipitously in response to a disadvantageous environment (or a new predator), but then rebounds. We know that a change must have happened, or else the original population would have survived. We know the change must be heritable, or else the new members of the population would have had it.

The only conclusion is that a mutation occured. There's no other kind of heritable change that can occur in a bacterium.

But, yes. It's fairly often, in bacteria at least, that we can sequence the genetics before and after the mutation, and see what locus mutated, and in what way.


This message is a reply to:
 Message 1 by markoo, posted 10-28-2004 10:36 PM markoo has replied

Replies to this message:
 Message 7 by markoo, posted 10-29-2004 11:21 AM crashfrog has replied

  
coffee_addict
Member
Posts: 3645
From: Indianapolis, IN
Joined: 03-29-2004


Message 4 of 50 (153977)
10-29-2004 12:11 AM
Reply to: Message 1 by markoo
10-28-2004 10:36 PM


Does the tetraploid rat in Argintina count?

http://www.intl-pag.org/pag/8/abstracts/pag8374.html

http://www.cricyt.edu.ar/institutos/iadiza/ojeda/grecia%202000.htm

First Tetraploid Mammal Reported

quote:
"It's a highly specialized animal that has adapted well to living with little water," Honeycutt said. "It has to have certain conditions to live. It has brushes in its mouth, for example, to strip sage for eating."


We have also observed a mutation in a lab condition where a group of snails gained a mutation that caused the shape of their shells to change preventing them from physically mate with snails of the original population.

Pinky writes:

The researchers witnessed a speciation event in a closed population they were studying, a single gene mutation changed the shell pattern of a snail, and the constraints of the new shell shape prevent the snails with the two types of shells from aligning their genitals to mate. But, the old-shelled snails could mate with the old-shelled, and the new-shelled could mate with other new-shelled snails. Thus snails with the shell-changing mutation are incapable of "interbreeding" with the ones without the mutation - even if they are sitting next to each other in the same pond - thus reproductive isolation.

http://http://www.evcforum.net/cgi-bin/dm.cgi?action=msg&f=5&t=509&m=47#47

Want more examples?

adminjar edited url to fix display width issue

This message has been edited by AdminJar, 10-30-2004 09:28 AM


He's not dead. He's electroencephalographically challenged.

The longest word in the English language is pneumonoultramicroscopicsilicovolcanoconiosis.


This message is a reply to:
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Coragyps
Member (Idle past 52 days)
Posts: 5553
From: Snyder, Texas, USA
Joined: 11-12-2002


Message 5 of 50 (153978)
10-29-2004 12:12 AM
Reply to: Message 1 by markoo
10-28-2004 10:36 PM


Here's one:
D. Ritz, et al, Science, vol 294, pp 158-160, (2001). They found a mutated bacterium that manufactured a new enzyme, and identified the exact DNA change responsible.

Register, free, at www.sciencemag.org, and you can use their search function to find and read the full paper. Some of it's pretty heavy going for us non-biologists, though.

And welcome aboard, markoo!


This message is a reply to:
 Message 1 by markoo, posted 10-28-2004 10:36 PM markoo has not replied

  
Mammuthus
Member (Idle past 5792 days)
Posts: 3085
From: Munich, Germany
Joined: 08-09-2002


Message 6 of 50 (154032)
10-29-2004 4:04 AM
Reply to: Message 1 by markoo
10-28-2004 10:36 PM


Do you mean observed in nature or do experiments in the lab count? If lab experiments count then the list of references will grow to include..well my lab notebook for one

This message is a reply to:
 Message 1 by markoo, posted 10-28-2004 10:36 PM markoo has replied

Replies to this message:
 Message 8 by markoo, posted 10-29-2004 11:22 AM Mammuthus has replied

  
markoo
Inactive Member


Message 7 of 50 (154113)
10-29-2004 11:21 AM
Reply to: Message 3 by crashfrog
10-29-2004 12:04 AM


quote:
Hypothetical situation - we observe that a bacillus population declines precipitously in response to a disadvantageous environment (or a new predator), but then rebounds. We know that a change must have happened, or else the original population would have survived. We know the change must be heritable, or else the new members of the population would have had it.

The only conclusion is that a mutation occured.


I wholeheartedly agree with your scenario, but let me give you my hypothetical situation (okay, it's not hypothetical at all really). A person I am discussing this issue with simply does not believe a mutation is the answer without verifiable, empirical evidence that the DNA (or in some cases, I suppose RNA) has been altered. I personally believe it's off the wall, but I think this person's reasoning is that if a mutation cannot actually be seen, there could be another possibility occurring - ID, or more specifically, perhaps divine intervention or something. Hence my desire to actually see (and demonstrate) DNA samples before and after a mutated event occurred, giving rise to a novel feature.

quote:
But, yes. It's fairly often, in bacteria at least, that we can sequence the genetics before and after the mutation, and see what locus mutated, and in what way.

That's what I'm after, so I'd be grateful of some more examples from you or anyone else. And to those who have posted examples already, thank you very much!


This message is a reply to:
 Message 3 by crashfrog, posted 10-29-2004 12:04 AM crashfrog has replied

Replies to this message:
 Message 9 by crashfrog, posted 10-29-2004 12:06 PM markoo has replied

  
markoo
Inactive Member


Message 8 of 50 (154114)
10-29-2004 11:22 AM
Reply to: Message 6 by Mammuthus
10-29-2004 4:04 AM


quote:
Do you mean observed in nature or do experiments in the lab count? If lab experiments count then the list of references will grow to include..well my lab notebook for one

By all means, I don't want to exclude any personal research at all! Thanks.


This message is a reply to:
 Message 6 by Mammuthus, posted 10-29-2004 4:04 AM Mammuthus has replied

Replies to this message:
 Message 10 by Mammuthus, posted 10-29-2004 12:07 PM markoo has not replied

  
crashfrog
Member (Idle past 784 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 9 of 50 (154133)
10-29-2004 12:06 PM
Reply to: Message 7 by markoo
10-29-2004 11:21 AM


A person I am discussing this issue with simply does not believe a mutation is the answer without verifiable, empirical evidence that the DNA (or in some cases, I suppose RNA) has been altered.

That's stupid. I mean, we've never directly oberved matter exchanging carrier particles for gravity, but it would be idiotic for someone to assert that, unless he saw direct observation of gravity and not just it's effects, he'd have to believe that it was invisible angels that pushed him down into his chair and not the same force that does that for the rest of us.

And anyway, even if he saw the mutation happen (assuming we had techniques that could peer inside the genetics of a cell without destroying it), whats to say that it isn't still "divine intervention"? How does he know what divine intervention looks like?


This message is a reply to:
 Message 7 by markoo, posted 10-29-2004 11:21 AM markoo has replied

Replies to this message:
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Mammuthus
Member (Idle past 5792 days)
Posts: 3085
From: Munich, Germany
Joined: 08-09-2002


Message 10 of 50 (154134)
10-29-2004 12:07 PM
Reply to: Message 8 by markoo
10-29-2004 11:22 AM


Here is a review article of dozens of experiments on this topic

Elena SF, Lenski RE. Related Articles, Links
Evolution experiments with microorganisms: the dynamics and genetic bases of adaptation.
Nat Rev Genet. 2003 Jun;4(6):457-69. Review.
Microorganisms have been mutating and evolving on Earth for billions of years. Now, a field of research has developed around the idea of using microorganisms to study evolution in action. Controlled and replicated experiments are using viruses, bacteria and yeast to investigate how their genomes and phenotypic properties evolve over hundreds and even thousands of generations. Here, we examine the dynamics of evolutionary adaptation, the genetic bases of adaptation, tradeoffs and the environmental specificity of adaptation, the origin and evolutionary consequences of mutators, and the process of drift decay in very small populations.


This message is a reply to:
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markoo
Inactive Member


Message 11 of 50 (154137)
10-29-2004 12:17 PM
Reply to: Message 9 by crashfrog
10-29-2004 12:06 PM


quote:
And anyway, even if he saw the mutation happen (assuming we had techniques that could peer inside the genetics of a cell without destroying it), whats to say that it isn't still "divine intervention"? How does he know what divine intervention looks like?

Playing devil's advocate for a second, I'll assume he'll probably discuss Dembski's EF. Putting the myriad of problems of the EF aside for the moment, I'm guessing this is what he'll likely have to fall back on, or perhaps at worst state that we can't rule out other possibilities (which really befuddle me). I really don't know why he has such incredulity on this most basic concept, nevertheless I wanted to make sure I cover all my bases.


This message is a reply to:
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Replies to this message:
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RustyShackelford 
Inactive Suspended Member


Message 12 of 50 (154350)
10-30-2004 2:27 AM
Reply to: Message 11 by markoo
10-29-2004 12:17 PM


Bacteria surviving environmental changes is evidence of natural selection, because there's clearly something hartier about the bacteria that survive than the bacteria that don't, but it'snot evidence for evolution.......anymore than faster monkies being able to get away from lions and breed fast monkey babies is. It's evidence of survival of the fittet, but not evidence that an animal can mutate to become fitter than they already are.

Most "evidence" for beneficial mutations fall into tis category.


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 Message 14 by crashfrog, posted 10-30-2004 6:16 AM RustyShackelford has replied

  
NosyNed
Member
Posts: 8971
From: Canada
Joined: 04-04-2003


Message 13 of 50 (154357)
10-30-2004 2:55 AM
Reply to: Message 12 by RustyShackelford
10-30-2004 2:27 AM


Hardier
because there's clearly something hartier about the bacteria that survive than the bacteria that don't

Yes and in many cases the difference that makes the bacteria able to survive is a specific mutation. Mutations (or some change in heritable characteristics) and selection is evolution.

Since all such changes are cummulative these heritable, selected changes can pile up and pile up.

Again, evolution is simply the selection of heritable changes and their spread through a particular gene pool. What did you think it was?

This message has been edited by NosyNed, 10-30-2004 01:55 AM


This message is a reply to:
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crashfrog
Member (Idle past 784 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 14 of 50 (154379)
10-30-2004 6:16 AM
Reply to: Message 12 by RustyShackelford
10-30-2004 2:27 AM


Bacteria surviving environmental changes is evidence of natural selection, because there's clearly something hartier about the bacteria that survive than the bacteria that don't, but it'snot evidence for evolution....

Ok, well, we have natural selection, which you admit.

We must have mutation, because that's the only heritable difference between individual bacteria. They are, after all, asexual.

So we have mutation and natural selection. We have those processes changing the frequency of alleles in the population.

So we've proved we have evolution in that population. Case closed. it really is just that simple, unless something other than science compels you to reject any conclusion that supports evolution.


This message is a reply to:
 Message 12 by RustyShackelford, posted 10-30-2004 2:27 AM RustyShackelford has replied

Replies to this message:
 Message 15 by RustyShackelford, posted 11-01-2004 1:10 AM crashfrog has replied

  
RustyShackelford 
Inactive Suspended Member


Message 15 of 50 (154739)
11-01-2004 1:10 AM
Reply to: Message 14 by crashfrog
10-30-2004 6:16 AM


But that's microevolution.......one monkey being able to run faster from a lion than others isn't a mutation which changes the organism....... how is that evidence for macroevolution?

This message is a reply to:
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Replies to this message:
 Message 16 by NosyNed, posted 11-01-2004 1:15 AM RustyShackelford has replied
 Message 17 by coffee_addict, posted 11-01-2004 1:46 AM RustyShackelford has not replied
 Message 21 by crashfrog, posted 11-01-2004 2:44 AM RustyShackelford has not replied

  
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