|
Register | Sign In |
|
QuickSearch
Thread ▼ Details |
|
Thread Info
|
|
|
Author | Topic: Directly Observed Mutation | |||||||||||||||||||||||||||
markoo Inactive Member |
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.
|
|||||||||||||||||||||||||||
AdminNosy Administrator Posts: 4755 From: Vancouver, BC, Canada Joined: |
Thread moved here from the Proposed New Topics forum.
|
|||||||||||||||||||||||||||
crashfrog Member (Idle past 1715 days) Posts: 19762 From: Silver Spring, MD Joined: |
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.
|
|||||||||||||||||||||||||||
coffee_addict Member (Idle past 116 days) Posts: 3645 From: Indianapolis, IN Joined: |
Does the tetraploid rat in Argintina count?
Page not found - My Kratom And Weed Blog http://www.cricyt.edu.ar/...s/iadiza/ojeda/grecia%202000.htm
First Tetraploid Mammal Reported quote: 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://EvC Forum: Natural Selection - not natural? 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.
|
|||||||||||||||||||||||||||
Coragyps Member (Idle past 983 days) Posts: 5553 From: Snyder, Texas, USA Joined: |
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 Science | AAAS, 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!
|
|||||||||||||||||||||||||||
Mammuthus Member (Idle past 6724 days) Posts: 3085 From: Munich, Germany Joined: |
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
|
|||||||||||||||||||||||||||
markoo Inactive Member |
quote: 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: 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!
|
|||||||||||||||||||||||||||
markoo Inactive Member |
quote: By all means, I don't want to exclude any personal research at all! Thanks.
|
|||||||||||||||||||||||||||
crashfrog Member (Idle past 1715 days) Posts: 19762 From: Silver Spring, MD Joined: |
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?
|
|||||||||||||||||||||||||||
Mammuthus Member (Idle past 6724 days) Posts: 3085 From: Munich, Germany Joined: |
Here is a review article of dozens of experiments on this topic
Elena SF, Lenski RE. Related Articles, LinksEvolution 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.
|
|||||||||||||||||||||||||||
markoo Inactive Member |
quote: 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.
|
|||||||||||||||||||||||||||
RustyShackelford  Inactive Member |
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.
|
|||||||||||||||||||||||||||
NosyNed Member Posts: 9011 From: Canada Joined: |
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
|
|||||||||||||||||||||||||||
crashfrog Member (Idle past 1715 days) Posts: 19762 From: Silver Spring, MD Joined: |
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.
|
|||||||||||||||||||||||||||
RustyShackelford  Inactive Member |
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?
|
|
|
Do Nothing Button
Copyright 2001-2023 by EvC Forum, All Rights Reserved
Version 4.2
Innovative software from Qwixotic © 2024