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 HagbardCeline
ProfessionalAsshole
Registered: 05/10/03
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 Major evolutionary change has finally been observed
#8507185 - 06/10/08 12:17 PM (3 months, 30 days ago) |
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Quite fitting with all the recent talk in here of evolution.
http://www.newscientist.com/article/dn14094-bacteria-make-major-evolutionary-shift-in-the-lab.html?DCMP=ILC-hmts&nsref=specrt10_pic
Bacteria make major evolutionary shift in the lab
* 22:00 09 June 2008
* NewScientist.com news service
* Bob Holmes
A major evolutionary innovation has unfurled right in front of researchers' eyes. It's the first time evolution has been caught in the act of making such a rare and complex new trait.
And because the species in question is a bacterium, scientists have been able to replay history to show how this evolutionary novelty grew from the accumulation of unpredictable, chance events.
Twenty years ago, evolutionary biologist Richard Lenski of Michigan State University in East Lansing, US, took a single Escherichia coli bacterium and used its descendants to found 12 laboratory populations.
The 12 have been growing ever since, gradually accumulating mutations and evolving for more than 44,000 generations, while Lenski watches what happens.
Profound change
Mostly, the patterns Lenski saw were similar in each separate population. All 12 evolved larger cells, for example, as well as faster growth rates on the glucose they were fed, and lower peak population densities.
But sometime around the 31,500th generation, something dramatic happened in just one of the populations – the bacteria suddenly acquired the ability to metabolise citrate, a second nutrient in their culture medium that E. coli normally cannot use.
Indeed, the inability to use citrate is one of the traits by which bacteriologists distinguish E. coli from other species. The citrate-using mutants increased in population size and diversity.
"It's the most profound change we have seen during the experiment. This was clearly something quite different for them, and it's outside what was normally considered the bounds of E. coli as a species, which makes it especially interesting," says Lenski.
Rare mutation?
By this time, Lenski calculated, enough bacterial cells had lived and died that all simple mutations must already have occurred several times over.
That meant the "citrate-plus" trait must have been something special – either it was a single mutation of an unusually improbable sort, a rare chromosome inversion, say, or else gaining the ability to use citrate required the accumulation of several mutations in sequence.
To find out which, Lenski turned to his freezer, where he had saved samples of each population every 500 generations. These allowed him to replay history from any starting point he chose, by reviving the bacteria and letting evolution "replay" again.
Would the same population evolve Cit+ again, he wondered, or would any of the 12 be equally likely to hit the jackpot?
Evidence of evolution
The replays showed that even when he looked at trillions of cells, only the original population re-evolved Cit+ – and only when he started the replay from generation 20,000 or greater. Something, he concluded, must have happened around generation 20,000 that laid the groundwork for Cit+ to later evolve.
Lenski and his colleagues are now working to identify just what that earlier change was, and how it made the Cit+ mutation possible more than 10,000 generations later.
In the meantime, the experiment stands as proof that evolution does not always lead to the best possible outcome. Instead, a chance event can sometimes open evolutionary doors for one population that remain forever closed to other populations with different histories.
Lenski's experiment is also yet another poke in the eye for anti-evolutionists, notes Jerry Coyne, an evolutionary biologist at the University of Chicago. "The thing I like most is it says you can get these complex traits evolving by a combination of unlikely events," he says. "That's just what creationists say can't happen."
Journal reference: Proceedings of the National Academy of Sciences (DOI: 10.1073/pnas.0803151105)
Read our Evolution: 24 myths and misconceptions special report.
Evolution - Learn more about the struggle to survive in our comprehensive special report.
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Katie Couric, while interviewing a Marine sniper, asked :
'What do you feel when you shoot a Terrorist?'
The Marine shrugged and replied,
'A slight recoil
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 Seuss
Error: divide byzero
Registered: 04/27/01
Posts: 16,310
Loc: Caribbean
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Re: Major evolutionary change has finally been observed [Re: HagbardCeline]
#8507458 - 06/10/08 01:45 PM (3 months, 30 days ago) |
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Very cool! (And about time.)
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Just another spore in the wind.
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Annom
※※※※※※
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Re: Major evolutionary change has finally been observed [Re: HagbardCeline]
#8508162 - 06/10/08 05:33 PM (3 months, 30 days ago) |
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Very cool experiment with a great result 
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RuNE
bomberman
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Loc: tartarus
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Re: Major evolutionary change has finally been observed [Re: HagbardCeline]
#8509107 - 06/10/08 09:34 PM (3 months, 30 days ago) |
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Take that, creationists! 
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~Happy sailing~
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rev 766
gum flappin' scallywag
Registered: 04/08/08
Posts: 732
Last seen: 2 hours, 3 minutes
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Re: Major evolutionary change has finally been observed [Re: RuNE]
#8509332 - 06/10/08 10:32 PM (3 months, 30 days ago) |
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sweet. just needed this to be in my posts. may make a comment tomorrow.
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praise "bob"
did you mean shmooed-R.I.P.
"drought besets the mind, decay besets the man"-me
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 tripsis
biophile-misanthropist-doofer
Registered: 04/13/08
Posts: 3,888
Loc: Gondwana
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Re: Major evolutionary change has finally been observed [Re: rev 766]
#8509453 - 06/10/08 11:11 PM (3 months, 30 days ago) |
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Great. Good to see more evidence. The evolution of a new species has been recorded before but this article is yet another piece of irrefutable evidence of evolution.
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Since we depend on an abundance of functioning ecosystems to cleanse our water, enrich our soil and manufacture the very air we breathe, biodiversity is clearly not an inheritance to be discarded carelessly - Edward O. Wilson 1992
Edited by tripsis (06/10/08 11:18 PM)
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Ballarat_Bandit
Techno-Drugs
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Re: Major evolutionary change has finally been observed [Re: tripsis]
#8509519 - 06/10/08 11:34 PM (3 months, 30 days ago) |
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God damn impressive, excuse the pun.
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Seuss
Error: divide byzero
Registered: 04/27/01
Posts: 16,310
Loc: Caribbean
Last seen: 2 minutes, 32 seconds
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Re: Major evolutionary change has finally been observed [Re: tripsis]
#8510084 - 06/11/08 05:02 AM (3 months, 30 days ago) |
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> The evolution of a new species has been recorded before
Depending upon the selected definitions of species and evolution. *grin* (I know, stubborn to the core... )
However, even I would have to concede this round, assuming that the research is valid (which I suspect it is).
I only need once more bit to make me really happy, and that would be somebody creating life from inert components. (In other words, making life without using anything that was made by life. Injecting DNA into an existing cell body, or using existing cells as engines to create custom DNA don't count. I'm talking about life from raw elemental components. Something that has yet to be accomplished.)
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Just another spore in the wind.
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Anno
Experimenter
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Re: Major evolutionary change has finally been observed [Re: Seuss]
#8510180 - 06/11/08 06:24 AM (3 months, 30 days ago) |
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Give me the raw elemental components and 700,000,000 years, and I will give it to you.
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The Rich Jerk
Grow Mushrooms from Spores - PF-Tek for Simple Minds
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HagbardCeline
ProfessionalAsshole
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Loc: In a deep, deep, deep, da...
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Re: Major evolutionary change has finally been observed [Re: tripsis]
#8510237 - 06/11/08 06:54 AM (3 months, 30 days ago) |
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Quote:
tripsis said:
The evolution of a new species has been recorded before
Like Seuss, I have some trouble with these claims. In some of them, it seems that any variation from the supposed original is claimed as new species when much of it is likely attributable to reccessive genes. By their definitions we should have thousands of species of dogs.
Regardless, the instances you're probably citing aren't as exciting as this though because they didn't develop any novel abilities.
--------------------
Katie Couric, while interviewing a Marine sniper, asked :
'What do you feel when you shoot a Terrorist?'
The Marine shrugged and replied,
'A slight recoil
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old mushmellow
mushmaker
Registered: 03/15/08
Posts: 260
Loc: the dome
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Re: Major evolutionary change has finally been observed [Re: HagbardCeline]
#8510275 - 06/11/08 07:09 AM (3 months, 30 days ago) |
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Love the sign, hag!
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It is tempting to say that one gets from the LSD encounter what one deserves, "Quidquid recipietur secundum modum recipient is recipietur" our nature determines what we receive.
Dr. sidney Cohen
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tripsis
biophile-misanthropist-doofer
Registered: 04/13/08
Posts: 3,888
Loc: Gondwana
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Re: Major evolutionary change has finally been observed [Re: Seuss]
#8510358 - 06/11/08 07:43 AM (3 months, 30 days ago) |
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Quote:
HagbardCeline said:
Quote:
tripsis said:
The evolution of a new species has been recorded before
Like Seuss, I have some trouble with these claims. In some of them, it seems that any variation from the supposed original is claimed as new species when much of it is likely attributable to reccessive genes. By their definitions we should have thousands of species of dogs.
Regardless, the instances you're probably citing aren't as exciting as this though because they didn't develop any novel abilities.
Firstly, by who's definitions?
If you want a proper definition to go by try this: "Species are groups of actually or potentially interbreeding natural populations which are reproductively isolated from all other such groups". Taking this defintion it is clear that your statement "that we should have thousands of species of dogs" is wrong. Dogs can all interbreed, there is not a single breed yet that can't give rise to fertile young with another. For a new species to arise it genetics have to become sufficiently different so that it can not interbreed with similar populations.
Quote:
Seuss said:
> The evolution of a new species has been recorded before
Depending upon the selected definitions of species and evolution. *grin* (I know, stubborn to the core... )
However, even I would have to concede this round, assuming that the research is valid (which I suspect it is).
Okay, the time has come. Evidence:
This is a case of sympatric speciation, and evidence of the present day rise of a new species.
In the USA there is a fly called Rhagoletis pomonella. This fly naturally attacks Hawthorn bushes, being attracted to the developing fruits, where they mate and the females oviposit. In the mid-1800's in Hudson Valley, some individuals switched to introduced apples, which flower at a different time from Hawthorns. Over time the two 'species' have become genetically distinct.
Quote:
Seuss said:
I only need once more bit to make me really happy, and that would be somebody creating life from inert components. (In other words, making life without using anything that was made by life. Injecting DNA into an existing cell body, or using existing cells as engines to create custom DNA don't count. I'm talking about life from raw elemental components. Something that has yet to be accomplished.)
This depends on your definition of life. You may be interested in the creation of proteinoids. These are made by heating together mixtures of dry amino acids to 150C-180C, usually in molten aspartic acid. When cooled and mixed with water the mixtures from protein-like molecules via condensation reactions. These molecules spontaneously form cell-like structures that grow and divide, carrying out basic metabolic activites and creating selective pressure for the molecules most effective at this. Proteinoids are not living, but they certainly give an idea of how life may have started.
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Since we depend on an abundance of functioning ecosystems to cleanse our water, enrich our soil and manufacture the very air we breathe, biodiversity is clearly not an inheritance to be discarded carelessly - Edward O. Wilson 1992
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BrainChemistry
Duplicarius
Registered: 06/19/07
Posts: 1,088
Loc: Mountains of N. America
Last seen: 7 hours, 55 minutes
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Re: Major evolutionary change has finally been observed [Re: HagbardCeline]
#8510419 - 06/11/08 08:06 AM (3 months, 30 days ago) |
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How long until all our Lysol sprays develop a bacteria big enough to munch our faces off???
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Images of broken light which
dance before me like a million eyes
That call me on and on across the universe
Thoughts meander like a
restless wind inside a letter box
they tumble blindly as
they make their way across the universe
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johnm214
Registered: 05/31/07
Posts: 6,469
Loc: Americas
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Re: Major evolutionary change has finally been observed [Re: RuNE]
#8512464 - 06/11/08 06:39 PM (3 months, 29 days ago) |
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Quote:
RuNE said:
Take that, creationists!
Has nothing to do w/ creationism, except those that claim things can't evolve- biblical nuts
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johnm214
Registered: 05/31/07
Posts: 6,469
Loc: Americas
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Re: Major evolutionary change has finally been observed [Re: johnm214]
#8512535 - 06/11/08 06:59 PM (3 months, 29 days ago) |
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Thanks tripsis, that stuff is interesting about the proteinoids, I'll check it out, haven't heard of them.
Regarding this whole claim, what is the big deal? I don't understand...
First, it seems e coli can metabolize citrate normally, just in anoxic conditions. Am I wrong here or is the article wrong? Are they really reporting that the strain can now aerobically metabolise citrate, or just that they can ferment in oxic conditions? What is the deal?
Quote:
the bacteria suddenly acquired the ability to metabolise citrate, a second nutrient in their culture medium that E. coli normally cannot use.
Second, what actually changed in the metabolic machinery? What prevented oxic metabolism of citrate in the first place, and what now allows it? Is it just some regulation of the enzymes that was removed or what?
If its a minor change in the same enzymes allready present, this would seem to be pretty similar to the common Ames tests where backmutations are measured and detected.
The article doesn't really explain what happened... ANyone know? Later I'll see if I can get more information or find the article.
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johnm214
Registered: 05/31/07
Posts: 6,469
Loc: Americas
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Re: Major evolutionary change has finally been observed [Re: johnm214]
#8512857 - 06/11/08 08:32 PM (3 months, 29 days ago) |
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hmm
Looking at proteinoids they just seem like soap bubbles to me w/ amino acids instead
Is there something more? They don't really seem to have a metabolism, genome, or any way to reproduce besides fission- which since they don't have metabolisms, really, they don't really grow afterwords except through passive means.
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tripsis
biophile-misanthropist-doofer
Registered: 04/13/08
Posts: 3,888
Loc: Gondwana
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Re: Major evolutionary change has finally been observed [Re: johnm214]
#8512900 - 06/11/08 08:42 PM (3 months, 29 days ago) |
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No, they have no genome, they are not alive. They only carry out basic "metabolism" through chemical reactions of taking in the chemicals they need which allows them to grow and divide. You are correct, they only reproduce by fission, but so do bacteria. There is nothing advanced about them, but it is an interesting and potential way that life could have begun.
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Since we depend on an abundance of functioning ecosystems to cleanse our water, enrich our soil and manufacture the very air we breathe, biodiversity is clearly not an inheritance to be discarded carelessly - Edward O. Wilson 1992
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Dizzwizzle
Philanthropist
Registered: 05/20/07
Posts: 2,180
Loc: Falling From Grace....
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Re: Major evolutionary change has finally been observed [Re: tripsis]
#8519099 - 06/13/08 10:33 AM (3 months, 28 days ago) |
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haha take that anti-evolutionists 
Thats cool...
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The Sweet smell of Sophistication 
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johnm214
Registered: 05/31/07
Posts: 6,469
Loc: Americas
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Re: Major evolutionary change has finally been observed [Re: Dizzwizzle]
#8520247 - 06/13/08 03:29 PM (3 months, 27 days ago) |
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Quote:
Regarding this whole claim, what is the big deal? I don't understand...
Guess that killed the thread....
Anyways, I can't find the article. Looks like there's about a two issue embargo on it.
If anyone of the enthusiastic folks here can explain what happened, see my previous questions, I'd be interested.
Can't find much decent coverage via articles... maybe some nerdy blogger knows something
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tripsis
biophile-misanthropist-doofer
Registered: 04/13/08
Posts: 3,888
Loc: Gondwana
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Re: Major evolutionary change has finally been observed [Re: johnm214]
#8520847 - 06/13/08 05:38 PM (3 months, 27 days ago) |
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Hahaha, you'll never get an answer now. No one will want to own up to being a nerdy blogger.
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Since we depend on an abundance of functioning ecosystems to cleanse our water, enrich our soil and manufacture the very air we breathe, biodiversity is clearly not an inheritance to be discarded carelessly - Edward O. Wilson 1992
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