Topic: Bacteria make major evolutionary shift in the lab

[Nemesis]

Link to full article

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.

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.

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.

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'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."

It will be interesting to see what the mutations were that ended with this effect. 

[Centurus]

I wonder if within another 30 or 40 thousand generations, they'll be able to play basic poker.

But seriously, this is one huge step in understanding the evolutionary process.  And who knows, it could even provide insight into making some treatments or vaccines for certain illnesses and diseases.

Just a thought.

[Dracho]

Get one to develop into a multi-celled orgnanism and you'll have something.

[Ravok]

Get one to develop into a multi-celled orgnanism and you'll have something.

 Well If the time line is roughly the same,check back again, in about 500,000,000 years or so.

[Centurus]

Get one to develop into a multi-celled orgnanism and you'll have something.

 Well If the time line is roughly the same,check back again, in about 500,000,000 years or so.

Unfortunately, I'll still be around by then, and I still wouldn't have gotten any.  Oh well.

[Dracho]

Three words:

Nevada Road Trip

[Bonk]

In time, when I finally have the budget () with ultra-high-resolution-spectroscopic-magnetic-resonance-imaging I could show you movies of it at the molecular scale in real time. We have the processing power available now, we did not when I conceived of the idea fourteen years ago. Storage capacities are getting there too. Evolutionary biology always comes down to chemistry for me, because it is.

To truly understand this, we need to SEE it. What proteins? What RNA/DNA? Mechanisms of the actual mutations? I have no doubts about evolution, I live it. I'd like to visualise molecular biology with modern instrumentation of my own design. THen we could build a base of knowledge for a better understanding of the molecular mechanisms of evolution.

[marstone]

Bonk, the university I work at is suppose to be selling an electron microscope in the surplus sale today, would you need one?

[knightstorm]

Link to full article

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.

 

I would never have the patience to do something like that.

[Bonk]

Bonk, the university I work at is suppose to be selling an electron microscope in the surplus sale today, would you need one?

Interesting, but no. I just need about 2.5Mil to get started, lol! Actually, 250K would get me started...

[Centurus]

Three words:

Nevada Road Trip

Does that mean you'll give me a non-recourse loan for about 10 grand?   

[GE-Raven]

Get one to develop into a multi-celled orgnanism and you'll have something.

 Well If the time line is roughly the same,check back again, in about 500,000,000 years or so.

That has always been my beef with macro evolution... lets say that the average "major" mutation (that would move it after a while to a new species) was 1/4 as many generations...  In animals that have 20 year generations (or even 10) how do you get major changes?  The earth just isn't old enough to get all the changes in needed, especially when you work in all the Near extinction events that often reset the clock.

GE-Raven

[Ravok]

Get one to develop into a multi-celled orgnanism and you'll have something.

 Well If the time line is roughly the same,check back again, in about 500,000,000 years or so.

That has always been my beef with macro evolution... lets say that the average "major" mutation (that would move it after a while to a new species) was 1/4 as many generations...  In animals that have 20 year generations (or even 10) how do you get major changes?  The earth just isn't old enough to get all the changes in needed, especially when you work in all the Near extinction events that often reset the clock.

GE-Raven

 I have wondered the same myself.

[Dracho]

If you notice, evolution seems to explode after mass extinction events.  I personally think open niches in the food chain is what turns evolution's accelerated mode on and off.

[Dash Jones]

If you notice, evolution seems to explode after mass extinction events. I personally think open niches in the food chain is what turns evolution's accelerated mode on and off.

From the bottleneck evolutionary type.  Seriously, it's called the bottleneck, it's when a mutation comes from a small group, or there's a huge death amongst the group and the smaller group that survives has some mutative quality that allows it to survive when all the others die off.

[Panzergranate]

E. Coli.... isn't that the bacteria that normally resides in everyones butts, causes fart gas, and also causes food poisoning outbreaks when some git can't be arsed to wash their hands after using the toilets.

So.... this means that someone's butt is hosting what could be the progenators of an advanced civillisation that will rule the universe in a few million year's time.

[marstone]

E. Coli.... isn't that the bacteria that normally resides in everyones butts, causes fart gas, and also causes food poisoning outbreaks when some git can't be arsed to wash their hands after using the toilets.

So.... this means that someone's butt is hosting what could be the progenators of an advanced civillisation that will rule the universe in a few million year's time.

Actually E.Coli isn't the one that lives in your butt.  But is mostly everywhere but not in much quantity, 'til it finds some good food.

[Nemesis]

I'm no evolutionary scientist but as I understand it evolution tends to occur fastest in populations that are under stress.  In other words in an environment with a relatively high mortality rate or low rate of reproduction. 

These bacteria are kept in an idealized environment, nothing to stress them and drive evolution. 

It would be interesting if someone were to reproduce the experiment but with double the number of samples and then have 1/2 of the samples meet temperature changes, varying food types and quantities over time and perhaps a predatory species.  Would it evolve more as evolutionary theories would seem to predict than the "control" colonies or not?

[Panzergranate]

So with the stress caused by the cost of oil and gas.... is the human race about to evolve....

[Centurus]

So with the stress caused by the cost of oil and gas.... is the human race about to evolve....

Look at George W.  That should be a prime example that in some cases, the human race is de-evolving.