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Biting Commentary about Infinity, and Beyond!

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Evolution In Action

And not just in the Pournelle/Niven sense--literally:

...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.

But a dog didn't turn into a cat, so no big deal.


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Anonymous wrote:

That is pretty neat that they saw E.Coli evolve a new metabolic pathway.

What is frustrating is that there isn't an explanation what happened. " By this time, Lenski calculated, enough bacterial cells had lived and died that all simple mutations must already have occurred several times over. "

If this wasn't a simple mutation, what happened to give it the new pathway? Did it fabircate new dna/rna out of whole cloth?

Paul F. Dietz wrote:

The blog Gene Expression, which you link to on the left, has had a couple of entries on this recently.

Paul F. Dietz wrote:

Oops, I meant The Loom, which I don't see you link to.

Rand Simberg wrote:

Actually, I do have a link to Carl Zimmer (i.e., The Loom), but I hadn't realized that he'd moved off Corante. In my next update, I was going to make him AWOL. Thanks for tracking him down for me.

Jeff Mauldin wrote:

Very interesting. I'm with anonymous--I'm wondering what happened to give it the new pathway. Was this a result of some gene or combination of genes being damaged by mutation in such a way that they no longer distinguished between citrate and whatever else they metabolize, was it expression of genetic information which had already existed and was somehow previously suppressed, or was it a new capability somehow cobbled together from other pieces or originated whole?

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This page contains a single entry by Rand Simberg published on June 19, 2008 5:47 AM.

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