Friday, July 4, 2008

A Neat (Bio) Hack

Okay, this is just plain cool.

Biologist Richard Lenski has run an experiment over the last twenty years, starting with a single Escherichia coli bacterium, dividing its descendants into twelve laboratory populations, and then observing them over more than 44,000 generations.

If nothing else, the lab technique required to keep the experiment clean and reliably documented is staggering.

But somewhere around generation 31,500, one colony of bacteria suddenly acquired the ability to metabolize citrate. The mutation, expanding as it did their available food resources, dramatically increased the colony's size.

Since Lenski had saved samples of each population every 500 generations, he was able to "reboot" the experiment from earlier stages. And, as New Scientist reported, "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."

You can read the New Scientist report here. Or you can read Pharyngula's report on the drearily predictable response of the Creationists here.

But what a great hack! Simple, clean, clear, convincing. Everything that makes good science admirable.

As Always . . .

A second letter has been posted in Pastor Marcia's Journal. And Thursday's Poem du Jour takes a good long look from the bridge.


No comments: