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EVOLUTION AT WORK

Filed at 8:05 am under by dcobranchi

Via RedStateRabble comes this summary of some very cool recent research at Rice University.

Rice University biologists, using an ingenious experiment that forced bacteria to compete in a head-to-head contest for evolutionary dominance, today offer the first glimpse of how individual genetic-level adaptations play out as Darwinian natural selection in large populations. The results appear in the May 19 issue of Molecular Cell.

…Rice’s study involved the heat-loving bacteria G. stearothermophilus, which thrives at up to 73 degrees Celsius (163 F). Shamoo and graduate students Rafael Couñago and undergraduate Stephen Chen used a mutant strain of the microbe that was unable to make a key protein that the bacteria needed to regulate its metabolism at high temperatures. They grew the bacteria for one month in fermentor, raising the temperature a half degree Celsius each day.

Over a span of 1,500 generations, the percentage of mutant strains inside the fermentor ebbed and flowed as the single-celled microbes competed for dominance. Eventually, one strain squeezed out almost all the competition by virtue of its ability to most efficiently metabolize food at high temperature.

Possibly the highest compliment one can pay a scientist is to describe her work as “elegant.” This is an elegant experiment.

4 Responses to “EVOLUTION AT WORK”


Comment by
Nance Confer
May 19th, 2006
at 9:06 am

Thanks for sharing this, Daryl. A nice way to start the day! 🙂

Nance


Comment by
Gary Petersen
May 19th, 2006
at 12:46 pm

I’ve not read their study, but the excerpt you quoted makes it sound like this is evidence that supports natural selection, not evolution. Nothing changed – no new information was created. “Eventually, one strain squeezed out almost all the competition”, but it appeared to be one strain that was there when the experiment started. It didn’t evolve. The fittest – or most suited for that environment – survived.


Comment by
Nance Confer
May 20th, 2006
at 4:57 pm

The summary gives a bit more info about the evolution/mutation part of the experiment. Which narrowed the field to the 6 bacteria left to battle our the survivial of the fittest —

Rice University biologists, using an ingenious experiment that forced bacteria to compete in a head-to-head contest for evolutionary dominance, today offer the first glimpse of how individual genetic-level adaptations play out as Darwinian natural selection in large populations. The results appear in the May 19 issue of Molecular Cell.

“One of our most surprising findings is that an estimated 20 million point mutations gave rise to just six populations that were capable of vying for dominance,” said lead researcher Yousif Shamoo, associate professor of biochemistry and cell biology. “This suggests that very few molecular pathways are available for a specific molecular response, and it points to the intriguing possibility of developing a system to predict the specific mutations that pathogens will use in order to become resistant to antibiotics.”


Comment by
Lioness
May 20th, 2006
at 7:21 pm

Neat. Dh designed a version of that experiment 14 years ago, but he was told then that no one was interested. I’m glad to see times have changed.