Sunday, February 08, 2009

It's (Almost) Alive!

Life in a test tube? Coming right up ...

Way back when I was taking high school biology our text book described an intriguing experiment where a scientist had cooked up a laboratory version of the primordial soup in which life was supposed to have originated. After heating it and zapping it with artificial lightning bolts in a piece of sealed glassware, he examined the results and discovered that primitive amino acids -- the building blocks of proteins, and eventually DNA -- had been formed. It was easy to imagine that we were only a few steps away from creating "life in a test tube," one of the big dreams of science fiction buffs everywhere.

The reality has turned out to be a bit trickier. Even though we have learned a great deal more about how cells work, and even though we have decoded DNA and begun to play with it like a set of tinker-toys to create new combinations, we don't seem to be a lot closer to actually creating living organisms from inanimate chemicals.

But now in this article New Scientist reports a further breakthough on the road to discovering how life may have originated. Beginning with a synthetic molecule they created themselves, with the ability to assemble a copy of itself from short segments of RNA, they were able to show a working model of a self-replicating molecular unit which, while not quite alive, fulfills one of life's primary functions, and may be an example of the kind of step that preceeded the first living organisms.

Even more fascinating, they were able to demonstrate a low level form of evolution by allowing competing molecules to vie with each other for available raw materials. Those with the best ability to make copies of themselves soon dominated the others.

This marvelously simple demonstration of the power of natural selection shows how the process may have played a key role even in the original formation of life from proto-organic compounds. Once again we must stand in awe of a cosmos in which this drive toward life and higher consciousness appears to be built into the most fundamental laws, leading with inevitability from atoms to stars, stars to planets, simple molecules to life, and life to intelligence.

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