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Monday, November 30, 2009

Recreating the RNA World

RNA molecules are formed using nothing but water.

Abiogenesis is the study of how life began on earth. This is not to be confused with evolution, which explains how we came to have the current diversity of life. Evolution began once there were life forms reproducing and competing. But how did life originally arise? That is still not completely understood.

We do know a few things though, one of which is that RNA preceded DNA as the information carrying molecule. RNA is less stable than DNA, but it has the advantage of serving as both a vehicle for information storage and as a catalyst to make more RNA and even protein chains. The instability of RNA means that primitive life forms employing it would have had a much greater mutation rate. This might have been advantageous to life in the early stages when it was struggling to gain footholds (pseudopod holds?) on its environment. As soon as life discovered DNA, a much more stable molecule, RNA was abandoned as the primary information storage container.

This is all well and good, but how do you get RNA in the first place? Ernesto Di Mauro’s lab has been able to synthesize chains of RNA over 120 nucleotides long using only water. That’s right, no enzymes or inorganic catalysts, no radiation, no lightning bolts. And of course, once you have RNA and a few odds and ends like lipids, you can have primitive cells!