Catherine Brahic (based on research by Ernesto Di Mauro, Sapienza University of Rome)
New Scientist, April 24 2010
A team led by Ernesto Di Mauro at Sapienza University of Rome may point a way to solving the problem of the origin of life on Earth. It is thought most likely that life developed from RNA replicators. The problem here has been as to how the first replicator emerged, with an impossibly high probability against the molecules of the first replicator arranging themselves in a chain of the right order simply by chance. The nucleotides that make up RNA do not tend to form chains without a catalyst, but the catalysts that act to produce such chains are proteins, which are themselves made by RNA. This creates a classic chicken and egg conundrum, but long before there were either chickens or eggs on Earth.
However, experiments by Di Mauro’s team suggest a possible solution. They have shown that cyclic nucleotides, a chemical variation of the nucleotides that make up RNA, can join up to form RNA chains. The ‘black smoker’ hydrothermal vents in the oceans are seen as suitable locations for this to happen, although this step has not been experimentally tested.
It will be interesting to see whether this theory can establish itself as an orthodox explanation for the emergence of the first replicators. If it’s as simple as all that, it would seem to suggest the near certainty of some form of life on Earth-like planets elsewhere in the universe.