Within the past few years, neat scheme has been overturned by the discovery that RNA can act as an enzyme. What does the starting finding of RNA enzymes imply? Thre first implication is that one can no longer assume a protein lies behind every catalytic activity of the cell. It now appears that several of the operations that tailor an RAN molecule into its final form are at least in part catalyzed by RNA. The finding that RNA can be a catalyst as well as an informational molecule suggests that when life originated, RNA may have functioned without DNA or proteins.

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