Atomic-resolution structure of a ribozyme yields insights into RNA catalysis and the origins of life

Which came first, nucleic acids or proteins? This question is molecular biology's version of the "chicken-or-the-egg" riddle. Genes made of nucleic acids (DNA or RNA) contain the instructions for making proteins, but enzymes made of proteins are needed to replicate genes. For those who try to understand how life originated, this once seemed an intractable paradox.