What powered the Earth's earliest life?

Early biological systems likely relied on RNA molecules to copy themselves and drive simple chemical reactions. Any system that could generate guanosine-triphosphate (GTP)—which is necessary for RNA synthesis—from prebiotic chemicals would gain a crucial advantage toward self-replication. Now, researchers from the University of California San Diego report a version of an RNA enzyme (ribozyme) that makes GTP synthesis more efficient than its predecessor.