The emergence of complex biological molecules, long before the first cells, is one of the most mysterious chapters in the origins of life story. One popular theory suggests that RNA—the more active, single stranded version of DNA—came on the scene first, making copies of itself and building the first proteins. But new research, which appears this week in the Proceedings of the National Academies of Sciences, refutes the idea that RNA alone jumpstarted life. Rather, RNA and peptides, the amino acid chains that build proteins, probably co-created each other.