Life's first instruction manual was just found in old molecules

A new paper suggests the genetic code, which tells cells how to build proteins, might have started with simple transfer RNA molecules. These molecules seem to hold clues about how different amino acids were added to life's instruction set over billions of years.

Scientists have long debated how the genetic code first appeared. This paper offers a specific idea for how that process unfolded. It links the code's evolution to the structure of existing molecules, which could help explain a fundamental mystery of life.