Recent research by University of North Carolina scientists sheds new light on the transition from building blocks into life some 4 billion years ago. The study shows that the close linkage between the physical properties of amino acids, the genetic code, and protein folding was likely essential from the beginning, long before large, sophisticated molecules arrived on the scene. The findings fly in the face of the problematic 'RNA world' theory and add a new layer to the story of how life evolved billions of years ago.