How did life’s myriad parts come together? At a minimum, the first life forms on Earth needed a way to store information and replicate. Only then could they make copies of themselves and spread across the world.
One of the most influential hypotheses states that it all began with RNA, a molecule that can both record genetic blueprints and trigger chemical reactions. The “RNA world” hypothesis comes in many forms, but the most traditional holds that life started with the formation of an RNA molecule capable of replicating itself. Its descendants evolved the ability to perform an array of tasks, such as making new compounds and storing energy. In time, complex life followed.
However, scientists have found it surprisingly challenging to create self-replicating RNA in the lab. Researchers have had some success, but the candidate molecules they have manufactured to date can only replicate certain sequences or a certain length of RNA. Moreover, these RNA molecules are themselves quite complicated, raising the question of how they might have formed through chance chemical means.
Nick Hud, a chemist at the Georgia Institute of Technology, and his collaborators are looking beyond biology to the role of chemistry in the development of life. Perhaps before biology arose, there was a preliminary stage of proto-life, in which chemical processes alone created a smorgasbord of RNAs or RNA-like molecules. “I think there were a lot of steps before you get to a self-replicating self-sustaining system,” Hud said.