Since the discovery that RNA molecules can act as catalysts in chemical reactions, they have become prime candidates for being the kick start that life on Earth need billions of years ago. Although the conventional explanation is that proteins were cooked up in the primordial oceans and ultimately became parts of living organisms, there is no clear way to get from proteins appearing randomly to self-organising systems based on proteins.
Although proteins can make efficient catalysts, they have no clear way to reproduce. RNA is now a much more likely candidate as it can pass on genetic information and catalyse the reactions needed to do it. Although proteins are now responsible for most of the body’s catalysis, RNA ‘ribozymes’ are still in active and can be found at the heart of what are understood to be some of the most ancient cellular functions.