What Is The Metabolism‑First Hypothesis For The Origin Of Life?

Find out what the study of cellular metabolism is teaching us about the origin of life, and what a deeper study of metabolism might reveal.



While most origin of life researchers are focused on the evolution of self-replicating macromolecules (either gene-like structures or protein-like structures as we covered in our video about the RNA world hypothesis), other scientists believe that before macromolecules could originate, some aspect of modern cellular metabolism must have been present.

There are two main “Metabolism-First” hypotheses. Both concepts are based on the idea that some aspect of modern metabolism existed before the first macromolecules and helped to produce them:

Proto metabolic cycles (referred to in the literature as “autocatalytic sets”) are cyclical reactions that can grow. When 2 simple autocatalytic sets merge, they can develop new traits, some of which may help in their survival. It is proposed that autocatalytic sets may be capable of type of open-ended evolution and eventually gave rise to evolving macromolecules and then life as we know it.

Metabolic “fossils” can be found in modern metabolisms. Their study can reveal the chemical nature of the environment that first generated life, allowing us to simulate that environment and perhaps witness life’s re-emergence in the lab.

This animation is a follow up to the video “What is Metabolism?”.

Explore Further

Scientific papers on metabolic fossils (shown in this animation)

Early work attempting to piece together a primitive metabolism from the study of modern metabolisms

Scientific papers on autocatalytic sets

Video lecture on autocatalytic sets

Popular Article on the general idea of metabolism-first