The origin of life

If I were to ask you to think of something living and something inanimate, you would probably be thinking of two very different things. There’s a gulf of complexity between you and the chair you are (perhaps) sitting on, between a mountain and the tree growing on its slopes.

But despite the complexity of life compared with the relative simplicity of inanimate objects, if we zoom in on the line that divides the two, we find it’s blurrier than our macroscopic world suggests.

Viruses, for example, are distinctly biological. They have a genome and a protein capsid. Some are even enveloped in a lipid membrane. And they evolve, just like living organisms. But they are not alive. Well, most biologists agree they are not alive – it really depends where you draw the line. Viruses can’t self-replicate – a key feature of living organisms – they require a host cell to do the work of replication for them.

This blurry line has fascinated chemists for decades. You see, somewhere in Earth’s history a collection of barely inanimate molecules crossed that threshold and became a living organism, and we want to know what it looked like and how it came into existence.

Paul MacLellan investigates how molecules turned into living organisms, from the first bright spark to making life.