Freeman Dyson- LIFE: WHAT A CONCEPT!

"The essential idea is that you separate metabolism from replication. We know modern life has both metabolism and replication, but they're   carried out by separate groups of molecules. Metabolism is carried out by proteins and all kinds of other molecules, and replication is carried out by DNA and RNA. That maybe is a clue to the fact that   they started out separate rather than together. So my version of the origin of life is that it started with metabolism only."