New Study Argues Life on Earth May Have Emerged Twice, Not Once

A paper in Science Advances proposes that the leap from non-living chemistry to living cells happened independently in the two deepest branches of life — bacteria and archaea — rather than a single time. The researchers ranked the protein structures of core metabolic enzymes by complexity across bacterial and archaeal genomes to reconstruct the order in which metabolism was built up. Their reading of the data: the enzymes catalyzing the same essential reactions are not shared across the bacteria–archaea divide, implying each lineage engineered its own path to independent, free-living existence. Lead author William Martin frames it as one origin of the genetic code but two origins of life.

The model describes catalysis developing in four phases. The last universal common ancestor (LUCA) is portrayed as only ‘half alive,’ running roughly half its reactions on naturally occurring metal catalysts in hydrothermal-vent environments and gradually replacing them with self-made enzymes. Only after bacteria and archaea diverged, the team argues, did either fully shed its dependence on environmental metals to become truly free-living. The authors also report a possible workaround for the ATP chicken-and-egg problem: phosphite plus palladium driving phosphorylation reactions in water without ATP or enzymes.

Editorial note: This is an origin-of-life biology story, entirely outside this publication’s cybersecurity and technology beat — it surfaced via Hacker News but is not a tech item. The claim is also contested (defining ‘life’ is itself disputed, and the reaction medium remains unknown), and the authors concede it needs further work. No valid tag from the approved list genuinely fits; the tags below are placeholders only and I recommend not publishing this piece here.