Study finds bacteria and archaea evolved separately from shared LUCA using hydrothermal vent chemistry

Researchers led by biologist Natalia Mrnjavac at Heinrich Heine University Düsseldorf published a study in Science Advances that reconstructs the metabolic history of the last universal common ancestor (LUCA). By analysing genomes, protein structures and 361 core metabolic reactions from 552 bacterial and 401 archaeal isolates, they identified 166 core enzymes present in LUCA, with 89 later added in the bacterial lineage and 38 in the archaeal lineage. The authors argue that native metals in hydrothermal vents—iron, nickel, cobalt and palladium—served as early catalysts before modern enzymes evolved.

The analysis suggests that while bacteria and archaea share a common genetic code inherited from LUCA, they completed the transition to free‑living cells along separate evolutionary paths, each developing distinct enzyme sets to finish essential chemical work. “We would see two very different kinds of cells emerging, pioneer bacteria and pioneer archaea, making their first attempts at life outside the confines of a hydrothermal vent,” Mrnjavac said.