New research suggests bacteria and archaea originated from separate life-forming events

Researchers publishing in Science Advances contend that life’s earliest split into bacteria and archaea did not stem from a single living ancestor but from two independent transitions out of a metal-driven chemical network in hydrothermal vents. They describe the Last Universal Common Ancestor as a cluster of RNA, DNA and vent-derived enzymes that relied on metals to synthesize basic building blocks. Comparative genome analysis revealed that each domain retains only roughly fifty percent of the enzymes needed for core metabolic pathways, implying separate evolutionary routes to self-sustaining cells.

Experiments in the authors' lab showed that palladium can catalyze a vital conversion of phosphite to phosphate, illustrating how geological catalysts could have powered early metabolism. The study’s senior author, evolutionary biologist William Martin, and first author Natalia Mrnjavac suggest that these parallel developments eventually gave rise to modern bacteria and archaea. Independent commentary from NASA astrobiology director Betül Kaçar notes that while the findings are plausible, they do not yet explain the full handoff from chemistry to biology, and further testing is required.