Bacteria and archaea evolved separately, hinting life began twice at hydrothermal vents

A new study suggests bacteria and archaea may have independently evolved from non-living matter, implying life on Earth arose twice rather than once. Researchers found enzymes in bacteria and archaea performing identical chemical reactions have different origins. Co-author William Martin said the genetic code may have emerged once, but life itself twice, challenging the traditional single-origin view. Early metabolism may have depended on natural metals in ocean hydrothermal vents, with phosphite possibly replacing ATP as an energy source. The authors stress this remains a hypothesis needing further research.