William Martin

“These comparisons are giving us unprecedented insights into the phase of evolution when metabolism catalyzed by enzymes was arising from spontaneous reactions catalyzed by metals in the Earth's crust,”

William Martin · said date not stated · reported 2026-08-05

Martin comments on insights from comparisons of genomes, protein structures, and chemical reactions probing early microbial evolution.

“The surprise is that the enzymes that catalyze those reactions are not conserved across the evolutionary divide that separates bacteria and archaea. We found that the last universal ancestor of all cells, LUCA, possessed enzymes for only about half of the reactions of metabolism. The other half was catalyzed by metals in the environment where LUCA arose.”

William Martin · said date not stated · reported 2026-08-05

Martin explains that enzymes catalyzing metabolic reactions are not conserved across the bacterial-archaeal divide and that LUCA possessed enzymes for only half of metabolism.

“The new data leave only one conclusion. The bacterial and archaeal lineages made the transition to the free-living state independently. Only free-living cells are alive. Let's call it by name: We are looking at one origin of the genetic code, but two origins of life.”

William Martin · said date not stated · reported 2026-08-05

Martin concludes that bacterial and archaeal lineages independently transitioned to free-living states, implying two origins of life but one origin of the genetic code.