Novel molecular fossils of bacteria: Insights into hydrothermal origin of life

► The anhydro bond of the cell wall peptidoglycan is a thermal bond. ► Biochemical process of life was imprinted by the heritage of alkaline submarine vents. ► Proteins of life were imprinted by the heritage of alkaline submarine vents. ► Dnd phenotype is a response to prebiotic soups near by alkaline submarine vents. ► Sulfur-modified DNA and the anhydro bond of peptidoglycan are molecular fossils of alkaline submarine vents.