This review will cover all these aspects, from the first life on Earth to Homo sapiens.Linked in figure 1 is a high-resolution image of the evolutionary tree of life, from viruses through bacteria and archaea to protista, plants, animals and fungi, with a selection of representative species illustrated.As shown above left, this enzyme has an evolutionary tree extending back to LUCA confirming the obvious - that the genetic code cannot exist without the 21st software engineered amino acid selenocysteine!
RU XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX. Fig 1c2: Left: Evolutionary tree of selenophosphate synthetase (Romero et al. Centre: SECIS hairpins of archaea (A), bacteria (B) and corresponding eukaryote variants (C, D) (Moldave ed 2006).Top right: Tertiary structure of SECIS showing highly conserved regions (hot) (Walczak et al. Lower right: SECIS acts as an RNA-enzyme to attach the selenocysteine t-RNA to the nascent protein (click to enlarge).I have updated and amended this several times as new research has clarified specific parts of the trunk and branches.The evolutionary tree of life is our immortal progenitor, not just of ourselves, but of all the species with which we co-depend, so we need to both understand it and protect it for the future generations.Terminal oxidases belonging to oxygen, nitrate, sulfate, and sulfur respiratory pathways have been sequenced in members of both bacteria and archaea including cytochrome oxidase, nitrate reductase, adenylylsulfate reductase, sulfite reductase, and polysulfide reductase which can likewise be assigned to LUCA (Castresana & Moreira 1999).