Twenty different lines of polyphasic evidence obtained from tRNA and protein sequences, anticodon usages, gene contents, metabolism and geochemistry have made possible the identification of a Last Universal Common Ancestor (LUCA) phylogenetically located proximal to the hyperthermophilic methanogenic archaeon Methanopyrus. Combined with analysis of high-similarity cross-domain tRNA pairs, the evidence also suggests a Thermotoga-proximal Last Bacterial Common Ancestor (LBACA) that originated from Crenarchaeota close to Aeropyrum, and a Plasmodium-proximal Last Eukaryotic Common Ancestor (LECA) derived from Ferroplasma through endosymbiosis.