"LUCA" . . "shared ancestry" . "Last universal common ancestor#Hypotheses" . "a single common ancestor" . "common ancestor" . . "last universal common ancestor" . . "last common ancestor of all current life" . . "last universal common ancestor (LUCA)" . . "Last Universal Common Ancestor" . "Last universal common ancestor" . "universal common descent" . "ancient common ancestor" . "Last universal common ancestor" . . "Luca" . . .