Suggested timing of key evolutionary events based on a schematic ribosomal species tree. Abbreviations:
LUCA, last universal common ancestor;
LACA, last archaeal common ancestor;
LBCA, last bacterial common ancestor;
LECA, last eukaryotic common ancestor;
MAnc, shared ancestor of mitochondria and closest alphaproteobacterial sister lineage;
AAnc, shared ancestor of eukaryotic host lineage and close asgardarchaeal sister lineage;
Hod, Hodarchaeales;
PAnc, shared ancestor of plastid and closest cyanobacterial sister lineage;