Some theories to explain the origin of the eukaryotic cell
Back to main indexThere are several theories trying to explain the origin of the eukaryotic cell and its relationship to prokaryotic cells. None are satisfactory to date because each explains part of the story but does not account for all of the attributes of the eukaryotic cell. These theories can be classified into several groups (Figure 18): those which assume that (1) the three groups of living beings have an independent origin, (2) prokaryotes and eukaryotes derive from a common ancestor, the Last Universal Common Ancestor or LUCA, mainly by simplification for prokaryotes complexification for eukaryotes, LUCA possibly having been a “proto-eukaryote”, (3) eukaryotes derive from prokaryotes by fusion and/or endosymbiosis mechanisms.
Figure 18.
The three main groups of theories to explain the origin of eukaryotes.