Predation between prokaryotes and the origin of eukaryotes.

Area of Science:

• Cell Biology
• Evolutionary Biology
• Microbiology

Background:

• The prevailing theory suggests eukaryotic cells evolved from a symbiotic merger between an archaeal host and a bacterial endosymbiont.
• Prokaryotes lack phagocytosis, posing a challenge to understanding how the endosymbiont entered its host cell.

Purpose of the Study:

• To propose a novel model for the origin of the eukaryotic cell.
• To explain the mechanism of endosymbiont acquisition by the host cell.

Main Methods:

• A theoretical model is presented, proposing a predatory or parasitic interaction.
• The model outlines the characteristics of the proposed archaeal host and alpha-proteobacterial endosymbiont.

Main Results:

• The model suggests an anaerobic archaeal host with a periplasm-like space.
• A facultative aerobic alpha-proteobacterium is proposed as the endosymbiont that penetrated the host's periplasm.
• This interaction led to the bacterium becoming the mitochondrion.

Conclusions:

• Predatory or parasitic interactions offer a plausible explanation for endosymbiont entry into prokaryotic hosts.
• This model provides a framework for understanding the conditions and events leading to the complex eukaryotic cell.
• The proposed mechanism addresses the enigma of endosymbiont acquisition in early cell evolution.