Archaea and the prokaryote-to-eukaryote transition

Area of Science:

• Evolutionary biology
• Microbial genomics
• Phylogenetics

Background:

• Determining phylogenetic relationships among Archaea, Bacteria, and Eucarya is crucial for understanding early cellular evolution.
• Key questions involve the monophyletic nature of these domains and the root of the universal tree of life.
• The evolutionary status of Archaea is central to resolving these questions.

Purpose of the Study:

• To review cumulative knowledge on Archaea in relation to Bacteria and Eucarya.
• To highlight the application of molecular phylogenetic approaches in reconstructing the tree of life.
• To analyze protein-based phylogenetic analyses within the context of biochemical pathways.

Main Methods:

• Review of phylogenetic analyses of over 60 proteins.
• Examination of protein participation in major biochemical pathways.
• Assessment of gene tree incongruence and potential interdomain gene transfer.

Main Results:

• The majority of gene trees suggest a sisterhood relationship between Archaea and Eucarya.
• Incongruent gene trees indicate complexities in evolutionary history.
• Two types of interdomain gene transfer are identified as potential modifiers of evolutionary patterns.

Conclusions:

• The Archaea domain's position is key to understanding the universal tree of life.
• Molecular phylogenetics provides insights into the relationships between the three domains.
• Horizontal gene transfer events may have influenced the evolutionary trajectories of Archaea, Bacteria, and Eucarya.