An alternative root for the eukaryote tree of life

Area of Science:

• * Evolutionary Biology
• * Phylogenetics
• * Molecular Biology

Background:

• * The root of the eukaryote tree of life is crucial for understanding fundamental species relationships and the Last Eukaryote Common Ancestor (LECA).
• * The dominant unikont-bikont root model has faced increasing controversy.
• * Accurate eukaryotic phylogeny is essential for evolutionary studies.

Purpose of the Study:

• * To develop a robust phylogenetic analysis to resolve the eukaryotic root.
• * To challenge the existing unikont-bikont paradigm with new data and analysis.
• * To investigate the evolutionary position of Discoba within eukaryotes.

Main Methods:

• * Creation of a curated dataset of 37 nuclear-encoded proteins (euBacs) and their bacterial relatives.
• * Deep sequencing of the Acrasis kona (Discoba) transcriptome.
• * Phylogenetic analysis using robust computational methods.

Main Results:

• * A highly resolved global eukaryote phylogeny was generated.
• * Eukaryotes were sorted into three megagroups.
• * The Discoba (or Excavata) was identified as the sister group to Neozoa (Amorphea + SARP).

Conclusions:

• * The study supports a novel