Multigene phylogeny resolves deep branching of Amoebozoa

Area of Science:

• Eukaryotic Phylogeny
• Evolutionary Biology
• Molecular Systematics

Background:

• The phylogenetic validity of the Amoebozoa phylum has been debated due to the high diversity of included species.
• Previous phylogenetic analyses using 18S rRNA genes have failed to firmly establish the internal topology of Amoebozoa.

Purpose of the Study:

• To resolve the phylogenetic relationships and establish the monophyly of Amoebozoa.
• To clarify the internal structure and evolutionary history of the Amoebozoa phylum.

Main Methods:

• Sequencing of cDNA libraries from seven diverse Amoebozoa species.
• Phylogenetic analyses of 109 eukaryotes, including 17-18 Amoebozoa, using 60-188 genes.
• Bayesian inferences with the CAT-GTR-Γ model and maximum likelihood analyses were employed.

Main Results:

• Unequivocal establishment of Amoebozoa monophyly.
• A primary dichotomy was identified between the subphyla Lobosa (non-flagellate amoebae) and Conosa.
• Lobosa was robustly partitioned into Tubulinea and Discosea; Conosa showed a dichotomy between Semiconosia (Mycetozoa, Variosea) and Archamoebae.

Conclusions:

• The study provides strong phylogenetic support for the monophyly and internal classification of Amoebozoa.
• Findings align with classifications based on locomotion, pseudopodial morphology, and ultrastructure.
• Potential tree reconstruction artifacts due to missing data were noted for Archamoebae placement in some analyses.