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Elongation factor-2: a useful gene for arthropod phylogenetics
1Center for Agricultural Biotechnology, University of Maryland Biotechnology Institute, Plant Sciences Building, College Park, Maryland 20742, USA. regier@glue.umd.edu
Molecular Phylogenetics and Evolution
|June 26, 2001
Summary
Molecular data, including elongation factor-2, strongly support Pancrustacea (Crustacea + Hexapoda) over Atelocerata (Myriapoda + Hexapoda). This challenges morphology-based analyses and highlights the need for further investigation into arthropod phylogeny.
Area of Science:
- Molecular Phylogenetics
- Arthropod Systematics
- Evolutionary Biology
Background:
- Resolving higher-level evolutionary relationships within Arthropoda has been challenging due to conflicting data.
- Morphological analyses have proposed the group Atelocerata (Myriapoda + Hexapoda), which is debated.
- Additional molecular data are needed to clarify arthropod evolutionary history.
Purpose of the Study:
- To investigate the phylogenetic position of major arthropod groups using new molecular data.
- To compare phylogenetic signals from different nuclear protein-encoding genes.
- To resolve the controversial relationship between Myriapoda, Hexapoda, and Crustacea.
Main Methods:
- Sequencing of elongation factor-2 (EF-2) gene from 17 arthropod taxa and outgroups.
- Phylogenetic analyses using likelihood and parsimony on nucleotide and amino acid datasets.
- Comparison with existing sequences from RNA polymerase II and elongation factor-1alpha.
Main Results:
- EF-2 analyses consistently supported Myriapoda and Chelicerata monophyly with high bootstrap support.
- Pancrustacea (Crustacea + Hexapoda) was recovered with moderate support; Atelocerata was never recovered.
- Combined analyses of three nuclear genes strongly supported Pancrustacea, Chelicerata, Myriapoda, and other accepted clades.
Conclusions:
- Elongation factor-2 provides molecular evidence supporting Pancrustacea over Atelocerata.
- The molecular data contradict some morphology-based hypotheses, particularly regarding Atelocerata.
- Discrepancies between molecular and morphological data in arthropod phylogeny warrant further attention.