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Updated: Jun 28, 2026
09:38
Embryo Microinjection and Electroporation in the Chordate Ciona intestinalis
Published on: October 16, 2016
Additional molecular support for the new chordate phylogeny.
Frédéric Delsuc1, Georgia Tsagkogeorga, Nicolas Lartillot
1Institut des Sciences de l'Evolution, UMR5554-CNRS, Université Montpellier II, CC064, Place Eugène Bataillon, Montpellier Cedex 5, France. frederic.delsuc@univ-montp2.fr
Genesis (New York, N.Y. : 2000)
|November 13, 2008
Summary
Tunicates, not cephalochordates, are the closest relatives of vertebrates, according to new phylogenomic data. This finding supports the Olfactores hypothesis, clarifying chordate evolution.
Area of Science:
- Evolutionary Biology
- Genomics
- Phylogenetics
Background:
- Phylogenetic analyses suggest tunicates are closer to vertebrates than cephalochordates.
- This challenges the traditional view of Euchordate relationships.
- Previous hypotheses faced skepticism.
Purpose of the Study:
- To resolve the phylogenetic position of tunicates relative to vertebrates and cephalochordates.
- To test the Olfactores hypothesis using an expanded dataset.
- To clarify chordate evolutionary history.
Main Methods:
- Assembled an expanded phylogenomic dataset of deuterostomes.
- Utilized maximum-likelihood and Bayesian phylogenetic analyses.
- Incorporated site-heterogeneous mixture models and ribosomal RNA analyses.
Main Results:
- Unequivocal support for a sister-group relationship between tunicates and vertebrates (Olfactores).
- Chordates were monophyletic, with cephalochordates as the most basal lineage.
- Results were robust to gene sampling and missing data.
Conclusions:
- The tunicate-vertebrate sister-group relationship (Olfactores) is strongly supported.
- Chordate monophyly is confirmed with cephalochordates as basal.
- Findings impact interpretations of chordate evolution, integrating developmental biology and genomics.
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