Deuterostome phylogeny reveals monophyletic chordates and the new phylum Xenoturbellida

@article{Bourlat2006DeuterostomePR,
  title={Deuterostome phylogeny reveals monophyletic chordates and the new phylum Xenoturbellida},
  author={Sarah J. Bourlat and Thorhildur Juliusdottir and Christopher J. Lowe and Robert M. Freeman and Jochanan Aronowicz and Mark Kirschner and Eric S. Lander and Michael C. Thorndyke and Hiroaki Nakano and Andrea B. Kohn and Andreas Heyland and Leonid L. Moroz and Richard R. Copley and Maximilian J. Telford},
  journal={Nature},
  year={2006},
  volume={444},
  pages={85-88}
}
Deuterostomes comprise vertebrates, the related invertebrate chordates (tunicates and cephalochordates) and three other invertebrate taxa: hemichordates, echinoderms and Xenoturbella. The relationships between invertebrate and vertebrate deuterostomes are clearly important for understanding our own distant origins. Recent phylogenetic studies of chordate classes and a sea urchin have indicated that urochordates might be the closest invertebrate sister group of vertebrates, rather than… 
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491 Citations
Highly Influential Citations
28
Background Citations
212
Methods Citations
25
Results Citations
21

491 Citations

Deciphering deuterostome phylogeny: molecular, morphological and palaeontological perspectives
  • B. SwallaA. Smith
  • Biology
    Philosophical Transactions of the Royal Society B: Biological Sciences
  • 2008
TLDR
Molecular phylogenies, larval morphology and the adult heart/kidney complex all support echinoderms and hemichordates as a sister grouping (Ambulacraria), andGene network data suggest that the ancestral deuterostome ancestor had an anterior–posterior body axis specified by Hox and Wnt genes, and was bilaterally symmetrical with left–right asymmetry determined by expression of nodal.
Revaluation of deuterostome phylogeny and evolutionary relationships among chordate subphyla using mitogenome data.
Chordate evolution and the three-phylum system
TLDR
It is proposed that an evolutionary occurrence of tadpole-type larvae is fundamental to understanding mechanisms of chordate origin and should be classified at the superphylum level, with the Chordata further subdivided into three phyla, on the basis of their distinctive characteristics.
Phylogenomic Resolution of the Hemichordate and Echinoderm Clade
Hemichordate genomes and deuterostome origins
TLDR
The draft genome sequences of two acorn worms are reported, identifying shared traits that were probably inherited from the last common deuterostome ancestor, and exploring evolutionary trajectories leading from this ancestor to hemichordates, echinoderms and chordates.
Hemichordate genomes and deuterostome origins
TLDR
This work reports the draft genome sequences of two acorn worms, Saccoglossus kowalevskii and Ptychodera flava, and identifies shared traits that were probably inherited from the last common deuterostome ancestor, and explores evolutionary trajectories leading to hemichordates, echinoderms and chordates.
Crinoidea Echinoidea Holothuroidea Asteroidea Ophiuroidea Pterobranchia Ptychoderidae Xenoturbellida Cephalochordata Vertebrata Harrimaniidae Appendicularia Phlebobranchia Thaliacea Aplousobranchia Stolidobranchia Molgulidae
TLDR
Molecular phylogenies, larval morphology and the adult heart/kidney complex all support echinoderms and hemichordates as a sister grouping (Ambulacraria), andGene network data suggest that the ancestral deuterostome ancestor had an anterior–posterior body axis specified by Hox and Wnt genes, and was bilaterally symmetrical with left–right asymmetry determined by expression of nodal.
Xenacoelomorph-Specific Hox Peptides: Insights into the Phylogeny of Acoels, Nemertodermatids, and Xenoturbellids
TLDR
Results from the decoded genome of the acoel Praesagittifera naikaiensis and reported xenacoelomorph Hox genes revealed that acoels share a peptide NLK(S/T)MSQ(V/I)D, which starts immediately after the homeodomain sequence of the central Hox4/5/6.
Molecular phylogeny of hemichordata, with updated status of deep-sea enteropneusts.
Acoelomorph flatworms are deuterostomes related to Xenoturbella
TLDR
This phylogeny makes sense of the shared characteristics of Xenoturbellida and Acoelomorpha, and implies the loss of various deuterostome characters in the Xenobiology including coelomic cavities, through gut and gill slits.
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References

SHOWING 1-10 OF 39 REFERENCES
Tunicates and not cephalochordates are the closest living relatives of vertebrates
TLDR
It is shown that phylogenetic analyses of the genome sequencing of the appendicularian Oikopleura dioica provide compelling evidence that tunicates, and not cephalochordates, represent the closest living relatives of vertebrates.
Deuterostome phylogeny and the sister group of the chordates: evidence from molecules and morphology.
TLDR
The results illustrate both the limitations of the 18S rRNA molecule alone for high-level phylogeny inference and the importance of considering both molecular and morphological data in phylogeny reconstruction.
Xenoturbella is a deuterostome that eats molluscs
TLDR
It is shown that the samples in these studies were contaminated by bivalve embryos eaten by Xenoturbella and that XenOTurbella is in fact a deuterostome related to hemichordates and echinoderms.
Multigene analyses of bilaterian animals corroborate the monophyly of Ecdysozoa, Lophotrochozoa, and Protostomia.
TLDR
This study demonstrates that the incongruences observed between rRNA and multigene analyses were indeed due to long-branch attraction artifacts, illustrating the enormous impact of systematic biases on phylogenomic studies and suggests that urochordates are more closely related to vertebrates than are cephalochordates.
Key characters uniting hemichordates and chordates: homologies or homoplasies?
TLDR
A cladistic analysis of Deuterostomia, based partly on homologs discussed in this paper, indicates a sister-taxon relationship between Urochordata and Vertebrata, with Cephalochordata as the plesiomorphic clade.
The phylogenetic affinities of the chaetognaths: a molecular analysis.
TLDR
This work proposes that the lineage leading to the chaetognaths arose prior to the advent of the coelomate metazoa, and isolation and nucleotide sequence determination of 18S ribosomal DNA from one species of Chaetognath and one acanthocephalan are described.
Evolution and development of the chordates: collagen and pharyngeal cartilage.
TLDR
The evidence suggests that the deuterostome ancestor was a benthic worm with gill slits and acellular gill cartilages and the development of chordate characters in hemichordates is reviewed and new data is presented characterizing the pharyngeal gillslits and their cartilaginous gill bars.
A novel amphioxus cadherin that localizes to epithelial adherens junctions has an unusual domain organization with implications for chordate phylogeny
TLDR
It is argued that BbC is the amphioxus homologue of the classic cadherins involved in the formation of epithelial adherens junctions, and a possibility that cephalochordates might be basal to the sister‐groups vertebrates and urochordates.
The ciliated epidermis of Xenoturbella bocki (Platyhelminthes, Xenoturbellida) with some phylogenetic considerations
TLDR
The epidermis of Xenoturbella bocki Westblad was studied by scanning and transmission electron microscopy and showed a characteristic pattern of axonemal filament termination in the distal tips of their cilia, which may be an apomorphic feature which indicates a close relationship between xenoturbellida, Nemertoder‐matida and Acoela.
Nerve cells of Xenoturbella bocki (phylum uncertain) and Harrimania kupfferi (Enteropneusta) are positively immunoreactive to antibodies raised against echinoderm neuropeptides
TLDR
The presence of immunoreactivity against S2 can be interpreted as a synapomorphy of Enteropneusta, Echinodermata, and Xenoturbella spp.
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