The mitochondrial DNA of Xenoturbella bocki: genomic architecture and phylogenetic analysis

  title={The mitochondrial DNA of Xenoturbella bocki: genomic architecture and phylogenetic analysis},
  author={Marleen Perseke and Thomas Hankeln and Bettina Weich and Guido Fritzsch and Peter F. Stadler and Olle Israelsson and Detlef Bernhard and Martin Schlegel},
  journal={Theory in Biosciences},
The phylogenetic position of Xenoturbella bocki has been a matter of controversy since its description in 1949. We sequenced a second complete mitochondrial genome of this species and performed phylogenetic analyses based on the amino acid sequences of all 13 mitochondrial protein-coding genes and on its gene order. Our results confirm the deuterostome relationship of Xenoturbella. However, in contrast to a recently published study (Bourlat et al. in Nature 444:85–88, 2006), our data analysis… 

The mitochondrial genome structure of Xenoturbella bocki (phylum Xenoturbellida) is ancestral within the deuterostomes

The mitochondrial genome of Xenoturbella bocki has a very conserved gene arrangement in the deuterostome group, strikingly similar to that of the hemichordates and the chordates, and thus to the ancestral deuterstome gene order.

PCR survey of Xenoturbella bocki Hox genes.

A polymerase chain reaction survey of partial Hox homeobox sequences of X. bocki did not find evidence for more than five Hox genes, one clear labial/PG1 ortholog, one posterior gene most similar to the PG9/10 genes of Ambulacraria, and three central group genes whose precise assignment to a specific paralog group remains open.

The phylogenetic position of Acoela as revealed by the complete mitochondrial genome of Symsagittifera roscoffensis

The phylogenetic analysis supports the view that acoels and nemertodermatids are the earliest divergent extant lineage of Bilateria and remain a valid source for seeking primitive characters present in the last common ancestor of Bilatersia.

The enigmatic mitochondrial genome of Rhabdopleura compacta (Pterobranchia) reveals insights into selection of an efficient tRNA system and supports monophyly of Ambulacraria

A strong reversed asymmetrical mutational constraint in the mitochondrial genome of Rhabdopleura compacta may have arisen by an inversion of the replication direction and adaptation to this bias in the protein sequences leading to an enigmatic mitochondrial genome.

Xenacoelomorpha flatworms are basal Deuterostome

This work sequence Heterochaerus australis’s mitochondrial genome and infer intrinsic relationships of Metazoan with Xenacoelomorpha and finds the optimal tree under the popular maximum likelihood (ML) and Bayesian phylogenetic reconstructions are consensus with each other being strongly supported.

Molecular approaches for studying the evolution of the Xenacoelomorpha

Gen visualisation protocols are developed and applied to investigate the expression patterns of genes commonly associated with ultrafiltration in Xenoturbella and the acoel Symsagittifera roscoffensis to shed light on the origin and homology of filtratory structures, which remain unclear.

Xenoturbellida: The fourth deuterostome phylum and the diet of worms

The phylogenetic position for Xenoturbella is considered in the light of what is known of its genetics, morphology, and ontogeny and what light this might shine on the common ancestor of the deuterostomes and hence on the origins of the chordates.

Correction to: A new species of Xenoturbella from the western Pacific Ocean and the evolution of Xenoturbella

The authors describe the two xenoturbellids as a new species again in this correction article.

The mitochondrial genomes of the acoelomorph worms Paratomella rubra and Isodiametra pulchra

Acoels are small, ubiquitous, but understudied, marine worms with a very simple body plan. Their internal phylogeny is still in parts unresolved, and the position of their proposed phylum



Xenoturbella 's molluscan relatives⃛

DNA sequence data are presented that place X. bocki within the protostome clade Eutrochozoa, and place it as the sister taxon of the Bilateria.

Poriferan mtDNA and animal phylogeny based on mitochondrial gene arrangements.

This work determined complete mitochondrial DNA sequences for the demosponges Geodia neptuni and Tethya actinia, two representatives of the most basal animal phylum, the Porifera, and provides strong support for a group that includes protostome (but not deuterostome) coelomate, pseudocoelomates, and acoelomating animals, thus clearly rejecting the Coelomata hypothesis.

Alignments of mitochondrial genome arrangements: applications to metazoan phylogeny.

The mitochondrial genome of the hemichordate Balanoglossus carnosus and the evolution of deuterostome mitochondria.

The complete nucleotide sequence of the mitochondrial genome of the hemichordate Balanoglossus carnosus (acorn worm) was determined, andylogenetic trees estimated from the inferred protein sequences indicate that hemichordsates are a sister group of echinoderms.

Codon reassignment and amino acid composition in hemichordate mitochondria.

The hemichordate mitochondrial genome can be regarded as an intermediate in the process of reassignment of mitochondrial AAA codons, where most metazoans represent the ancestral situation and the echinoderms the derived situation and support to the codon capture hypothesis.

Evolution of the Mitochondrial Genome in Cephalochordata as Inferred from Complete Nucleotide Sequences from Two Epigonichthys Species

The present analysis suggested that AGR codons in lancelet mtDNA were likely to correspond to serine residue, rather than glycine, and lends support to an alternative hypothesis regarding the evolutionary history of AGR-codon assignment in extant chordates rather than that previously proposed.

Xenoturbella is a deuterostome that eats molluscs

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.

New light on the enigmatic Xenoturbella (phylum uncertain): ontogeny and phylogeny

  • O. Israelsson
  • Biology
    Proceedings of the Royal Society of London. Series B: Biological Sciences
  • 1999
The previously unknown embryology of Xenoturbella is reported here that unequivocally corroborates a bivalve relationship and thus once and for all dismisses the potential new phylum plesiomorphic phylum.