EST sequencing of Onychophora and phylogenomic analysis of Metazoa

Onychophora (velvet worms) represent a small animal taxon considered to be related to Euarthropoda. We have obtained 1873 5′ cDNA sequences (expressed sequence tags, ESTs) from the velvet worm Epiperipatus sp., which were assembled into 833 contigs. BLAST similarity searches revealed that 51.9% of t...

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Bibliographic Details
Published in:Molecular phylogenetics and evolution 2007-12, Vol.45 (3), p.942-951
Main Authors: Roeding, Falko, Hagner-Holler, Silke, Ruhberg, Hilke, Ebersberger, Ingo, von Haeseler, Arndt, Kube, Michael, Reinhardt, Richard, Burmester, Thorsten
Format: Article
Language:English
Subjects:
Animals
Arthropoda
Articulata
Base Sequence
Chordata
Ecdysozoa
Epiperipatus
EST
Euarthropoda
Eukaryotic Cells - metabolism
Expressed Sequence Tags
Genome - genetics
Metazoa
Nematoda
Onychophora
Phylogeny
Ribosomal Proteins - genetics
Sequence Alignment
Tardigrada
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Summary:Onychophora (velvet worms) represent a small animal taxon considered to be related to Euarthropoda. We have obtained 1873 5′ cDNA sequences (expressed sequence tags, ESTs) from the velvet worm Epiperipatus sp., which were assembled into 833 contigs. BLAST similarity searches revealed that 51.9% of the contigs had matches in the protein databases with expectation values lower than 10 −4. Most ESTs had the best hit with proteins from either Chordata or Arthropoda (∼40% respectively). The ESTs included sequences of 27 ribosomal proteins. The orthologous sequences from 28 other species of a broad range of phyla were obtained from the databases, including other EST projects. A concatenated amino acid alignment comprising 5021 positions was constructed, which covers 4259 positions when problematic regions were removed. Bayesian and maximum likelihood methods place Epiperipatus within the monophyletic Ecdysozoa (Onychophora, Arthropoda, Tardigrada and Nematoda), but its exact relation to the Euarthropoda remained unresolved. The “Articulata” concept was not supported. Tardigrada and Nematoda formed a well-supported monophylum, suggesting that Tardigrada are actually Cycloneuralia. In agreement with previous studies, we have demonstrated that random sequencing of cDNAs results in sequence information suitable for phylogenomic approaches to resolve metazoan relationships.
ISSN:1055-7903
1095-9513
DOI:10.1016/j.ympev.2007.09.002