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Projekt
Phylogenomics of worm-like lophotrochozoans and platyzoans (Nemertea, Gastrotricha, Gnathostomulida)
Antragsteller
Professor Dr. Torsten H. Struck
Fachliche Zuordnung
Evolution, Anthropologie
Förderung
Förderung von 2007 bis 2015
Projektkennung
Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 50315883
Lophotrochozoa, one of the three major bilaterian taxa proposed based on molecular data, comprises several worm-like taxa. The relationship of these taxa to each other is still unresolved. However, recent results show some progress, though without substantial support yet except for the placement of Sipuncula and Echiura within Annelida. Annelida, Nemertea and Phoronida seems to be closely related to each other, Mollusca and Brachiopoda. Platyzoa, on the other hand, are placed as the sister group to Lophotrochozoa. Furthermore, the inclusiveness of Platyzoa is still controversial, among other reasons, due to the fact that all taxa exhibit long branches. Thus, though there seem to be two major worm-like clades new and more data are wanted to test and eventually corroborate these results. Therefore, to address and test the different hypotheses concerning Nemertea and Platyzoa EST databases using 454 technologies shall be generated for a nemertean, a gnathotomulid and two gastrotrichs. The latter ones shall be complemented by complete mitochondrial genomes. Different strategies shall be explored to obtain ortholog sequences from EST databases for phylogenetic analyses. Furthermore, the long branch problem of the platyzoan taxa shall be thoroughly investigated using novel methods such as node-by-node congruence approaches like PABA or NDI in combination with Wilcoxon signed rank tests, new long branch scores, principal component analyses, heat maps, cluster algorithms and temporal hidden Markov models. These analyses shall reveal the impact of different properties of the genes, e.g. compositional biases, on the phylogenetic reconstruction as well as if Platyzoa is a monophyletic group comprising long branched taxa.
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