Meeting Abstract

1.3  Jan. 4  Nuclear Genes and Phylogeny of Lophotrochozoa STRUCK, Torsten H; University of Osnabrueck, Osnabrueck, Germany struck@biologie.uni-osnabrueck.de

Well-corroborated hypotheses explaining the relationships within Lophotrochozoa are still lacking and thus their phylogeny can be regarded as unresolved. Lophotrochozoa comprises at least Mollusca, Annelida, Brachiopoda, Phoronida and Bryozoa and the taxon name refers to the possession of either a lophophorate or trochophore feeding apparatus. Several other taxa like Sipuncula, Nemertea, Kamptozoa, Rotatoria and Platyhelminthes are also discussed to belong to the taxon. For example, due to molecular phylogenetic analyses based on the nuclear small and large ribosomal genes the inclusion of Sipuncula within Annelida as well as of Phoronida within Brachiopoda appears to be likely, but is not significantly supported. Herein I assess the utility of nuclear protein coding genes like Aldolase, Myosin II Heavy Chain or Methionine Adenosyltransferase, which have been used to address metazoan phylogeny, but not lophotrochozoan relationships. In contrast to ribosomal genes, protein-coding genes are usually unambiguously to align and thus position homology is given with higher certainty. Besides the nucleic acid sequences amino acid sequences can be exploited for phylogenetic reconstructions. Together with the ribosomal genes larger combined data sets can be established to overcome the bad signal to noise ratio in single or few gene phylogenetic reconstructions of Lophotrochozoa.