As compared to other ancient and basal Ecdysozoan phyla such as the Nematomorpha (~ 350 known species), the Priapulida (~16 species) and the Kinorhyncha (~180 species), the phylum Nematoda stands out for being speciose (~ 27,000 described species), highly abundant, and widespread in nearly all terrestrial, freshwater and marine habitats. We will present results of phylogenetic analyses of approximately 10% of the described nematode biodiversity (~ 2,800 taxa; with underrepresentation of marine and tropical terrestrial species). We have tried multiple genes for phylogenetic reconstruction but so far the small subunit of the ribosomal DNA (~ 1,700 bp) is the only gene that could easily be amplified and aligned for a wide range of nematode species. The resulting alignment including secondary structure information was analysed on the CIPRES Science Gateway (San Diego, USA), using RAxML, a maximum likelihood-based inference for large phylogenetic trees, and Bayesian inference, and the outcome of both analyses will be presented. Some relevant features of the resulting phylogenetic trees will be discussed, and attention will be paid as to whether or not such a single gene tree does provide us with useful information about organismal relationships. This talk will also be used to describe the positioning and the relationships between the nematode taxa that will be discussed in more detail in Theme 2: Morphology, taxonomy, phylogeny and classification.
|Title of host publication||Proceedings of the 6th International Congress of Nematology|
|Publication status||Published - 2014|
|Event||6th International Congress of Nematology, Cape Town, South Africa - |
Duration: 4 May 2014 → 9 May 2014
|Conference||6th International Congress of Nematology, Cape Town, South Africa|
|Period||4/05/14 → 9/05/14|
Helder, J., Mooijman, P. J. W., van den Elsen, S. J. J., van Megen, H. H. B., Vervoort, M. T. W., Quist, C. W., Bert, W., Karegar, A., Karssen, G., & Decreamer, W. (2014). Biological and systematic implications of phylogenetic analysis of ~ 2,800 full length small subunit ribosomal DNA sequences. In Proceedings of the 6th International Congress of Nematology (pp. 26-26)