Reconstruction of the phylogeny of anaerobic chytridiomycetes (Neocallimasticales, Fungi) based on multigene-genealogie

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Anaerobic gut fungi are evolutionarily extraordinary in the fungal kingdom. Unique traits of gut fungi especially their anaerobiosis, possession of hydrogenosomes instead of mitochondria, multiple flagella and extremely low genomic GC content caused considerable difficulties with their classification within the class of the chytridiomycetes. Modern systematics of anaerobic fungi based on DNA analyses eliminates the problems with extensive morphological variation of gut fungi depending on environmental conditions. However molecular data based on ribosomal DNA sequences did not answered to satisfaction the relationship between aerobic and anaerobic chytrids because of the repetitive and heterogenous nature of the ribosomal DNA cluster. Molecular analyses of multiple protein-coding genes overcome these problems and offer a robust strategy to study the phylogenetic position of anaerobic fungi among other fungal groups. Single copy protein-coding genes encoding actin, ß- tubulin, translation elongation factor 1-ot or genes encoding enzymes involved in chitin degradation and energy metabolism undergo strong selection and are reliable markers for the reconstruction of phytogenies. The present research proposal results in the generation of a five-gene-genealogy from all taxonomic groups of the chytridiomycetes in comparison with major clades of other fungal lineages. Since animals and fungi are known to be sister groups and flagellate fungi are accepted to represent the most basal lineage of fungi our project will shed light on the ancient evolutionary history of divergence between animals and fungi.