HILU, KHIDIR W.1*, THOMAS BORSCH2, and KAI MULLER2. 1Department of Biology, Virginia Tech, Blacksburg, VA 24060; 2Botanic Institute and Botanic Garden, University of Bonn, Bonn, Germany. - Contributions of fast evolving genomic regions to deep-level phylogenetics: A case study in basal angiosperms.
Recent information from gene sequences has considerably enhanced our
understanding of flowering plant phylogeny. Individual or combined
data sets from a number of plastid, nuclear and mitochondrial genes
have been used in deep level phylogenetic reconstruction of
angiosperms. Emphasis, however, has been placed on using slow evolving
genes with the notion that levels of homoplasy will be kept at a
minimum. We have been exploring the potential contribution of the
plastid matK gene and the non-coding parts of the trnT-F-region, both
evolving at higher rates than other genomic regions used in deep-level
angiosperm phylogenetic reconstruction. These two regions provide
robust phylogenies for basal angiosperms that are congruent with each
other and with recent angiosperm phylogenies based on combined data of
gene sequences from the plastid and nuclear or from all three genomes.
Analysis of the combined matK and trnT-F data sets
resulted in a single most parsimonious tree. Statistical support for
the majority of nodes substantially increased compared to previous
analyses. Patterns of phylogenetic signal were analysed statistically
and compared to other chloroplast regions in order to identify causes
for the impressive performance of fast evolving genomic regions like
matK and trnT-F.
Key words: basal angiosperms, fast evolving DNA, matK, molecular evolution, trnT-F