Isabelle Ewers

Isabelle Ewers is a researcher in Eukaryotic Microbiology at the Faculty of Biology, University of Duisburg-Essen, Germany. She specializes in phylogenetic placements for taxonomic assignment of environmental DNA, particularly focusing on colpodean ciliates and their evolutionary and ecological characteristics.

Her research compares phylogenetic placement methods (EPA-ng, GAPPA) with pairwise alignment approaches (VSEARCH) to resolve taxonomic assignments in environmental sequencing data. This includes analyzing operational taxonomic units (OTUs) from Neotropical rainforest soils, evaluating likelihood weight ratios for placement accuracy, and measuring expected distances between placement locations to quantify uncertainty.

Key findings include demonstrating that phylogenetic placement outperforms pairwise alignment for low-similarity sequences and establishing frameworks for interpreting multi-placement scenarios in microbial eukaryotes. Her work has implications for improving metabarcoding workflows and understanding protist diversity in understudied ecosystems.