Phylogenomic and genomic analyses of the metamonad Pseudotrichomonas keilini, a free-living anaerobic relative of Trichomonas

  • Hend Abu Elmakarem Abdelrahman

Student thesis: Master's ThesisMaster of Science (MSc)


The origin and evolution of eukaryotes has been linked to the rise of oxygen following the Great Oxidation Event, but anaerobic habitats are common today, have existed throughout the Earth’s history, and are rich with eukaryotic life. The Parabasalia are an ancient anaerobic lineage, and the most speciose lineage of Metamonada, a major lineage of eukaryotes. The most well-studied Metamonads are parasites including Trichomonas vaginalis and Tritrichomonas foetus, and Giardia intestinalis but very little genome data is available for free-living members of the group. Here, we sequenced the genome and transcriptome of Pseudotrichomonas keilini; a free-living metamonad.

Comparative genomic analysis indicates that P. keilini possesses a metabolism and gene complement that are in many respects similar to its parasitic relative T. vaginalis. These similarities include a hydrogenosome (anaerobic mitochondrial homologue) that we predict to function much as in T. vaginalis. They also include a complete glycolytic pathway that is likely to represent one of the primary means by which P. keilini obtains ATP.
Phylogenomic analysis indicates that P. keilini branches within a clade of parasitic parabasalids, consistent with the hypothesis that different parabasalid lineages evolved towards parasitic or free-living lifestyles from an endobiotic, anaerobic or microaerophilic common ancestor.
Date of Award29 Sep 2020
Original languageEnglish
Awarding Institution
  • The University of Bristol
SupervisorTom Williams (Supervisor) & Celine Petitjean (Supervisor)

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