The Oxymonad Genome Displays Canonical Eukaryotic Complexity in the Absence of a Mitochondrion

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskrift


The discovery that the protist Monocercomonoides exilis completely lacks mitochondria demonstrates that these organelles are not absolutely essential to eukaryotic cells. However, the degree to which the metabolism and cellular systems of this organism have adapted to the loss of mitochondria is unknown. Here, we report an extensive analysis of the M. exilis genome to address this question. Unexpectedly, we find that M. exilis genome structure and content is similar in complexity to other eukaryotes and less "reduced" than genomes of some other protists from the Metamonada group to which it belongs. Furthermore, the predicted cytoskeletal systems, the organization of endomembrane systems, and biosynthetic pathways also display canonical eukaryotic complexity. The only apparent preadaptation that permitted the loss of mitochondria was the acquisition of the SUF system for Fe-S cluster assembly and the loss of glycine cleavage system. Changes in other systems, including in amino acid metabolism and oxidative stress response, were coincident with the loss of mitochondria but are likely adaptations to the microaerophilic and endobiotic niche rather than the mitochondrial loss per se. Apart from the lack of mitochondria and peroxisomes, we show that M. exilis is a fully elaborated eukaryotic cell that is a promising model system in which eukaryotic cell biology can be investigated in the absence of mitochondria.


  • Anna Karnkowska
  • Sebastian C. Treitli
  • Ondřej Brzoň
  • Lukáš Novák
  • Vojtěch Vacek
  • Petr Soukal
  • Lael D. Barlow
  • Emily K. Herman
  • Shweta V. Pipaliya
  • Tomáš Pánek
  • David Žihala
  • Romana Petrželková
  • Anzhelika Butenko
  • Laura Eme
  • Courtney W. Stairs
  • Andrew J. Roger
  • Marek Eliáš
  • Joel B. Dacks
  • Vladimír Hampl
  • Fabia Ursula Battistuzzi (redaktör)
Externa organisationer
  • Charles University in Prague
  • University of Warsaw
  • University of Alberta
  • University of Ostrava
  • Uppsala universitet
  • Dalhousie University


Sidor (från-till)2292-2312
TidskriftMolecular biology and evolution
Utgåva nummer10
StatusPublished - 2019 okt 1
Peer review utfördJa
Externt publiceradJa