Evolution of hydrogenosomes and horizontal gene transfer
Voncken, F., Akhmanova, A., Boxma, B., Hackstein, J.
University of Nijmegen, Dept. Microbiology and Evolutionary Biology,
Toernooiveld 1, NL-6525 ED, Nijmegen, The Netherlands.
Hydrogenosomes are membrane-bound organelles found in a wide variety of anaerobic, amitochondriate eukaryotes, e.g. trichomonads, Vahlkamphidae, ciliates, and chytrids. They are characterized by the presence of an unique metabolic pathway leading from pyruvate or malate to acetate and hydrogen. The evolutionary origin is elusive since alle hydrogenosomes studied so far do not contain an organellar genome that can disclose its ancestry. Moreover, the occurence of hydrogenosomes in taxa that are only distantly related suggests that hydrogenosomes evolved several times - and not necessarily from a common ancestor.
Until now, only the hydrogenosomes of trichomonads have been studied in more detail. Phylogenetic analysis of the derived amino acid sequences of several hydrogenosomal proteins of the anaerobic mastigote Trichomonas vaginalis fails to provide unequivocal evidence for a common ancestry. It became evident that certain hydrogenosomal proteins have a mitochondrial descent, whereas others are likely to be acquired by horizontal gene transfer.
Hydrogenosomes of trichomonads, anaerobic chytrids and ciliates are structurally and biochemically different. We will present evidence that retargeting and horizontal gene transfer played an important role in the evolution of the hydrogenosomes.
| LOCATION |
DATE |
TIME |
| Lecture Hall I |
Monday, April 6 |
09:55 am |