Establishing a long-term experimental evolution experiment of an archaeal host-symbiont system

Since the description of the Archaea as a separate domain of life about forty years ago, much has been learned about the evolution, biology and ecological significance of members of this lineage. Yet, the extent to which archaea are investigated and the knowledge that this research has generated still lags far behind our scientific insights into all aspects of bacterial biology.

During the past decade, cultivation-independent approaches such as metagenomics, which allows to sequence DNA directly from environmental samples and to subsequently reconstruct individual genomes of organisms in these samples, has brought about significant new insights into the evolution and genomic potential of uncultivated microorganisms. In particular, the recent years have witnessed the discovery of various and previously unknown archaeal lineages of high taxonomic rank such as the enigmatic DPANN archaea. DPANN archaea include several different and highly diverse phyla that are comprised by organisms with small cell sizes and genomes and encode a limited metabolic repertoire suggesting that they may be dependent on symbiotic interactions with other organisms. For instance, this radiation also includes the only known parasitic archaeaon – Nanoarchaeum equitans – which grows as an ectosymbiont of the crenarchaeote Ignicoccus hospitalis.

In order to better understand the role of DPANN archaea in the evolution and diversification of the Archaea, the selected student will set up experimental evolution experiments of the cultivated system of N. equitans and I. hospitalis. While N. equitans can only be grown in co-culture with its anaerobic and hyperthermophilic host, I. hospitalis has better growth on its own. In this project, you will establish and maintain co-cultures of both organisms as well as pure cultures of I. hospitalis and follow those over various generations by among others using microscopy and genome sequencing techniques. This will allow us to determine rates of genome evolution and horizontal gene transfer as well as unveil potential adaptations towards a symbiotic lifestyle and thereby shed first insights into how a DPANN archaeon influences the evolution of its hosts.

Requirements

We are looking for a highly motivated MSc student willing to learn and apply cross-disciplinary approaches and with basic training in evolutionary and molecular biology, as well as microbiology and the cultivation of microorganisms. Due to the international character of our research, good command of English, spoken as well as written, is a major advantage.

Contact

If you are interested in this master project, please contact Dr. Anja Spang (anja.spang@nioz.nl).