Wetenschap - 14 februari 2019

How did complex life come about? - Thijs Ettema is the new professor of Microbiology

tekst:
Albert Sikkema

The Wageningen alumnus Thijs Ettema (41) has succeeded Willem de Vos as professor of Microbiology. He established ground-breaking fundamental research in Sweden on the evolution of complex life forms. He wants to build on that at WUR.

The new professor of Microbiology Thijs Ettema studies how plants, fungi and animals have evolved out of archaea. ©Guy Ackermans

Ettema got his PhD in 2005, under the supervision of Willem de Vos and John van der Oost. A few years later, he left for a postdoc position at the University of Uppsala, where he did well on tenure track and established his own research group with a European grant of 1.5 million euros. The central research question was: how have plants, fungi and animals emerged in the course of evolution from bacteria and archaea (prehistoric bacteria)? In recent years, Ettema has published several ground-breaking articles on this subject in Nature.

Evolution

‘I was already working on archaea during my Wageningen PhD research,’ says Ettema. Little was known about these single-cell organisms at the time. Ettema was one of the first people to use bio-informatics and genome analyses to figure out their biology. ‘The function of most genes was still not understood. We started comparing the genomes of archaea in order to predict the functions of different genes.’

In Sweden, Ettema focused on more fundamental questions. About 3.5 billion years ago, a division arose between bacteria and archaea, both cells without a cell nucleus, known as prokaryotes. Later in evolution, eukaryotes were formed: cells with a cell nucleus, and other organelles such as mitochondria. But a big question in biology remains: how did those eukaryotes come about?

Geysers
Ettema’s Swedish group collected samples of micro-organisms in geysers and underwater volcanoes, because archaea often live in extreme conditions. Then they cut all the DNA into pieces, determined the DNA sequence of those pieces and tried to reconstruct the genome of the micro-organisms. Why make it so complicated? Why not determine the genome of all the micro-organisms directly? ‘Because we need a uniform pure culture in order to determine DNA. You have to culture that in the lab, but 99 per cent of these micro-organisms do not grow in the lab.’

Expertise
Ettema expects that he’ll have more chance of success in Wageningen than in Uppsala. ‘Since the Microbiology chair group was established in 1917, Wageningen has gained a lot of experience in getting micro-organisms to grow, especially under anaerobic conditions. What is more, there is a high level of expertise here, and the infrastructure for research is fantastic. This kind of job doesn’t come up very often.’ He will bring six researchers from his Swedish group with him to Wageningen. 


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