Jan Andersson lab

The majority of the eukaryotic diversity is microbial. We are using comparative genomics methods to study these organisms. We are especially interested in evolutionary processes affecting the genomes of diplomonads (e.g. Giardia and Spironucleus) ads and how these relate to the phenotypic diversity in this fascinating group of organisms.

Popular science presentation

The overall goal of our research is to understand how different evolutionary processes acting on the genomic level have changed, and still are changing, the biology of microbial eukaryotes. We focus on diplomonads, a peculiar group with the genetic material divided into two separate nuclei in the cell. Knowledge from our research gives a deeper understanding of the origin and evolution of parasites, and the role of eukaryotic microbes in natural environments.

I am using a diplomonads, a group of microorganisms as a model since many years. We are using sequencing technology to do whole genome sequencing of different diplomonads. Using bioinformatic tools we are determine differences and similarities within the group, as well as between diplomonads and other organisms. Then we are trying to couple differences in the genome to variations in the biology.

The group diplomonads both contains parasites which, for example, infect humans (e.g. Giardia lamblia) and fish (e.g. Spironucleus salmonicida), but also species that do not cause disease in the host, and free-living species. We have shown that diplomonads have adapted to oxygen-poor environments by acquisition of genetic material from other organisms. We have also demonstrated the presence of hydrogenosomes, hydrogen-producing organelles, in some diplomonads. Our studies of the genome sequences also show that a rapid evolution of gene families also contributes to specializations within the group. There are strong indications that diplomonads undergo genetic exchange via rare sexual recombination. Thanks to our research diplomonads are now one of the more well-studied groups of eukaryotic microbes.

Research projects

Diplomonads is a group of eukaryotes that strives in oxygen-poor environments that have gained attention because of their pathogenicity, basic cell structure and evolutionary peculiarities. For example, most diplomonads have two transcriptionally active nuclei and no sexual cycle have been observed although there are various signs of recombination. Most research has previously been focused on a single species, Giardia intestinalis, which is an important human intestinal pathogen.

We are currently targeting several diplomonad species found in different niches (free-living, commensals and pathogens). This research is performed in a larger group which is using a wide array of methods, ranging from experimental fish infections to advanced phylogenetic methods. The aim is to gain insight into different aspects of the cell biology, pathogenicity and evolution of various diplomonads.

Within our group we mainly focus on evolutionary aspects of diplomonad biology. We use bioinformatic tools, such as assembly, annotation and phylogenetics, to address evolutionary questions such as:

  • adaptation of diplomonad lineages to increasing oxygen-levels during the evolution to pathogenic lifestyles
  • secondarily adaptation to a free-living lifestyle by diplomonads such as Trepomonas and Hexamita
  • genome structure evolution and the relationship to sexual or parasexual life cycles

Group members

Research leader: Jan Andersson

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