Thank you for finding me! My name is Marius Roesti and I’m a Swiss postdoc in the group of Katie Peichel at the University of Bern in Switzerland.

I'm much fascinated by nature's incredible diversity. My research thus focuses on understanding the evolutionary processes governing biological diversification. Broadly speaking, I like integrating population genomics within a strong ecological and phenotypic framework to shed light on the drivers and constraints of adaptive diversification and speciation. My main empirical study system is the recent adaptive radiation of threespine stickleback fish, although I have been working on other organisms (mostly fish) as well. Please find my published work here.

Current projects involve the study of stickleback populations inhabiting distinct environments, such as lakes differing mainly in their abiotic properties, or lakes differing in a single biotic factor – that is, the presence/absence of a competitor (sculpin fish). I am describing phenotypic adaptive divergence in both stickleback and sculpin as a consequence of their co-existence. High-resolution genome scans illuminate how the genome diverges in stickleback as a consequence of their co-existence with sculpin. My current focus is on allopatric populations, which stands in contrast to most of my previous (genomics) work where the emphasis was on adaptive divergence in the presence of gene flow.

Besides the above comparative projects on wild populations, I am also conducting experiments in (semi-)natural environments to test specific evolutionary predictions. One of the questions I am aiming to answer with a large-scale experiment conducted at UBC's Experimental Fish Pond Facility, and in collaboration with Dolph Schluter, is whether a simple biotic change to the environment of an organism can result in reproductive isolation (speciation) as a by-product.

Finally, the genomics insights from my empirical research stimulate and inform my theoretical work. I am using individual-based forward simulations to better understand the genomic footprints of selection. Gaining a mechanistic and evolutionary understanding for intra-genomic variation in the rate of crossover (recombination) and how such variation influences adaptive genome divergence is a particular interest of mine. Simulations further help me explore how crossover rate variation in context of polygenic adaptation influences evolutionary genomics methodologies and inferences, such as the search for genomic targets of selection.

If you like to get further information on my past or ongoing work, please do not hesitate to contact me.


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