more projects

Here you can find other projects I am working on/ I have been involved into.

2018, Population dynamics of the Sierra Nevada yellow-legged frog (Rana sierrae) in Dusy Basin, Kings Canyon National Park

Coming soon.

2017-18, Metagenome-assembled genomes from two thermal pools in the Uzon Caldera, Kamchatka, Russia

Coming soon

See our preprint here:

2015-17, Sex differentiation and its implications for conservation in grayling

Coming soon

Having a hard time with the reviewers!

2015, Maternal allocation of egg carotenoids in brown trout

Coming soon

Supervision and Mentoring

This paragraph is a niche for students I supervised or mentored. I asked them to write about their projects in guest posts. Let’s start with David Zeugin in Claus Wedekind’s lab. We studied grayling embryos and how they respond to pathogens and gynogenesis in the context of inbreeding. He explains it here.

2010-14, my PhD thesis: Diversity of bacterial symbionts on salmonid eggs: genetic and environmental effects

Because I was very interested in the immune system, mate choice and conservation genetics, I applied for a fellowship to do a PhD in the Ecology & Evolution Department at the University of Lausanne, Switzerland with Claus Wedekind (T-shirt study) and Luca Fumagalli (conservation geneticist) on the MHC and its implications in salmonid fishes. I received the fellowship. Here is my first paper/chapter of my PhD thesis on embryonic MHC gene expression in whitefish, Coregonus spp. In this project we investigated whether the MHC is already relevant for embryos when they mount their first immune response against a pathogen. We measured gene expression, and we quantified the heritability of this trait using a powerful experimental design and a quantitative genetics approach. This chapter was published in the journal Molecular Ecology. During this first project I became very interested in using salmonid embryos as a system to study host-microbiome interactions. How I got fascinated by fish embryos is described in a blog post here.

During the second winter as a PhD student, I collected naturally-spawned fish eggs of wild populations in different lakes and rivers in Switzerland. Then I applied environmental sequencing to characterize the bacteria living on them. Next, I quantified the effects of geographic distance, host species diversity, and water temperature on bacterial community composition in the wild. The results were published in the journal of Aquatic Sciences and Scientific Reports. They are explained in more detail in this blog post. This first part of my PhD included many field trips to find eggs; for example diving in Lake Thun, canoeing in the capital of Switzerland, more diving in Lake Thun with my invaluable student and friend Grégory Brazzola, training my eyes to see eggs in the wild, developing tools to collect eggs buried brown trout eggs in river beds, as well as grayling eggs. During my last trip for this project, I had the opportunity to bring my family from Houston, Texas to my home canton Graubünden, and I started my long-term collaboration with Marcel Michel, Reto Gritti and Roland Tomaschett from the department of fish and wildlife (Amt für Jagd und Fischerei, Graubünden).

What ultimately had to follow these field studies were controlled experimental set-ups to study the interaction of salmonid embryos and their associated bacterial communities in more detail.

Accordingly, we brought gametes from wild fish into our lab and fertilized them in vitro to have embryos. The eggs of many females were fertilized with sperm from many males to quantify maternal and paternal effects on embryo traits. These embryos were then used to run experiments. In the first experiment we manipulated the microbiome growing on the eggs with nutrients to study the effects of host genetics and available resources on egg-associated bacterial community composition. This study was published in the journal Molecular EcologyIn another experiment with a similar design, we measured whole genome expression responses in the embryos to infection with an opportunistic fish pathogen, Pseudomonas fluorescens. This study can be found in the journal of Fish & Shellfish Immunology 

2009-10, my Master thesis: Female mating preferences and probabilistic paternity analysis in the MHC of humpback whales, Megaptera novaeangliae

For my Master thesis I joined Per Palsbøll and Martine Bérubé at Stockholm University, Sweden to learn more about evolutionary genetics of marine mammals. My project was a genetic investigation of female mating preferences in humpback whales. We sampled mother-calf pairs in the Gulf of Maine, USA, during their feeding season; as well as males in the West Indies, Caribbean, during their breeding season. I amplified, cloned and sequenced a locus in their major histocompatibility complex (MHC) and inferred the nucleotide similarity between mothers and their calves. Then I used the alleles in the males and simulated many humbpack whale generations by mating these alleles with the mothers’ alleles and creating simulated calves. I used these simulated calves to compare the observed to the simulated similarity of mother calf pairs at the MHC. The simulations assumed no female mate choice. Deviations from these values could be interpreted as female mate choice for males with particularly similar or dissimilar alleles at this locus. Interestingly, the real calves were more similar to their mothers at the MHC than expected. These results were never published but I attached my Master thesis.

Martine trained me very thoroughly in their molecular genetic lab and Per took a lot of time to explain and discuss population genetics. Per arranged a fieldwork trip for me to help his friends and collaborators Jooke Robbins and David Mattila at the Provincetown Center for Coastal Studies in Massachusetts. Here are some photographs I took during this trip: first encounter with the whales; getting used to living on a boat (in German); becoming experienced.

My Master project is also explained in a blog post here (English) and here (German).

2007, Sweden: Saving the Endangered Fennoscandinavian Arctic Fox, Alopex lagopus

As and undergraduate student I worked as a volunteer for Prof. Anders Angerbjörn at Stockholm University, Sweden. He dedicated his life and research to studying and protecting the endangered Arctic Fox in the Swedish mountain Tundra. My contribution included a several weeks long hiking and camping trip during which we searched for wild foxes, caught them, marked them and took blood and feces samples for genetic parentage analyses. I learned a lot about wildlife biology and the logistics of large-scale field experiments.

Link to one of my first blog posts — about this project. Not much text at that time but many photos and impressions.