Research

We are an international group of evolutionary biologists interested in life, the universe, and everything (ok, only a child of the 80ies like this PI would understand). Together, we investigate how populations evolve to adapt to environmental stress. We are especially interested in the genetic and phenotypic responses of populations to life in deteriorating or poor quality environments.

We use the microbe Baker’s yeast (or budding yeast – Saccharomyces cerevisiae) and its wild relatives as a model system, and a combination of experimental evolution and next generation sequencing. We generate populations that range in genetic variation from clonal (i.e. only genetically identical individuals at first) to extremely diverse (i.e. hybrid swarms made from crossing different species). We propagate these populations for hundreds of generations in stressful environments, using experimental evolution. This allows us to watch the evolutionary process unfold in the lab. We use fitness assays and genome sequencing on these lab-evolved strains from different time points of their frozen “fossil record” to parse the contributions of the four population genetic processes – mutation, genetic drift, recombination and selection. This helps us understand what drives the dynamics of adaptation.

Luckily, yeast comes with its own genetic toolkit and great high quality reference genomes, plus it can reproduce asexually and sexually, which makes it a great system to study the different drivers of evolutionary adaptation.

Some current questions that we are working on are:

  • What is the genetic architecture of fitness and adaptation under environmental stress?
  • How do adaptive dynamics from standing genetic variation differ from adaptation through de novo mutations?
  • How does the rate of environmental change (e.g. gradual vs. abrupt) affect adaptation
  • How likely is mutation-order speciation in sexual versus asexual population?
  • Can hybridization alter the rates and mechanisms of adaptation when populations are facing environmental stress?
  • What is the evolutionary significance of structural genomic variation (e.g. aneuploidy), and how does it affect hybrid fitness?
  • We’ve also recently branched out to work with insects! In collaboration with David Berger at Uppsala University, we are looking at temperature adaptation and the evolution of phenotypic plasticity in seed beetles (Callosobruchus maculatus).

We are always looking for interested Master’s students, who want to join the lab. See examples for available MSc projects here, but we are happy to discuss your own interesting project ideas, too!

If you are interested in any of the above or related questions, please contact rike.stelkens@zoologi.su.se.