Research

We are an international group of evolutionary biologists interested in life, the universe, and everything (ok, only a child of the 80s 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 and the role of hybridization in evolution.

We use the microbe Baker’s yeast (aka Brewer’s or budding yeast – Saccharomyces cerevisiae) and its wild relatives, and a combination of experimental evolution and genome sequencing to understand what drives the dynamics of adaptation. We generate populations that range in genetic variation from clonal (i.e. genetically identical individuals) to extremely diverse (i.e. hybrid swarms made from crossing different species) and propagate these populations for hundreds of generations in stressful environments. This allows us to watch evolution in action and freezing populations at different time points gives us a yeasty “fossil record”. We use this to parse the contributions of the four population genetic processes – mutation, genetic drift, recombination and selection – to adaptation.

Thanks to the Awesome Power of Yeast Genetics, and the fact that it reproduces asexually and sexually, yeast is a great system to study the drivers of evolutionary adaptation and the role of hybridization in evolution.

Some of the questions we are currently working on:

  • What is the genetic architecture of fitness and adaptation under environmental stress?
  • How likely is parallel evolution when populations adapt from standing genetic variation?
  • How do the type and rate of environmental change affect adaptation dynamics?
  • How likely is mutation-order speciation when selection is on simple vs. complex traits?
  • What is the evolutionary significance of structural genomic variation (e.g. aneuploidy), and how does it affect hybrid fitness?
  • Is the distribution of fitness effects (DFE) comparable across environments and systems? This is a collaboration with some lovely colleagues in the Math Dept (Chun-Li Biu).
  • We’re also working with insects! Together with David Berger at Uppsala University, we are looking at temperature adaptation and the evolution of phenotypic plasticity in seed beetles (Callosobruchus maculatus).

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

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!