Research

We are an international group of evolutionary biologists interested in life, the universe, and everything (whoops, this happens every time). 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. For this, 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”, which allows us to parse the contributions of the four population genetic processes – mutation, genetic drift, recombination and selection – to 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?
  • How does phenotypic plasticity evolve?
  • Can hybridization alter the rates and mechanisms of adaptation when populations are facing environmental stress?
  • What is the evolutionary significance of aneuploidy, and how does it affect hybrid fitness?

1 March 2020 NEWS: We have a PhD position available! Find the full advertisement on the Stockholm University job portal here (all applications must go through this platform). Possible topics include 1) the dynamics of adaptation to changing environments with and without hybridization, 2) the construction of empiricial fitness landscapes using DNA barcodes to track the evolution of lineages over time, 3) understanding the genetic architecture of (hybrid) fitness using machine learning and statistical modelling.

We are also 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.