Research

The role of genomic structural variation during adaptation

Genomes can be highly flexible and evolve based on processes that duplicate, remove, or rearrange genetic elements within or among chromosomes. The resulting genomic structural variation can be subject to selection and particular genome architectures might spread because they are favored during adaptation. I am using a combination of comparative genomics and statistics to investigate whether genome architecture has sometimes evolved in a non-random way during adaptation.

Adaptation and speciation in stick insects

Timema stick insects live and feed on various host plants, with several Timema species showing parallel adaptations to different hosts. I use population genomics to study the genetic and environmental processes contributing to local adaptation and that might be important for population differentiation with gene flow. I largely focus on one of the species, T. cristinae, which is not only adapted to different host plants but also exhibits a color polymorphism conferring crypsis on different plant parts of individual hosts (i.e., stems or leaves). I am interested in the evolution and genetic architecture of this polymorphism that is maintained in full sympatry.

Hybrid zone simulations

I use computer simulations to study the genomic outcomes of hybridization and admixture. In particular, I am interested in the efficiency of different genetic architectures of reproductive isolation in maintaining species differences in secondary contact, and their effects on introgression and gene flow. Together with Alex Buerkle, I worked on the simulation software dfuse that can model the genomic outcomes of hybridization with different genetic architectures of fitness.

Poplar hybrid zones

I studied the genetics of reproductive isolation and species differences in replicate hybrid zones of European aspen (Populus tremula) and white poplar (P. alba) during my dissertation. Replicate Populus hybrid zones show highly parallel genomic outcomes of genetic ancestry and introgression, indicating a strong role of genetically based reproductive barriers. By jointly inferring genetic ancestry and paternity in a hierarchical Bayesian model, we found that postzygotic selection acting on seedlings contributes substantially to the maintenance of species barriers in these hybridizing, wind-pollinated forest trees.