Pan-genomic consequences of mating system evolution in Arabis alpina
This project will be supervised by Andrea Fulgione at the Max Planck Institute for Plant Breeding Research.
The evolution of mating systems and reproductive strategies is a fascinating topic in evolutionary biology. While self-fertilization and outcrossing have been studied in exquisite detail, the evolutionary dynamics behind variable and mixed mating strategies are still controversial. Further, mating system has been hypothesized to be a major factor regulating the evolution of transposable elements, structural variants and genome size. In this project we will address these questions using the perennial plant Arabis alpina, which shows stunning variation in mating system across the range. We have collected plants from predominantly self-fertilizing populations, from mixed mating populations and from obligately outcrossing populations. We have sequenced the genomes of 33 representative plants, 11 from each mating system, with long reads and with short reads. In Brassicaceae like A. alpina, the mating system is predominantly shaped by the self-incompatibility (S-) locus, and other modifier loci. The S-locus evolves under negative frequency dependent selection in outcrossers, and this selective pressure is released after a transition to selfing. In this project we will use genome assembly and pangenome graph methods to address the following questions: 1) What are the pan-genomic consequences of mating system variation; 2) How does mating system affect transposable elements, structural variants, and genome size evolution; 3) How does the genomic signature of negative frequency dependent selection at the self-incompatibility locus change in outcrossing compared to selfing populations. This project will shed light on the population genomic and pan-genomic consequences of mating system evolution using the perennial plant A. alpina as a model.
Key publication: Hübner, S. (2022). Are we there yet? Driving the road to evolutionary graph-pangenomics. Current Opinion in Plant Biology, 66, 102195. https://doi.org/10.1016/j.pbi.2022.102195
Link to the Fulgione group homepage: https://www.mpipz.mpg.de/fulgione