Causes and consequences of recombination rate evolution within a songbird species complex

Meiotic recombination is a fundamental evolutionary process that shapes patterns of genetic diversity within and between species. By reshuffling genetic variation, recombination can create novel combinations of alleles, thereby facilitating adaptation and contributing to evolutionary novelty. However, the same process may also break apart existing adaptive combinations, potentially leading to selection for the suppression of recombination. This may be particularly relevant in the context of speciation, especially when lineages diverge in the face of ongoing gene flow. Evolutionary changes in recombination rate along the genome between diverging species may contribute to the maintenance of species boundaries. Beyond playing a direct role in the processes of adaptation and speciation, recombination rate variation along the genome is also critically important for the interpretation of signatures of natural selection.

We aim to quantify genome-wide variation in recombination rate from population level genome sequencing data within five lineages of closely related songbirds of the Oenanthe hispanica (western black-eared wheatear) species complex. Both broadscale (averaged over larger genomic windows) and finescale (localized recombination hotspots spanning a few hundred basepairs) recombination rate variation will be compared among species, as these may be expected to evolve along different timescales. Making use of existing data, we will investigate whether any changes in recombination rate between species may be driven by structural variants. Additionally, we will examine the impact of recombination rate evolution on varying patterns of genetic diversity and signatures of selection among species.

This will be a desk-based project, using existing genome sequencing data from approximately 380 samples. The student will begin by estimating genome-wide recombination landscapes in the five lineages using well-established methods. This project will provide experience working with a wide range of population genomic analyses, in close collaboration with a postdoctoral researcher. We expect the project to result in a scientific publication detailing the variation in recombination rate among the species complex, and its predicted causes and consequences. Additionally, the recombination data generated here will likely contribute to further publications.

We are seeking a student with an interest in population and speciation genomics and a background in bioinformatics. Command line experience is required. Much of the analysis will involve shell scripting and working on a high-performance computing cluster (HPC), so experience with this is desirable.

The student will be part of the Migration research unit at the Swiss Ornithological Institute and will be supervised by Dr. Madeline Chase (Postdoc).