Determinants of 5mC chromatin modifications in natural populations of the barn swallow

• Applicant: Dr. Sarah Mueller
• Subject Area: Evolution, Anthropology
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 521532636

Our current understanding of evolution is undergoing an expansion as we incorporate non-genetic factors into the traditional framework of evolutionary theory. Analogous to genetic mutations, epigenetic modifications of the DNA backbone might mediate phenotypic changes and be subject to independent evolutionary change. If stably inherited and independent of genetic variation, they harbor the potential to impact population processes on evolutionary timescales. Despite promising examples from plants, the extent and significance to which chromatin modifications contribute to evolutionary processes in natural animal populations remains largely unknown. This project aims to fill this gap by jointly investigating genome-wide patterns of 5-methyl-cytosine (5mC) DNA methylation (RRBS data) and genetic variation (WGS data) in the barn swallow (Hirundo rustica). A global sampling design across all six described subspecies and two key hybrid zones will help untangle the contribution of genetic and environmental factors mediating observed patterns of methylome variation. First, I will apply basic population genetic techniques to decompose the evolutionary signal contained in both methylome and genetic variation and quantify the degree of covariation. On the basis of these results, I will investigate the contribution of environmental and genetic factors that determine patterns of DNA methylation variation in detail. Using two hybrid zones, which combine aspects of traditional genetic backcrossing and a common garden design, I will finally leverage this natural system to explore the contribution of cis- and trans-regulatory elements to DNA methylation variation. The proposed project will provide valuable insight into the parameters shaping methylation patterns in natural populations and consequently assess potential for an autonomous contribution of chromatin modification to evolution.

• DFG Programme: WBP Position