Format: ORAL

Meng Lu1,2, Peter M. Hollingsworth2, and Alex D. Twyford1,2

1 Ashworth Laboratories, Institute of Ecology and Evolution, The University of Edinburgh, Edinburgh, EH9 3FL, UK 2 Royal Botanic Garden Edinburgh, 20A Inverleith Row, Edinburgh, EH3 5LR, UK

Hybridization can have various evolutionary outcomes, from homogenizing the differences between populations to generating phenotypic and genotypic novelty. However, the majority of these important phenomena are evaluated in isolated case studies of evolutionary model species chosen for their notable hybridization outcomes, and how well the current findings represent generalities of natural hybridization in a wider range of taxa remains unknown. As such, this project aims to explore the general patterns of natural hybridization in the British flora using genomic approaches. The British flora is very well-studied with extensive records of hybrids, rendering it the ideal system for understanding natural hybridization at a broad scale. Specifically, we evaluate the extent of introgression in native flowering plants, using model-based demographic inference on whole genome resequencing data. Six conspicuous hybridizing species pairs were selected, each pair from a distinct taxonomic family, including genera that are well known for their common natural hybrids, such as Primula and Geum. The results support models with asymmetrical gene flow in focal pairs. Additionally, using a demographically explicit genome scan approach, we were able to estimate heterogeneous gene flow across the studied genomes and identify candidate barrier regions to gene flow. By studying hybridization outcomes of species pairs from diverse taxonomic lineages, we hope to provide a comparative perspective to understand how introgression is affected by intrinsic factors, such as parental species divergence.