Selection maintains genetic coupling of functional trait trade-offs despite gene flow in an oak hybrid zone
Year: 2026
Type: preprint
Abstract: Resource allocation trade-offs during seedling establishment can generate coordinated interspecific variation in functional traits that reflects contrasting growth–survival strategies. Yet whether and how natural selection maintains these trade-offs and their multilocus genetic architecture remain poorly understood. Using a natural hybrid zone between two East Asian oaks, we evaluated whether loci associated with these trade-offs showed signatures of selection and genetic coupling despite ongoing hybridisation. Acorns collected across the zone were cultivated in a common garden, where we quantified 26 seedling growth and functional traits, and analysed whole-genome variation. We identified coordinated trade-offs within leaf function and plant architecture. Trait-associated genomic regions demonstrated excess inter-chromosomal linkage disequilibrium in the hybrids, consistent with genetic coupling, and exhibited elevated interspecific differentiation and steeper local genomic clines than background loci. Together, these results suggest that selection contributes to maintaining resource-allocation trade-offs and genetic coupling among their underlying loci despite ongoing gene flow.
Institution: Kyoto University
Language: English
Subfield: Genetics
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W7161643303