Authors: Kristaps Sokolovskis, Max Lundberg, Susanne Åkesson, Mikkel Willemoes, Tianhao Zhao, Violeta Caballero-Lopez1 & Staffan Bensch
Publication: Nature Communications
Publication Link: https://www.nature.com/articles/s41467-023-35788-7
Abstract: Migratory routes and remote wintering quarters in birds are often species and
even population specific. It has been known for decades that songbirds mainly
migrate solitarily, and that the migration direction is genetically controlled.
Yet, the underlying genetic mechanisms remain unknown. To investigate the
genetic basis of migration direction, we track genotyped willow warblers
Phylloscopus trochilus from a migratory divide in Sweden, where South-West
migrating, and South-East migrating subspecies form a hybrid swarm.We find
evidence that migration direction follows a dominant inheritance pattern with
epistatic interaction between two loci explaining 74% of variation. Consequently,
most hybridsmigrate similarly to one of the parental subspecies, and
therefore do not suffer from the cost of following an inferior, intermediate
route. This has significant implications for understanding the selection processes
that maintain narrow migratory divides.