Speciation in songbirds through the molecular lens – SpeCular

Elucidating the mechanisms that give rise to the origin of new species remains a major goal in evolutionary biology. Disruption of genome integrity in hybrid individuals accompanied by the dysregulation of core molecular processes represents one important route to reproductive isolation and speciation. While such hybrid incompatibilities have primarily been studied in laboratory settings, little is known about the mutational mechanisms causing dysregulation and their relevance to reproductive isolation and speciation in natural species, where also divergent ecological selection is suggested to play a role in the speciation process. Moreover, it remains to be established if the same or different types of mutations, e.g. point mutations or structural re-arrangements, are involved in adaptive divergence between species and incompatibilities in their hybrids. We propose to study these fundamental questions in two songbirds that represent a classic case of allopatric speciation with secondary contact that has proceeded to an advanced stage with sterile F1 hybrids. By systematically comparing the contribution of different types of mutations to the dysregulation of relevant molecular processes in natural F1 hybrids, we aim to identify their importance for the emergence of hybrid incompatibilities. By complementing this investigation with a population genomics approach in the parental species, we aim to gain insights into the interplay between divergent ecological selection and the formation of intrinsic incompatibilities in hybrid genomes. Moreover, this project bridges molecular and evolutionary biology, and aims to expand our knowledge about fundamental regulatory mechanisms and regulatory divergence in songbirds.