Earth's magnetic field guides migra­tory birds over vast distances. Despite decades of research, the mecha­nisms behind avian magne­tosen­si­tiv­ity remain unclear. Recent studies suggest cryptochromes play a role, but proving this is challeng­ing. Our project explores whether rhodopsins, previ­ously overlooked, also contribute. We aim to under­stand these photore­cep­tors at a molec­u­lar level and enable behav­ioural exper­i­ments with trans­genic birds.

For centuries, sailors have navigated unknown waters using compasses. Similarly, Earth's magnetic field guides various migra­tory bird species over thousands of kilome­tres to their winter­ing grounds. Despite 60 years of research, the light-depen­dent molec­u­lar mecha­nisms under­ly­ing avian magne­tosen­si­tiv­ity remain elusive. Recent studies have shown that the cryptochrome photore­cep­tor in migra­tory songbirds forms radical pairs that can be influ­enced by strong magnetic fields. However, proving the causal­ity between cryptochrome and avian naviga­tion is challeng­ing due to the lack of suitable genet­i­cally modifi­able model organisms. 

In this context, rhodopsin photore­cep­tors have been overlooked as poten­tial magne­tode­tec­tors due to their appar­ent inabil­ity to form radical pairs, a require­ment for magnetic sensi­tiv­ity based on a theory from the 1970s. Never­the­less, recent findings suggest an impli­ca­tion of rhodopsins in the magnetic sense. This project aims at inves­ti­gat­ing whether specific rhodopsins, inter­act with cryptochrome in vitro or facil­i­tate energy trans­fers. Addition­ally, we will explore the photo­chem­istry of rhodopsins. To address these questions, we will purify various rhodopsins via biochem­i­cal methods and subject them to compre­hen­sive spectro­scopic studies. The opsin genes origi­nate from genet­i­cally modifi­able bird species, thereby opening the door to behav­ioural exper­i­ments with trans­genic organisms.