Migratory birds have long fascinated scientists with their ability to navigate vast distances precisely. A recent study led by biologists Dr. Corinna Langebrake and Prof. Dr. Miriam Liedvogel from the University of Oldenburg and the Institute of Avian Research “Vogelwarte Helgoland” in Wilhelmshaven sheds light on the genetic basis of this remarkable skill.

The researchers compared the genomes of hundreds of bird species and discovered significant evolutionary changes in a specific protein, cryptochrome 4, found in the birds’ eyes. This protein is believed to be the magnetoreceptor responsible for the birds’ ability to sense Earth’s magnetic field and navigate accordingly.

The study builds on previous research that revealed the role of cryptochrome 4 in magnetoreception, a complex quantum mechanical process that occurs in specific cells in the retinas of migratory birds. The team’s findings suggest that cryptochrome 4 is highly sensitive to magnetic fields in migratory birds, such as robins, compared to resident species like chickens and pigeons.

Furthermore, the researchers observed that the gene sequence for cryptochrome 4 has evolved rapidly in certain groups of birds, particularly in passerines, indicating adaptation to specific environmental conditions. This specialization could be linked to magnetoreception, similar to the role of light-sensitive pigments in the eye.

Notably, the study also revealed that cryptochrome 4 has been lost in tropical bird clades such as parrots, hummingbirds, and Tyranni (Suboscines), suggesting that it may not be vital to their survival. This opens up new avenues for investigating alternative orientation and navigation mechanisms in these birds.

The research provides valuable insights into the genetic basis of magnetoreception in migratory birds. It raises intriguing questions about the evolution of sensory proteins and the diversity of navigation mechanisms across different bird species. The findings have been published in the journal Proceedings of the Royal Society B: Biological Sciences, marking a significant contribution to our understanding of avian navigation.

References

• Kehse, U. & Carl von Ossietzky Universität Oldenburg. (2024, April 24). How evolution has optimized the magnetic sensor in birds. Phys.Org; Carl von Ossietzky Universität Oldenburg. https://phys.org/news/2024-04-evolution-optimized-magnetic-sensor-birds.html
• Langebrake, C., Manthey, G., Frederiksen, A., Lugo Ramos, J. S., Dutheil, J. Y., Chetverikova, R., Solov’yov, I. A., Mouritsen, H., & Liedvogel, M. (2024). Adaptive evolution and loss of a putative magnetoreceptor in passerines. Proceedings of the Royal Society B: Biological Sciences, 291(2016), 20232308. https://doi.org/10.1098/rspb.2023.2308