Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain
the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in
Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles
Iron-binding proteins could help rainbow trout to navigate.
Many migrating animals use Earth’s magnetic field as a guide, but how they sense magnetic stimuli at the molecular level has been unclear. Cells containing iron-oxide crystals called magnetite that are sensitive to magnetic fields may be involved. To look for genes linked to magnetoreception, Robert Fitak at Duke University in Durham, North Carolina, and his colleagues exposed rainbow trout (Oncorhynchus mykiss) to a magnetic pulse and studied how gene expression in their brains changed compared with that in an unexposed control group. Fish subject to the magnetic stimulus showed increased expression of ferritin genes, which encode proteins that store iron.