MONDAY, 5 FEBRUARY 2024Every year, robins fly over thousands of kilometres, only to return months later to exactly the same spot where their nest waits patiently for them. While this may look like a prodigious feat of memory, today we understand that this is actually due to their extraordinary power to sense the Earth’s magnetic field. But how?
To our current understanding, magnetic fields are sensed when a small molecule called “flavin adenine dinucleotide” (FAD), present in almost all species, is exposed to light. As a result, it generates unpaired electrons, acting as tiny magnets. These are transferred in neurons along special proteins known as “cryptochromes”, which spread information about how to orient. This year, scientists from the University of Manchester have shown that such a complex architecture may not be necessary, and that FAD alone might be a molecular compass in itself.
The team measured the electrical signals responsible for magnetoreception in fruit flies that had been genetically modified to lack a portion of or the entire cryptochrome. They found that neurons responded to light as well as to a small applied magnetic field in the presence of high concentrations of FAD, even with no trace of the protein.
Although we thought cryptochromes were indispensable for magnetoreception, the outcomes of the study imply that in fact, they are solely transducers. This means that potentially every living being - humans included - might be able to “feel” where due North is if empowered with (as yet unphysiological) levels of FAD.
Article by Andrea Rogolino
Image credit: Calsidyrose
Image licence: Attribution (CC BY 2.0)
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