> Zhdanova suspected that the melanin of these fungi was acting as a shield against ionising radiation.

Wouldn't that be very easy to measure? My guts tell me that using the melanin as a shield against gamma radiation has a negligible effect, if any at all.

You are assuming a molecule good at shielding against UV light is probably a poor shield against gamma rays, many orders of magnitude shorter wavelength. That sounds probable ...

But how about the theory that systems to clean up smashed up proteins from UV light is also good to clean up smashed up proteins from gamma radiation?

And one of the parts of that system, or upregulated with that system, is melanin.