At least part of that protection is conferred by the DNA-binding protein Dsup [1]. So minimally the cost is 1) producing the (unique, as far as we have searche

At least part of that protection is conferred by the DNA-binding protein Dsup [1]. So minimally the cost is 1) producing the (unique, as far as we have searched) protein, and 2) dealing with DNA which has Dsup bound to it. There is no free lunch, but it's actually a pretty interesting protein that seems to somehow sacrificially prevent double-stranded breaks of DNA by ionized radiation. It's likely not much more than a metabolic cost - though there is some possibility that it affects some gene regulation. When Dsup was put into mammalian cells it did confer to them protection from radiation damage. [1] https://serotiny.bio/notes/proteins/dsup/ https://serotiny.bio/notes/proteins/dsup/