In mammals like us, IR causes DNA breakage which is either repaired or the cells undergo a programmed cell death (if able to). This becomes a standard treatment for cancer (and other diseases). However, a new study shows in a particular strain of bacteria (Deinococcus radiodurans) which can handle much higher doses of radiation, the secret is not the DNA damage, but is due to protein damage due to reactive oxygen species. This may have implications for radiation treatment; traditionally, it is thought that the only effect of IR is DNA damage, now we know protein damage also plays a role, and in radiation resistant cancers, the secret may be due to enhanced dna repair proteins.