Take the 2-minute tour ×
Biology Stack Exchange is a question and answer site for biology researchers, academics, and students. It's 100% free, no registration required.

Ionizing radiation is damaging to DNA, but is there such a thing as a safe dose below which no DNA damage could occur? I'm not asking about a minimum safe dose overall, just whether or not there's an amount of ionizing radiation so small that the cell wouldn't even "notice" it if it were absorbed. Suppose I have, say, a fertilized egg cell on a petri dish. Would a single stray x-ray photon absorbed by the cell be enough to destroy it before it could reproduce? Is most DNA damage from x-rays due to the action of single photons, or from multiple ones being absorbed at the same time?


share|improve this question
The problem with answering your question accurately is, one, the absorption of a phtoton is a quantum mechanical phenomenon with almost a random chance of happening, and two, once absorbed, a lot of photophysical processes can occur, mutation being only a small part of the available options. Thus, yo quantify the threshold amount of radiation for mutation might not be possible because a lot of variables are involved. –  Satwik Pasani Feb 5 at 2:46
Interesting. I had thought it was as simple as the ionization energies of the atoms in DNA, but I guess I was wrong. –  Joel Feb 5 at 3:09
I think its possible - specifically if the photon caused a particular DNA break which was not reparable by the Cell's defenses, but that would be incalculably rare. Even most DNA breaks are repaired without incident. –  shigeta Feb 5 at 14:38

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Browse other questions tagged or ask your own question.