Here's a great video explaining DNA damage and repair mechanisms. It's from Prof. Jim Boyne of the University of Bradford. Unfortunately, what that means is that in addition to technical jargon, you've got heavily accented technical jargon. If you're not up on basic molecular biology, you might want to pass. If you're wishy-washy you might want to read this first.
He does a good job (though not intentionally) of addressing a common health physics denialism claim that goes something like:
1. We have lots of DNA damage happening all the time.
2. Some event happens causing low dose radiation exposure.
3. There is no increased risk from the radiation because of 1.
Mathematically, it's like claiming 100,000 + 1 = 0, whereas the correct answer is 100,001.
I recommend you enjoy it with a cup of tea and some biscuits: