What is the statistical relationship between radioactivity and mutation rate? This question tries to narrow down the scope of that question. What is the statistical relationship between radioactivity and mutation rate? By how much would the mutation rate be lowered in a idealized world were radioactivity is absent?

According to this wiki page , the average background radiation is 3.01 milli-Sievert per year (including natural and artificial sources). This equals 0.301 rad.

I found a short letter to nature that says the average forward mutation rate in human is 2.6 * 10^-7 per locus per rad = 2.6 mutations per ten million bases. Also it say that this mutation rate is quite uniform among species. The size of the human genome is approximately 3.2 gigabases. So doing a quick maths: (2.6*3.2*100)*0.301 = 250.432 mutations per year per human. This is an approximation because I rounded the size of the human genome to 3.2 gigabases. Also this doesn't mean that we actually acquire this amount of mutations because we have repair mechanisms.