The authors regret having incorrectly written in equation (7) that the fraction of surviving cells (SF) is obtained using the natural logarithm of the negative value of the number of lethal lesions L_f. The natural logarithm must be replaced by the exponential function as follows: [Formula presented] Although the equation is incorrectly written in the paper, its correct expression has been used in the results of the analysis shown in Figure 4. This error has no impact on the other results and conclusions of the paper. The authors would like to apologise for any inconvenience caused.