[en] The decay of the radioisotope ¹²⁵I into ¹²⁵Te is typically followed by the emission of two groups of approximately 10 electrons each. In deoxyribonucleic acid (DNA) with ¹²⁵I incorporated, these electrons produce various types of damage to DNA, e.g. single and double strand breaks. They occur through direct actions of physical tracks, or indirect actions of radicals produced in water. Among the direct actions one should consider not only the excitation and ionization of DNA by electrons but also the neutralization of highly charged ^125mTe ions with electrons from neighboring molecules. The present work begins with a detailed description of electron tracks with the use of the PARTRAC code, compares results with recent experiments, and concludes with a firm assessment of the contribution to the strand break yields from the neutralization effect. (orig.)