[en] The method of elastoviscosimetry was used to study the dose dependence of induction of DNA double-strand breaks both in the wild type E, coli and the repair deficient recABC strain exposed to γ-radiation. It was shown that with regular techniques of preparing cell cultures for the time lapsed after irradiation till lysis, a marked enzymatic degradation of DNA occurs exaggerating the true number of DNA double-strand breaks. Due to this process a real picture of repair of DNA double-strand breaks in the wild type cells is distorted. On the basis of the data obtained it is concluded that the true double-strand breaks remain unrepaired which is the main reason for lethality of the wild type cells, not the repair-deficient recABC mutant