Any violation of the homologous chromosome DNA repair leads to the genome instability, characteristic for hereditary syndromes and for aging cells. Using low doses of ionizing radiation (3-10 cGy) we have found any transference of the homologous centromere loci of the chromosome 1 (1q12) from the periphery to the cen- tre of the nucleus in the lymphocytes of young healthy donors. The same effect was found after any influence of RNA-polymerase inhibitor a-amanitine. Some changes in the chromatin structure during aging (70-80 years old patients) result in the difficulties in chromosome displacement, accompanied with any trouble in the appro- achement of the homologous chromosome loci as an answer to low doses of radiation.