[Structural changes in the marker chromosome of rhesus macaques subjected to irradiation].

Using 48 Macaca rhesus undergone acute single does and prolonged small dose daily irradiation, a long-term preservation of reconstructions in the pair of marker nucleolus-forming chromosomes has been shown. The animals were examined in different periods from irradiation, ranging from 3 months to 16.5 years. The frequency of retained reconstructions in the long arms of chromosomes was reliably above the frequency of alterations in the short arms. Reconstructions in the long arms of the marker chromosome were seen in the heterochromatin area after differential chromosome staining. Alterations in the functionally active area of the short arms of the marker chromosome retained extremely rarely being observed only in monkeys that survived through long-term small-dose irradiation.