[Mathematical analysis of genetic effects of low doses of ionizing radiation]

The comparative study of effects of low doses of radiation on peripheral blood lymphocytes of persons occupationally exposed to radiation and non-exposed ones was carried out. The main attention was paid to radio-adaptive response forming under consistent exposure to low (0.05 Gy) and damaging (2 Gy) doses of gamma-irradiation. Noticeable heterogeneity in capacity for adaptive response forming in occupational group was revealed. The mathematical model adequate to experimental material was constructed using Kohonen neuronets.

[Genetic analysis of recessive lethal mutations induced by the influenza virus in the X chromosome of Drosophila melanogaster]

Mutagenic potential of the influenza virus was evaluated. Based on its capacity of inducing recessive lethal mutations in the X chromosome of Drosophila melanogaster, the influenza virus can be classified as a moderate-activity mutagen. Its mutagenicity does not depend on ability to reproduce in the cell system. This virus was shown to disrupt formation of the wing, particularly wing vein M1 + 2. Cytogenetic examination of polytene X chromosomes bearing recessive lethal mutations in Drosophila salivary glands did not reveal chromosome rearrangements. These lethals are assumed to be small deletions or point mutations. The determination of the lethal activity stage of these mutations showed that they disrupt the expression of genes functioning at various developmental stage of Drosophila. Two of them were conditionally lethal (temperature-sensitive). Two of 15 mutations analyzed were mapped to region 2B9-10-3C10-11.

[Frequency of chromosome aberrations in residents of the Semipalatinsk Oblast]

Cytogenetic analysis of the population of the Beskaragai district of the Semipalatinsk oblast adjacent to the territory of the nuclear test site was conducted by means of an ecological genetic questionnaire and cytogenetic examination of metaphase chromosomes. An increase in the total mutation level in the region was observed. The frequency of chromosome aberrations among the population of the Beskaragai district (3.2%) was statistically significantly (about 1.5 times) higher than the background levels in the clear regions (from 1 to 2%). Furthermore, the frequency of aberrations in adolescents was comparable with that in the adults. The spectrum of chromosome aberrations pointed to a significant contribution of radiation component to the mutagenesis.