[Chromosome aberrations in different tissues of the murine rodents and amphibians from radionuclide-contaminated regions of Belarus]. / Khromosomnye aberratsii v razlichnykh tkaniakh myshevidnykh gryzunov i amfibii iz zagriaznennykh radionuklidami raionov Belarusi.

Cytogenetic investigations of amphibian and rodent populations from the contaminated by radionuclides regions of Belarus was conducted. A significant increase in the levels of cytogenetic anomalies in bone marrow cells and intestinal epithelium of amphibians and rodents, the levels of alveolar macrophages of rodents, and micronuclei in peripheral blood erythrocytes of amphibians was revealed. Presence of chromosome type aberrations indicates that radiation as a mutagenic factor was involved. No strict relationship between the levels of contamination of the area and levels of cytogenetic anomalies was found.

[The genetic monitoring of populations of brown frogs inhabiting radionuclide-contaminated regions of the Republic of Byelarus]. / Geneticheskii monitoring populiatsii burykh liagushek, obitaiushchikh v zagriaznennykh radionuklidami raionakh Respubliki Belarus'.

Genetic monitoring of brown frog populations inhabiting radiocontaminated areas of Belarus (contamination range: 177-2331 kBq/m2 for 137Cs; 3.7-284 kBq/m2 for 90Sr) has shown that the frequency of aberrant metaphases in bone marrow cells of animals from the contaminated areas is 3 to 10 times as much as that of the control, aberration load of cells being also higher. The aberration spectrum differs from a spontaneous one. There is no strict dependence of the yield of cytogenetic damages on the contamination.

[Polymorphism for supernumerary chromosomes in populations of Rana temporaria L]. / Polimorfizm po dobavochnym khromosomam v populiatsiiakh Rana temporaria L.

Occurrence of B-chromosomes in four populations of Rana temporaria L. in Minsk, its suburb and Berezinskii biosphere reserve has been studied. The percentage of individuals with B-chromosomes and the average number of B-chromosomes per genome are shown to multiply increase in the population inhabiting for 40 years in the region polluted with waste products. The results obtained are discussed from the standpoint of the action of mechanism for the accumulation of additional chromosomes due to environmental pollution.

[Effectiveness of selection for thorax length in model Drosophila populations in chemical mutagen exposure]. / Effektivnost' otbora po dline grudi v model'nykh populiatsiiakh drozofily pri vozdeistvii khimicheskim mutagenom.

Artificial selection for increasing and decreasing Drosophila thorax length was carried out over 20 generations. Chemical mutagen, dimethylsulfate (DMS) was regularly applied to enhance genetic variation in selected lines. It was determined that under the influence of mutagen the efficiency of selection for decreasing thorax length was much higher, while selection course for increasing thorax length was not affected significantly. Regression coefficient of responses to selection, general for males and females, was equal to b = -0.035 +/- 0.004 for lines of negative direction of selection when the mutagen was applied and -b = -0.023 +/- 0.004 without mutagenesis; for lines of positive direction b = 0.026 +/- 0.005 and b = 0.024 +/- 0.005. Fitness component variation by artificial selection was studied. A complex correlation was detected between direction of selection, the shift value of model quantitative character and fitness component variation by selection. The main factor stimulating a sharp drop of average fitness of lines appeared to be the influence of directional artificial selection. The regular treatment by a moderate dose of the mutagen did not affect markedly the average fitness variation of selected lines.