Genetic Consequences of the Chernobyl Accident for Belarus Republic

IntroductionNumerous studies have shown that a great number of residents in Belarus, Russia and the Ukraine were exposed to radiation due to radioactive nuclides ejected from the Chernobyl reactor, which increased genetic load, manifested in particular, as chromosome aberrations (Lazjuk G.I. et al., 1990; Pilinskaya M.A. et al., 1994; Sevankaev A.V. et al., 1995). The increase was registered for unstable and stable, chromatid and chromosome types of aberrations (Stepanova E.I., Vanyurikhina E.A. 1993, Vorobtsova I.E., Bogomazova A.N., 1995, Sevankaev A.V. et al., 1995). Proceeding from the findings that the number of dicentric and ring chromosomes (which are the main indicator of radiation mutagenesis at chromosome level) was increasing simultaneously with the increase of other aberrations which are common for chemical mutagenesis (Pilinskaya M.A. et al., 1994; Lazutka J.R., 1996) and from the fact that actual mutation incidences exceeded the calculated figures for the doses obtained (Pilinskaya M.A. et al., 1992, Sevankaev A.V. et al., 1995), one can not exclude the possibility that chromosome aberrations found in the population affected by the Chernobyl disaster are caused not only by ionizing radiation but also by various mutagenes, and the doses based on physical dosimetry could be underestimated. It is quite obvious that the level of chromosome aberrations can be used as a biological indicator of harmful mutagenic effects on the organism. However, the method is not yet capable of (or only partially suited for) detecting the actual genetic risk even in the cases when aberrations are found in gametes, not in peripheral blood lymphocytes as usually done. The study of the dynamics of genetic losses, as spontaneous abortions and perinatal death due to inherited anomalies, and the study of the dynamics of malformed children births are probably the most reliable methods to determine genetic risk due to any mutagenic factor affecting the population, including ionizing radiation. This is related to the fact that there are a great sequence of events (gamete selection, preimplantation and embryonal death) occurring between gamete mutations (to say nothing about a somatic one) and births of children with congenital diseases. It is nearly impossible to count them and this leads to various