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Summary GENE POOL CHANGES AFTER ECOLOGICAL CATASTROPHE |
Summary
GENE POOL CHANGES AFTER ECOLOGICAL CATASTROPHE
Chernobyl’s example
V.I.Glazko, T.T.Glazko Institute of Agriecology and Biotechnology UAAS, Kiev, Ukraine
Analysis of the population-genetic consequences of technogenic catastrophes, e.g., Chernobyl, represents special interest in connection with development of global ecological changes and rising technogenic contamination.
The life on the Earth has arisen and developed in the presence of the natural radioactive background (RB), a constant external abiotic factor. The availability of the territories on Earth, in which RB differs dozens and hundred times from world average, testifies the relativity of concepts of injuring dozes of ionizing radiation. Sudden significant elevation and persistence of radioactive exposure caused by human error as in Chernobyl can be considered a “changed” ecological condition. Not the new local elevated RB, but abruptness of the change, is a real long-term problem related to Chernobyl accident.
The “novelty” of ecological conditions caused by human activity is the specific trait of modern time. Chernobyl serves as invaluable model for the study of the effects of fast changes in the environment on the well-being of humans and ecosystems.
We investigated the laboratory lines of mice, exposed to ionizing irradiation in special vivarium near Chernobyl’s NPP, voles species, trapped in Chernobyl’s zone; cattle herd, in different generation reproduced under increased level of ionizing irradiation in experimental farm near Chernobyl’s NPP and children, which exposed to the same doze of ionizing irradiation but in different mode: acute (in utero) and chronic ones.
In result we obtained data, that increased level of ionizing radiation did not induce qualitatively new damages of the genetic material, but increased its instability in those species or at those genetic anomalies that have been determined to be apriori more prone to appearance of genetic defects than others. No increase in the quantity of constitutive mutations (mutant organisms) in investigated genes or chromosomes in analyzed species (cattle and Rodentia species) was observed. We revealed the acute decrease in fertility in first cow generation which was born in Chernobyl (in number of calf per one cow per one year). Observed by us the increase of frequencies of cytogenetic anomalies in blood cells of children (14 – 16 years age) who received the doze of ionizing radiation in utero and our data about the cattle fertility decrease, allowed to suppose, that children exposed to low dozes of ionizing radiation in utero, could face reproductive problems in the future.
In generations of cattle, disturbance of equiprobable transmission of alleles of a number of molecular genetic markers, increase of heterozygosity and radio resistance were observed.
In family analysis the changes of genetic structure in exposed to ionizing irradiation cattle generations the shift of gene pool from typical for specialized parent dairy breed Holstein to that characteristic for the less specialized breeds was revealed (decrease in level of specialization)
It is important to note that observed shift of a genetic structure in cattle generations in the direction of the less specialized forms was in agreement with the literature data about a decrease of a number of behavioral specialized functions in voles (more primitive relatives of burrows) in conditions of increased radio nuclide contamination, and also with the data of the Danish investigators about disturbance of functions of associative thinking in Danish children after the first air explosions of nuclear bombs and after Chernobyl accident.
All these appearances corresponded to a rule of I.I. Shmalgauzen that any change of the environment lead to preferable reproduction of the more primitive forms within a species. Thus, the main problem after the Chernobyl’s catastrophe, as well as other ecological changes, lies not in the occurrence of the new mutant organisms, but in the long-term changes of the genetic structure of populations and, accordingly, in the appearance of the new interspecies interactions between the less specialized (marginal) representatives of each species in species communities.
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