PROLONGED STRESS INDUCES MUTATIONS AND PROVIDES
UNSPECIFIC ADATATION OF DROSOPHILA POPULATIONS.
Mosse I.B., Glushkova I.V, Aksyutik T.V.
Institute of Genetics and Cytology, National Academy of Sciences of Belarus, Minsk,
Belarus.
Earlier we have shown adaptation of natural drosophila populations from
radiocontaminated regions of Belarus to mutagenic effect of radiation. It was interesting to
study the possibility of remaining this adaptation in a number of generations after radiation
exposure termination. This question was investigated in natural drosophila populations
caught in 2000-2001 in the settlement Vetka of Gomel region (24 Ci/km2) and in Berezinsky
reserve (the control) with the test of dominant lethal mutations. For genetic resistance
evaluating males from the populations studied were exposed to acute γ-radiation 30 Gy.
The population from the settlement Vetka proved to be more adapted to radiation
exposure than the population from Berezinsky reserve. This adaptation was shown to be
unspecific – irradiated population became more resistant to chemical mutagen
ethylmethansulfonate as well as to radiation.
Then the population samples were kept under laboratory condition without irradiation.
for 8 generations. It should be noted that the mutation level in both populations increased at
keeping under such conditions. Acute irradiation 30 Gy was used after 8 generations.
Adaptation of Vetka population to irradiation remained.. Besides the control population
became also more resistant to ionizing radiation but its adaptation was not so expressed than
that of Vetka population. It means that keeping of natural drosophila populations under
laboratory conditions is a strong stress (limited space, overpopulation, other temperature and
light conditions), which increases mutation process and induces unspecific adaptation.
These facts should be considered in studying dynamics of the mutation level during
radionuclide removal in animals caught in radiocontaminated regions and placed in vivarium
conditions.