Abstracts

Genetic Bases of Biodiversity

The dose dependence of the rate of g -induced transpositions and dynamics of the TE 412 pattern after g -irradiation in generations F₁, F₁₂, F₁₄₀ и F₁₇₀ were investigated in the isogenic strain N 49. It was shown that the dose dependence of transposition induction is very similar with early results of classical works of N.V.Timofeeff-Ressovsky et al.(1935) about induction of different mutations in drosophila by strong irradiation. It is supposed that the transposed copies of TE 412 "cure" the two-stranded DNA breaks produced by g -irradiation. It was shown that there is the phenomenon of prolongation of TE transposition induction during the first generations after treatment. In this period (F₁ ? F₁₂) there were the maximal rate of transpositions (l @ 2? 10^-2 events per TE copy per haploid genome per generation) and maximal number of heterozygous TE copies among the studied generations. In the latest generations (F_{140 ?} F₁₇₀) the rate decreased up to l ~ 10^-3 but not to the zero. In the population of the effective size N_e = 2000 individuals this corresponds to the state when l >> 1/ 4N_e, i.e. the transposition flow prevails over the flow of the random losses under genetic drift. These facts and some indirect data argue for the hypothesis that the rate of spontaneous TE transpositions is proportional to the average number of heterozygous TE copies per diploid genome.

This work was supported by the grants of RFBR (№№ 97-04-49232, 00-04-49499) and of the program "Russian Universities – Basic Researches" (№ 1760) of the Russian Federation Ministry of Education.

Note. Abstracts are published in author's edition

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