Inbreeding effects in Drosophila congenic strains: the influence of genetic background of different origin

Aim. To compare reproductive indices and stress resistance of Drosophila at outbreeding and inbreeding. Methods. Drosophila melanogaster congenic strains with incomplete development of the radial wing vein – radius incompletus – were used: the laboratory one and the strain, in which the mutation was placed into the genetic background of wild type strain, which originates from the natural population from radiation contaminated territory. Before the experiment strains have passed 65 generations of inbreeding. Viability (number of individuals, pupa stage mortality), dominant lethal mutations frequency and life span of imago at starvation were analysed. Results. After inbreeding, there was a decrease in the frequency of dominant lethal mutations and an increase in viability of the strain, which originates from the natural population, and a decrease of mortality at the pupal stage in both strains. Decreased life span of imago at starvation has been shown only for the inbred strain, which originates from the natural population. Conclusions. Inbreeding for 65 generations has no significant negative effect on reproductive indices; reduction of stress resistance during inbreeding has been shown only for the strain, which originates from the radiation contaminated territory. Keywords: Drosophila, viability, dominant lethal mutations, life span of imago at starvation, inbreeding.