Sinergistički efekat genomskog i sredinskog stresa u dve populacije Drosophila subobscura
The synergistic effect of genomic and environmental stress in two populations of Drosophila subobscura
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The subject of this dissertation is population genetic analysis of synergistic effect of genomic and environmental stress in model species Drosophila subobscura. Individuals sampled from two ecologically distinct habitats, and their hybrids with different levels of genome heterozygosity (intra-line, intra-population and inter-population hybrids) were exposed to elevated concentrations of lead, aiming to test hypothesis of heterozygote superiority in stressful conditions and detect population specific response to lead pollution. Synergistic effect of stress was evaluated at three levels: population - through analysis of fitness components (development time and egg-to-adult survival), morphological - through analysis of variability in the wings size and biochemical – through the expression of heat shock protein. The results showed a reduction of all investigated traits in inbred individuals and their increase in those with higher levels of genome heterozygosity, confirming the hypothesis of heterozygote superiority which intensifies under stressful conditions. Analysis of fitness components indicates synergistic effect of genomic and environmental stress, and variance in wing size shows statistical significance, since the greatest reduction of all traits was observed in inbred groups. Population specific response to lead pollution was not detected, but significant influence of female origin on the outcome of between-population hybridization under stressful conditions was observed. It can be concluded that the maintenance of genetic variation is important for the survival of populations in changing environments, and even low levels of inbreeding lead to decline in adaptive value, especially in stressful environments.
Keywords:Drosophila subobscura; Environmental stress; Genomic stress; Synergistic effect; Lead pollution; Fitness components; Wing size; Hsp expression
Source:University of Belgrade, Faculty of Biology, 2016, 1-130
- Dynamics of gene pool, genetic and phenotypic variability of populations, determined by the environmental changes (RS-173012)