Evolucija starenja kod laboratorijskih populacija Acanthoscelides obtectus: uloga mitohondrija i oksidativnog stresa
Evolution of ageing in laboratory populations of Acanthoscelides obtectus: role of mitochondria and oxidative stress
Doctoral thesis (Published version)
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According to the evolutionary theory of ageing, age-specific decline in survival is the result of decreasing intensity of natural selection after the onset of reproduction. The evolution of ageing may be explained by two different, but not mutually exclusive, genetic mechanisms: antagonistic pleiotropy (AP) and mutation accumulation (MA). In accordance with evolutionary theory of ageing, two sets of the seed beetle (Acanthoscelides obtectus) experimental lines selected for more than 170 generations for early (E regime) or late (L regime) reproduction, show divergence in longevity and ageing patterns, as well as in other preadult and adult life history traits. Evolution of long life in L regime is predominantly based on antagonistic pleiotropy gene effects, while mutation accumulation plays important role in evolution of short life in E regime. By exposure of E and L beetles to two pesticides (paraquat and tebufenpyrad) that generate free radicals, it was confirmed that extended longevity in L beetles (especially in females) was associated with higher oxidative stress resistance. Additionally, since mitochondria are main site of free radical and energy production, effects of age-specific laboratory selection on mtDNA, nDNA and their epistatic interaction were assessed. Genotyping of mitochondrial COI gene and nuclear microsatellite loci showed that selection in E and L regimes led to divergent evolution of mtDNA and nDNA gene pools. Mitonuclear coevolution was investigated using mitonuclear introgression lines in which E and L mitochondrial genomes were expressed in both E and L nuclear background. It was found that lines with disrupted mitonuclear interactions had lower activity of the mitochondrial electron transport chain complexes and lower preadult performance.