Populations under stress : analysis on the interface between ecology and evolutionary genetics in nematodes

摘要: Human activities increasingly affect the natural environment. Consequently, many organisms are confronted with environmental conditions different from ones they evolved in and experience stress. Environmental stress affects various levels of biological organization (e.g. cell, life-histories, population, community, ecosystem) concerns time-spans. Therefore, to understand mechanisms behind responses consequences for systems requires incorporation multiple scientific disciplines. In this thesis I incorporate frameworks ecology evolutionary genetics investigate effects long-term on populations. addition, provide resources study genetic basis stress-related traits within QTL approach. Nematodes were selected as research subjects because their wide distribution, importance major ecological processes, such decomposition, ease laboratory handlings analysis. The part presented focused copper pH populations parthenogenetic nematode Acrobeloides nanus . Chapters 2, 3 4 present an extensive analysis experimental field where treatments applied a factorial design approximately 20 years ago. At first, considered combined stressors population biomass functional parameters secondary production turnover rate. Despite fact that anthropogenic common human-dominated environment, knowledge possible synergistic population-level is very limited. investigation reported chapter 2 possibly first using controlled system disentangle interactive parameters. results indicated negative high level low A. Surprisingly, showed no under same conditions. Overall, these findings demonstrated impact suggested might be more sensitive combination than measures or abundance. concluded realistic risk assessment would benefit analyses measures. 3, question whether observed changes life-history result adaptation local Reciprocal transplant- reaction norm experiments two extreme underwent adaptive divergence exposure. interpreted perspective biology asexual species contradict general view potential eukaryotes. They also demonstrate structure distribution shaped by events. 4, tested accompanied underlying architecture represented variance-covariance matrix ( G ). Within genetics, concept central it provides framework phenotypic evolution assumption stability over time. It acknowledged drift strong selection lead matrices, however time-spans promoting remain unknown. comparisons matrices profound response divergent imposed pointed less distinct likely attributed drift. Because all detected took place existence field, evolve rapidly These suggest enhance process dynamics represent feature species. second concerned bases other complex Caenorhabditis elegans Although there growing interest incorporating methods mainstream approaches model species, lack powerful hampers advancements field. 5, construction permanent, genome-wide library near-isogenic lines (NILs) parental lines, Hawaiian line CB4856 Bristol N2. All 91 NILs have single, short homozygous segment genome introgressed into N2 background total segments cover at least 95% length. chapter, one C. , clumping behaviour, both recombinant inbred (RILs) which resulted detection novel locus responsible variation trait. properties allow efficient accurate localization facilitate gene identification. 6, discussed most relevant them context fundamental problems (evolution sexual reproduction) issues (the use clonal toxicity testing). devoted section discuss role mapping research. Finally, made some suggestions regarding future directions strategies.