The link between changes in life history traits and gene expression levels under stressful conditions in the waterflea Daphnia magna.

Natural populations are exposed to abiotic and biotic stressors, mostly interacting with each other. Insight into the different processes influenced by the combination of both types of stressors is thus important to predict and understand their influence on the ecosystem as a whole. The water flea Daphnia magna is an ideal model organism to examine the outcome of exposure to different stressors. The aim of our proposed research is to examine how gene transcription levels change under different stressful situations. Predation and parasitism are two important biotic stressors of Daphnia. As the impact of humans on the ecosystem worldwide is increasing, we also selected a pesticide as third stressor. Clonal and population transcription profiles after microarray analysis will be examined to search for candidate genes under specific stressful situations. Not only single stressor transcription profiles but also combined stressor profiles will be examined. Afterwards, RTQ-PCR will be used to screen more clones and more populations to broader our insight. Physiological biomarkers will be tested based on the candidate genes to understand the mechanisms underlying the differences in gene expression levels and the results observed in life history experiments performed during my PhD research.

Keywords:Combined stressors, Transcription profiles, Daphnia magna

Disciplines:Animal biology