Using Microarrays to Quantify Stress Responses in Natural Populations of Coral
Edge, Sara Elizabeth
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Coral reefs are one of the world s most valuable ecosystems but are declining at an accelerating rate. Common stressors impacting coral health include elevated temperatures, changes in light intensity, sedimentation, and increased exposure to pollutants. Traditionally, physiological responses have been measured to assess coral health but usually do not identify the stressor or the underlying mechanisms causing a response. In addition, coral may be stressed beyond recovery by the time a physiological response is observed. Changes in gene expression are key elements of the stress response, usually occur before physiological damage is evident, and can be directly related to the causative agent of stress. My research focuses on detecting sublethal responses to stress in Scleractinian coral using genetic biomarkers and gene expression profiling. Through the application of molecular technology, I have developed a coral stress gene microarray to investigate the responses of coral to various stressors. Results from controlled laboratory exposures provide evidence for unique gene expression profiles associated with specific stressors. Results from field studies reveal the feasibility of using array technology to investigate changes in gene expression of natural coral populations across time and between sites. For example, the array has been used to detect stress in coral populations related to seasonal events, such as precipitation as well as point source stress, such as xenobiotics. The temporal and spatial regulation of specific genes within a genome determines the metabolic activity of an organism and can be used to identify changes in cellular responses to various stimuli. These cellular events precede population-level changes and could be useful biomarkers if linked to specific physiological or ecological events. This research is important because it identifies stress at a sub-lethal level and can aid resource managers in decision making by prioritizing the stressors impacting coral reefs.