Date Awarded


Document Type


Degree Name

Master of Science (M.Sc.)




John P Swaddle

Committee Member

Helen Murphy

Committee Member

Daniel Cristol


The organic, methylated form of mercury (Hg), methylmercury (MeHg), is a highly toxic global pollutant that affects humans, wildlife, and ecosystem health. While exposure to high dosages of MeHg is often fatal, much less is known about the physiological effects of exposure to lower, sub-lethal dosages. Further understanding of how MeHg exposure alters organ performance at a cellular level is critical to understanding the health effects on both humans and wildlife impacted by environmental contamination. To assess the impact of MeHg on eukaryotic organisms, we tested how lifetime, dietary exposure impacts telomere length shortening in various tissues of the zebra finch (Taeniopygia guttata) at four early ages post-hatch. Telomere length is a recently popularized biomarker of biological aging and individual quality, influenced by both genetics and the environment. We used real time PCR to measure relative telomere length (T/S ratio) of brain, liver, kidney, heart, and red blood cells and explored interactions between ages and dietary treatment. We predicted that birds exposed to an environmentally relevant level of Hg would have reduced telomere lengths than compared to controls due to increased oxidative stress and subsequent cellular damage. Rather, in all tissues and virtually all ages, Hg exposed birds had longer telomere lengths, suggesting alterations in telomere maintenance pathways, inhibited cellular proliferation, and/or MeHg-induced rapid selection.



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Available for download on Monday, January 20, 2025