INVESTIGATING POPULATION GENETICS AND SEASONAL VARIATION OF TRANSCRIPTION IN BROWN BEARS (URSUS ARCTOS)
Many brown bear (Ursus arctos) populations globally are geographically isolated and face threats from human land use. As a changing climate increases temperatures globally, particularly in the northern latitudes where most brown bears are found, the threats facing these populations are increasing. A...
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| Other Authors: | , , , |
| Format: | Doctoral or Postdoctoral Thesis |
| Language: | English |
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Washington State University
2021
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| Subjects: | |
| Online Access: | https://doi.org/10.7273/000005504 https://rex.libraries.wsu.edu/esploro/outputs/doctoral/INVESTIGATING-POPULATION-GENETICS-AND-SEASONAL-VARIATION/99900599557201842 https://rex.libraries.wsu.edu/view/delivery/01ALLIANCE_WSU/12353313220001842/13353313210001842 |
| Summary: | Many brown bear (Ursus arctos) populations globally are geographically isolated and face threats from human land use. As a changing climate increases temperatures globally, particularly in the northern latitudes where most brown bears are found, the threats facing these populations are increasing. As a hibernating species brown bears physiology is uniquely tied to annual cycles in weather and food availability and changes in those patterns may disrupt this unique physiology. In my dissertation I worked to further our understanding of hibernation physiology. Improving this understanding may prove beneficial to humans as well as several aspects of hibernation physiology can act as biological models for human pathologies, from muscle wasting, to heart disease, to metabolic syndrome. Using RNA sequencing I evaluated muscle, liver, and adipose tissue in hibernating and active bears to further understand the molecular changes that drive the changing phenotypes between seasons. As bears become insulin resistant in hibernation these three tissues were selected due to their roles in glucose uptake in response to insulin. I found that across all three tissues over 10,000 genes were differentially expressed in hibernating animals compared to non-hibernating animals, with adipose tissue having more genes differentially expressed (6,139) than the other two tissues. I followed up these results by evaluating RNA changes that occur in adipose tissue in vitro when cells and the serum applied are collected either in hibernation or active season. I found that growing hibernation cells in hibernation serum resulted in a dramatic change in gene expression from active cells grown in active serum. A further serum treatment, in which hibernating bears were fed glucose for ten days before serum was collected, resulted in hibernation cells reverting gene expression nearly completely to active season gene expression profiles. Finally, I used population genetic analysis to evaluate the effect that human activity in wild bear country may be ... |
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