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Thesis
How Inbred is the Tasmanian Devil? A Meta-Analysis of Island Mammals (Sarcophilus harrisii)
Washington State University
Master of Science (MS), Washington State University
01/2021
DOI:
https://doi.org/10.7273/000005407
Handle:
https://hdl.handle.net/2376/119799
Abstract
Island species are vulnerable to extinction due to small population sizes and low genetic diversity, and their declines contribute disproportionately to global biodiversity losses. Despite decades of research studying inbreeding of island species, meta-analyses of relative levels of inbreeding and underlying environmental factors are rare. Such studies can help elucidate generalities regarding the influences on species’ genetic diversity and thereby help direct management toward ecosystem-wide efforts. One type of management strategy entails genetic rescue, or captive breeding or translocations aimed at maintenance or enhancement of genome-wide genetic diversity to facilitate adaptation potential, but recent efforts have begun to focus on targeted maintenance of current adaptive variation in response to specific threats. Endemic to the island of Tasmania, the Tasmanian devil is a species threatened with extinction and the focus of such management efforts. Devils are endangered owing to devil facial tumor disease (DFTD), a transmissible cancer, and historic population bottlenecks and potential inbreeding depression are thought to contribute to near-universal disease susceptibility. Diseased populations have declined more than 80%, elevating further inbreeding risk. Nonetheless, devils have shown rapid evolutionary responses to DFTD suggesting standing genetic diversity is adequate to respond to this intense selective pressure. In this thesis, I assess the overall genetic diversity of the Tasmanian devil pre- and post-DFTD to determine whether significant reductions in genetic diversity in the devil have occurred via DFTD-induced declines. Because current devil management includes genetic rescue, I assess devil genetic diversity relative to other island mammals in a meta-analysis of available literature. I found that the devil has not experienced a significant change in inbreeding or genetic diversity based on pre- and post-DFTD comparison. Relative to other island mammals, devils were intermediate in their inbreeding values. The meta-analysis results were mixed with some relationships aligning with island biogeography theory and some being contradictory. Generally, the meta-analysis provides evidence that distance to mainland, island area, animal mass, and species contribute to genetic diversity or population differentiation in island mammal species. Overall, this thesis provides a contemporary evaluation of island biographic factors and their contribution to genetic diversity estimates and applies a refined assessment of Tasmanian devil genetic diversity that can be used as a framework for future management.
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Details
- Title
- How Inbred is the Tasmanian Devil? A Meta-Analysis of Island Mammals (Sarcophilus harrisii)
- Creators
- Rachael Kane
- Contributors
- Andrew Storfer (Advisor)Jeremiah W Bush (Committee Member)Richard Gomulkiewicz (Committee Member)Lisette P Waits (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- School of Biological Sciences
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University
- Number of pages
- 104
- Identifiers
- 99900592154201842
- Language
- English
- Resource Type
- Thesis