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Lack of polymorphism suggests a recent bottleneck of Aloidendron pillansii: Exploration into the population of Aloidendron pillansii from phylogeographical analysis of molecular data
Includes bibliographical references.
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| Other Authors: | |
| Format: | Thesis |
| Language: | English |
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Department of Biological Sciences
2015
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| _version_ | 1867613185908932608 |
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| access_status_str | Open Access |
| author | Josephs, Randall Evan |
| author2 | Hedderson, Terry A |
| author_browse | Hedderson, Terry A Josephs, Randall Evan |
| author_facet | Hedderson, Terry A Josephs, Randall Evan |
| author_sort | Josephs, Randall Evan |
| collection | Thesis |
| description | Includes bibliographical references. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/12769 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:32:08.355Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2015 |
| publishDateRange | 2015 |
| publishDateSort | 2015 |
| publisher | Department of Biological Sciences |
| publisherStr | Department of Biological Sciences |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/12769 Lack of polymorphism suggests a recent bottleneck of Aloidendron pillansii: Exploration into the population of Aloidendron pillansii from phylogeographical analysis of molecular data Josephs, Randall Evan Hedderson, Terry A Hoffman, M T Botany Includes bibliographical references. The Karoo-Namib is a species rich region in which many iconic and keystone species are found, such as Aloe pillansii. The recent population history of A.pillansii is poorly understood. However the suggested climatic shifts that occurred throughout the Holocene era may have affected its distribution, demographics and gene flow. The glacial/interglacial refugia hypothesis predicts that the southernmost population served as a refuge population and that the subsequent expansion of the population was to the north in concert with the northward expansion of the winter rainfall regime. I evaluated this hypothesis by linking the molecular data (cpDNA and nDNA) of 84 individuals from three main populations with phylogeographical techniques. Based on the combination of percentage of mutations percentage per million years range and the chloroplast sequences, it has been estimated that the time of divergences was between 3.45 to 16.67 million years ago. The molecular analysis identified a significant lack of genetic diversity within and among the three dominant populations of A.pillansii. This suggests that the species experienced a severe bottleneck event prior to its recent expansion that has been suggested to have occurred within the time frame of 100 to 1000 years ago. This pattern is compared with its sister taxa Aloe dichtotma, which possesses variation within and among its populations. The lack of genetic variation evident within A. pillansii leaves it vulnerable to future climate shifts as low genetic variation within a species lowers the ability of that species to adapt to both environmental and climatic changes. This thesis has provided a brief insight into the population history of A.pillansii, but further research is needed. 2015-05-06T14:23:34Z 2015-05-06T14:23:34Z 2014 Bachelor Thesis Honours BSc (Hons) http://hdl.handle.net/11427/12769 eng application/pdf Department of Biological Sciences Faculty of Science University of Cape Town |
| spellingShingle | Botany Josephs, Randall Evan Lack of polymorphism suggests a recent bottleneck of Aloidendron pillansii: Exploration into the population of Aloidendron pillansii from phylogeographical analysis of molecular data |
| thesis_degree_str | Bachelor's / Honours |
| title | Lack of polymorphism suggests a recent bottleneck of Aloidendron pillansii: Exploration into the population of Aloidendron pillansii from phylogeographical analysis of molecular data |
| title_full | Lack of polymorphism suggests a recent bottleneck of Aloidendron pillansii: Exploration into the population of Aloidendron pillansii from phylogeographical analysis of molecular data |
| title_fullStr | Lack of polymorphism suggests a recent bottleneck of Aloidendron pillansii: Exploration into the population of Aloidendron pillansii from phylogeographical analysis of molecular data |
| title_full_unstemmed | Lack of polymorphism suggests a recent bottleneck of Aloidendron pillansii: Exploration into the population of Aloidendron pillansii from phylogeographical analysis of molecular data |
| title_short | Lack of polymorphism suggests a recent bottleneck of Aloidendron pillansii: Exploration into the population of Aloidendron pillansii from phylogeographical analysis of molecular data |
| title_sort | lack of polymorphism suggests a recent bottleneck of aloidendron pillansii exploration into the population of aloidendron pillansii from phylogeographical analysis of molecular data |
| topic | Botany |
| url | http://hdl.handle.net/11427/12769 |
| work_keys_str_mv | AT josephsrandallevan lackofpolymorphismsuggestsarecentbottleneckofaloidendronpillansiiexplorationintothepopulationofaloidendronpillansiifromphylogeographicalanalysisofmoleculardata |