Magister Scientiae - MSc / This thesis explores species-level phylogenetic relationships of the African cycad genus
Encephalartos, which is one of the eleven genera of cycads. The genus is confined to
Africa and comprises approximately 65 species, 38 of which are found naturally in South
Africa. The phylogenetic studies on Encephalartos to date still result in many unresolved
polytomies so it is not possible to fully understand the relationships between different
taxa. In this study, AFLPs were used together with DNA sequencing to reconstruct the
phylogenetic relationships of the genus. This study is the first to be presented with aims
of resolving the relationships of Encephalartos using AFLPs together with DNA
sequences. Total DNA was extracted from accessions sampled from the Kirstenbosch
Botanical Garden and the Montgomery Collection, representing the majority of
Encephalartos species listed in the most recent world list of cycads. Sequences of the
trnL intron, rpoC1, ITS 1, ITS 2, and AFLP profiles from two sets of selective primers
were used to reconstruct the phylogenetic relationships within the genus using maximum
parsimony methods. As in earlier studies, unresolved polytomies were recovered from the
sequencing data. The AFLP trees have some resolution but CI and RI indices were low
indicating high levels of homoplasy in the data. The relationships resolved by this study
for all the data sets separately and combined were different to those previously suggested
for the genus. The biogeography of Encephalartos is also investigated by habitat
optimization of the genus to estimate the origin of the genus with respect to its current
distribution. / South Africa
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uwc/oai:etd.uwc.ac.za:11394/2258 |
| Date | January 2007 |
| Creators | Mabunda, Makhegu Amelia |
| Contributors | Weitz, Frans, Reeves, Gail, Donaldson, John, Faculty of Science |
| Publisher | University of the Western Cape |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Rights | University of the Western Cape |
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