A molecular systematic study of the genus Encephalartos
| dc.contributor.advisor | Spies, J. J. | |
| dc.contributor.advisor | Oberholster, A-M | |
| dc.contributor.advisor | Vorster, P.J. | |
| dc.contributor.author | Coetzer, Maria Elizabeth | |
| dc.date.accessioned | 2017-04-05T09:28:15Z | |
| dc.date.available | 2017-04-05T09:28:15Z | |
| dc.date.issued | 2000-06 | |
| dc.description.abstract | English: The extant cycads (Cycadophyta) are divided into three families, with 11 genera (Johnson 1959, Stevenson 1990), and at least 210 species (Stevenson et al. 1995). In this study a molecular systematic study was done on the genus Stangeria T. Moore from the family Stangeriaceae, and the genus Encephalartos Lehm. from the family Zamiaceae. Fifty eight specimens representing 35 species of the genus Encephalartos, and one specimen from the genus Stangeria, Stangeria eriopus (Kunze) Nash were used. The effect and behaviour of hybrids in cladistic analysis were also investigated, such that they might be detectable during cladistic analysis. A pilot study of two molecular techniques, RAPD and DAF was done to determine the applicability, time effectiveness and most suitable primers for a molecular systematic study using these techniques. All the RAPD primers tested gave a high coefficient of similarity and adequate number of characters per specimen. The speed and simplicity of the RAPD technique, combined with the findings of the pilot study, made this an ideal method to generate a large amount of fingerprinting data for a phylogenetic assessment of the genus Encephalartos. Three variations of the DAF technique were tested in the pilot study i.e. simple DAFs, tecMAAP and multiplex DAFs. The coefficient of similarity was high in all the primers, with an increasing number of characters per specimen being generated. The multiplex DAF technique was the most successful, and most cost effective DAF variation. tecMAAP is also a very useful method in this study, but prior cleavage with restriction endonuclease, makes this a time consuming method. Multiplex DAFs combined with simple DAFs were, therefore, applied to more specimens in this study. Phylogenetic relationships were determined using the computer software PAUP, and the genetic distances between species were also determined, The RAPD and DAF cladograms show some correspondence, but also some discrepancies as expected because of the low resolution in the cladograms. Combining the data sets increased the resolution of the cladogram. The molecular results concur with morphological and biochemical studies that have been done on the species in this study, as observed in the close relationship between Encephalartos cupidus and E. eugene-maraisii, and E. umbeluziensis and E. villosus. The RAPD and DAF techniques were also successfully applied in hybrid analysis. An increase in hybrids to the cladistic analysis, do influence the tree topology, but not the cladogram resolution, with an increased tree length. Hybrids, therefore, are no more problematic cladistically than the increased inclusion of specimens. In this study the molecular techniques RAPD and DAF have proven to be a fast and cost effective method in successfully generating fingerprints for phylogenetic analysis. | en_ZA |
| dc.description.abstract | Afrikaans: Broodboom spesies (Cycadophyta) van die wêreld is geklassifiseer in 3 families, met 11 genera (John son 1959, Stevenson 1990), en omtrent 210 spesies (Stevenson et al. 1995). 'n Molekulêre sistematiese studie is op die genus Stangeria van die familie Stangeriaceae, en die genus Encephalartos van die familie Zamiaceae gedoen. Vyf-en-dertig Encephalartos spesies verteenwoordig deur 58 eksemplare, asook een Stangeria eriopus eksemplaar is in die studie gebruik om die filogenetiese verwantskappe van die spesies te bepaal. Die invloed van basters tydens kladistiese analises is ook bestudeer, met die hoop dat basters op die wyse geïdentifiseer kan word tydens analise. Die toepasbaarheid, tyd en mees informante inleiers van twee tegnieke, RAPD en DAF, is tydens 'n loodstudie bepaal. RAPD tegniek is vinnig, goedkoop en 'n hoë koëffisient van ooreenstemming dui aan dat die tegniek gebruik kan word vir 'n filogenetiese studie van die genus Encephalartos. Drie verskillend variasies van die DAF tegniek is getoets, nl. eenvoudige DAF, teeMAAP en multipleks DAF. Die inleiers wat getoets is, het 'n hoë koëffisient van ooreenstemming gehad en 'n toenemende hoeveelheid fragmente is waargeneem met die tegnieke. Alhoewel teeMAAP suksesvol in die loodstudie gebruik was, maak vooraf snyding met 'n beperkingsensiem die tegniek meer tydsaam. Multipleks DAF was die mees suksesvolle en koste effektiewe tegniek, en is saam met eenvoudige DAFs verder toegepas op meer eksemplare. Filogenetiese verwantskappe van die eksemplare is bepaal met behulp van die rekenaar sagteware PAUP. Die genetiese afstand tussen spesies is ook bepaal. RAPD en DAF resultate stem grotendeels ooreen, met verhoogde resolusie van die kladogramme wanneer die RAPD en DAF data gekombineer is. Die resultate van hierdie studie stem ooreen met resultate verkry vanaf morfologiese en biochemiese studies soos byvoorbeeld die verwantskap tussen Encephalartos cupidus en E. eugene-maraisii, asook E. umbeluziensis en E. villosus. Die invloed van basters tydens kladistiese analise het bewys dat basters nie die resolusie van kladogramme beïnvloed nie, maar wel die kladogram topologie. Kladogram lengte neem toe wanneer meer basters in die studie gebruik is. 'n Soort gelyke toename word egter ook gevind indien meer "tipiese" eksemplare gebruik word. In die studie is die molekulêre tegnieke RAPD en DAF suksesvol toegepas om die genetiese afstand en filogenetiese verwantskappe tussen spesies van die genus Encephalartos te bepaal. | af |
| dc.description.sponsorship | Foundation for Research Development | en_ZA |
| dc.identifier.uri | http://hdl.handle.net/11660/6054 | |
| dc.language.iso | en | en_ZA |
| dc.publisher | University of the Free State | en_ZA |
| dc.rights.holder | University of the Free State | en_ZA |
| dc.subject | DNA amplification fingerprinting (DAF) | en_ZA |
| dc.subject | Encephalartos | en_ZA |
| dc.subject | Genetic distances | en_ZA |
| dc.subject | Phylogenetic relationships | en_ZA |
| dc.subject | Random amplified polymorphic DNA (RAPD) | en_ZA |
| dc.subject | Stangeria eriopus. | en_ZA |
| dc.subject | Cycadaceae -- Classification -- Molecular aspects | en_ZA |
| dc.subject | Dissertation (M.Sc. (Botany))--University of the Free State, 2000 | en_ZA |
| dc.title | A molecular systematic study of the genus Encephalartos | en_ZA |
| dc.type | Dissertation | en_ZA |