Molecular and morphological phylogenetic analyses of Euphorbia L. (Euphorbiaceae) with an emphasis on Southern African representatives

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dc.contributor.advisorHedderson, Terry Aen_ZA
dc.contributor.advisorBruyns, Peter Ven_ZA
dc.contributor.authorMapaya, Ruvimbo Jessyen_ZA
dc.date.accessioned2014-08-13T14:05:08Z
dc.date.available2014-08-13T14:05:08Z
dc.date.issued2003en_ZA
dc.descriptionBibliography: leaves 106-120.en_ZA
dc.description.abstractThe genus Euphorbia is morphologically diverse and nearly cosmopolitan. Both succulent and non-succulent species are found within the genus. Succulent species are found in most arid and semi-arid areas of the world, but show their greatest concentration and diversity of form in Southern Africa especially the Cape Floristic Region. The monophyly and phylogenetic relationships of the genus Euphorbia were investigated based on morphology and on sequences of the nuclear ribosomal internal transcribed spacer (ITS) and chloroplast psbA-trnH intergenic spacer. Fifty-one species of Euphorbia and four outgroups from Monadenium and Ciutia were sampled. Matrices were analysed using parsimony and maximum likelihood methods. Separate analyses of data partitions resulted in largely non-conflicting topologies; therefore the data sets were combined. The results showed that the genus Euphorbia is paraphyletic and four monophyletic groups with a number of putative synapomorphies defining each clade were strongly supported in most analyses. The Cape succulents fall into two well-supported clades. The results thus provided evidence for Cape radiations. Most analyses indicated that one of the Cape groups is sister to a group consisting of species mostly from Southern Africa (excludingthe Cape Region). Increased taxon sampling is however needed to clarify relationships within the monophyletic groups. Morphological characters recovered broad groups within Euphorbia. Due to inadequate sampling in some sections, modifications in the present classification of Euphorbia are not suggested. The total evidence tree was used to explore morphological character evolution through character state optimisations. The presence of root tubers was homoplasious and this character state is hypothesized to have arisen at least five times under current sampling. Cylindrical stems, conspicuous leaves and absence of leaf spines were some of the pleisiomorphic states observed in some sampled members of the genus Euphorbia. Although the results obtained in the CUlTent study are preliminary, they have created further challenges for future studies of phylogenetic relationships and morphological character evolution in the genus Euphorbia.en_ZA
dc.identifier.apacitationMapaya, R. J. (2003). <i>Molecular and morphological phylogenetic analyses of Euphorbia L. (Euphorbiaceae) with an emphasis on Southern African representatives</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Biological Sciences. Retrieved from http://hdl.handle.net/11427/6131en_ZA
dc.identifier.chicagocitationMapaya, Ruvimbo Jessy. <i>"Molecular and morphological phylogenetic analyses of Euphorbia L. (Euphorbiaceae) with an emphasis on Southern African representatives."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Biological Sciences, 2003. http://hdl.handle.net/11427/6131en_ZA
dc.identifier.citationMapaya, R. 2003. Molecular and morphological phylogenetic analyses of Euphorbia L. (Euphorbiaceae) with an emphasis on Southern African representatives. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Mapaya, Ruvimbo Jessy AB - The genus Euphorbia is morphologically diverse and nearly cosmopolitan. Both succulent and non-succulent species are found within the genus. Succulent species are found in most arid and semi-arid areas of the world, but show their greatest concentration and diversity of form in Southern Africa especially the Cape Floristic Region. The monophyly and phylogenetic relationships of the genus Euphorbia were investigated based on morphology and on sequences of the nuclear ribosomal internal transcribed spacer (ITS) and chloroplast psbA-trnH intergenic spacer. Fifty-one species of Euphorbia and four outgroups from Monadenium and Ciutia were sampled. Matrices were analysed using parsimony and maximum likelihood methods. Separate analyses of data partitions resulted in largely non-conflicting topologies; therefore the data sets were combined. The results showed that the genus Euphorbia is paraphyletic and four monophyletic groups with a number of putative synapomorphies defining each clade were strongly supported in most analyses. The Cape succulents fall into two well-supported clades. The results thus provided evidence for Cape radiations. Most analyses indicated that one of the Cape groups is sister to a group consisting of species mostly from Southern Africa (excludingthe Cape Region). Increased taxon sampling is however needed to clarify relationships within the monophyletic groups. Morphological characters recovered broad groups within Euphorbia. Due to inadequate sampling in some sections, modifications in the present classification of Euphorbia are not suggested. The total evidence tree was used to explore morphological character evolution through character state optimisations. The presence of root tubers was homoplasious and this character state is hypothesized to have arisen at least five times under current sampling. Cylindrical stems, conspicuous leaves and absence of leaf spines were some of the pleisiomorphic states observed in some sampled members of the genus Euphorbia. Although the results obtained in the CUlTent study are preliminary, they have created further challenges for future studies of phylogenetic relationships and morphological character evolution in the genus Euphorbia. DA - 2003 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2003 T1 - Molecular and morphological phylogenetic analyses of Euphorbia L. (Euphorbiaceae) with an emphasis on Southern African representatives TI - Molecular and morphological phylogenetic analyses of Euphorbia L. (Euphorbiaceae) with an emphasis on Southern African representatives UR - http://hdl.handle.net/11427/6131 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/6131
dc.identifier.vancouvercitationMapaya RJ. Molecular and morphological phylogenetic analyses of Euphorbia L. (Euphorbiaceae) with an emphasis on Southern African representatives. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Biological Sciences, 2003 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/6131en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Biological Sciencesen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherSystematics and Biodiversity Sciencesen_ZA
dc.titleMolecular and morphological phylogenetic analyses of Euphorbia L. (Euphorbiaceae) with an emphasis on Southern African representativesen_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMScen_ZA
uct.type.filetypeText
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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