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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Tracing History : Phylogenetic, Taxonomic, and Biogeographic Research in the Colchicum Family

Vinnersten, Annika January 2003 (has links)
<p>This thesis concerns the history and the intrafamilial delimitations of the plant family Colchicaceae. A phylogeny of 73 taxa representing all genera of Colchicaceae, except the monotypic <i>Kuntheria</i>, is presented. The molecular analysis based on three plastid regions—the <i>rps16</i> intron, the <i>atpB-rbcL</i> intergenic spacer, and the <i>trnL-F</i> region—reveal the intrafamilial classification to be in need of revision. The two tribes Iphigenieae and Uvularieae are demon-strated to be paraphyletic. The well-known genus <i>Colchicum</i> is shown to be nested within <i>Androcymbium</i>, <i>Onixotis</i> constitutes a grade between <i>Neodregea</i> and <i>Wurmbea</i>, and <i>Gloriosa</i> is intermixed with species of <i>Littonia</i>. Two new tribes are described, Burchardieae and Tripladenieae, and the two tribes Colchiceae and Uvularieae are emended, leaving four tribes in the family. At generic level new combinations are made in <i>Wurmbea</i> and <i>Gloriosa</i> in order to render them monophyletic. The genus <i>Androcymbium</i> is paraphyletic in relation to <i>Colchicum</i> and the latter genus is therefore expanded. An investigation of the distribution of colchicine within the expanded Colchicaceae is conducted to evaluate the potential of colchicine as a synapomorphy of the re-circumscribed family. The results demonstrate presence of colchicine in all genera previously not examined in Colchicaceae and in the genus <i>Burchardia</i>, earlier reported to lack colchicine. Hence, demonstrating colchicine to be a synapomorphy for the family. An attempt to date the phylogeny of the order Liliales together with a dispersal-vicariance (DIVA) analysis indicates that the split between Colchicaceae and Alstromeriaceae-Luzuriagaceae represents a vicariance event following the disintegration of the Australian-Antarctican-South American link, ~34 million years ago. Further, the DIVA analysis indicates that Colchicaceae originated in Australia, first reached Asia and North America, and later Africa, from where they expanded to Europe and also dispersed back to Australia. </p>
2

Tracing History : Phylogenetic, Taxonomic, and Biogeographic Research in the Colchicum Family

Vinnersten, Annika January 2003 (has links)
This thesis concerns the history and the intrafamilial delimitations of the plant family Colchicaceae. A phylogeny of 73 taxa representing all genera of Colchicaceae, except the monotypic Kuntheria, is presented. The molecular analysis based on three plastid regions—the rps16 intron, the atpB-rbcL intergenic spacer, and the trnL-F region—reveal the intrafamilial classification to be in need of revision. The two tribes Iphigenieae and Uvularieae are demon-strated to be paraphyletic. The well-known genus Colchicum is shown to be nested within Androcymbium, Onixotis constitutes a grade between Neodregea and Wurmbea, and Gloriosa is intermixed with species of Littonia. Two new tribes are described, Burchardieae and Tripladenieae, and the two tribes Colchiceae and Uvularieae are emended, leaving four tribes in the family. At generic level new combinations are made in Wurmbea and Gloriosa in order to render them monophyletic. The genus Androcymbium is paraphyletic in relation to Colchicum and the latter genus is therefore expanded. An investigation of the distribution of colchicine within the expanded Colchicaceae is conducted to evaluate the potential of colchicine as a synapomorphy of the re-circumscribed family. The results demonstrate presence of colchicine in all genera previously not examined in Colchicaceae and in the genus Burchardia, earlier reported to lack colchicine. Hence, demonstrating colchicine to be a synapomorphy for the family. An attempt to date the phylogeny of the order Liliales together with a dispersal-vicariance (DIVA) analysis indicates that the split between Colchicaceae and Alstromeriaceae-Luzuriagaceae represents a vicariance event following the disintegration of the Australian-Antarctican-South American link, ~34 million years ago. Further, the DIVA analysis indicates that Colchicaceae originated in Australia, first reached Asia and North America, and later Africa, from where they expanded to Europe and also dispersed back to Australia.
3

Filogenia y genética poblacional del género Androcymbium (Colchiceae)

Hoyo Leal, Alberto del 15 June 2006 (has links)
En este trabajo se ha estudiado el género Androcymbium (Colchicaceae) a dos niveles: macro- y micro- evolutivo. A nivel microevolutivo se ha obtenido que para las especies de Sudáfrica oriental la componente interpoblacional es muy importante para explicar la distribución de la variabilidad genética, igual que en Sudáfrica occidental. Para las especies de Namibia, la componente mas importante es la intrapoblacional, igual que en el norte de África. A nivel macroevolutivo se ha obtenido que el origen del género se sitúa en Sudáfrica occidental, datándose en 11,2&#61617;2 ma. Este género ha resultado ser parafilético, dada la aparición conjunta en un mismo clado de especies de Androcymbium y Colchicum, y las especies del norte de África derivan de un taxa de Namibia que llegó a la cuenca Mediterránea a principios del Plioceno gracias a la formación de un corredor árido entre las zonas áridas del suroeste y este de África. / In this study the genus Androcymbium (Colchicaceae) has been studied at two levels: macro- and micro- evolutive. At the microevolutive level it has been obtained that in the western south African species, the inter-populational component is very important to explain the distribution of the genetic variability, the same case like in western South Africa. In the Namibian species, the main component in the intra-populational, the same case as in north Africa. At the macroevolutive level it has obtained that the origin of the genus is located in western South Africa and it has been dated in 12.2&#61617;2 mya. This genus is paraphyletic because of the inclusion of some species of Colchicum within Androcymbium, and the origin of the northern Africa taxa are related with a Namibian taxa that colonized the Mediterranean basin at the beginning of Pliocene thanks to the formation of an arid corridor between the arid areas of south-western and eastern Africa.

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