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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

Hipóteses filogenéticas de espécies sul americanas do gênero Lippia Spp. (Verbenacea) com base em sequências nucleotídicas

Sampaio, Fernanda 13 February 2009 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-03-23T19:08:09Z No. of bitstreams: 1 fernandasampaio.pdf: 1013409 bytes, checksum: a971117fc3bdd9c19272fe04cac30974 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-03-24T12:55:01Z (GMT) No. of bitstreams: 1 fernandasampaio.pdf: 1013409 bytes, checksum: a971117fc3bdd9c19272fe04cac30974 (MD5) / Made available in DSpace on 2017-03-24T12:55:01Z (GMT). No. of bitstreams: 1 fernandasampaio.pdf: 1013409 bytes, checksum: a971117fc3bdd9c19272fe04cac30974 (MD5) Previous issue date: 2009-02-13 / O gênero Lippia é um dos principais da família Verbenaceae e em sua maior parte está concentrado no Brasil, México, Paraguai e Argentina com poucas espécies endêmicas na África. O objetivo deste trabalho foi a construção de uma hipótese filogenética para 39 espécies do gênero Lippia ocorrentes no Brasil, Argentina, Bolívia, Paraguai e Uruguai com base em dados moleculares das regiões ITS, Waxy, TrnL-F e trnQ-rps16. As sequências foram amplificadas e purificadas para posterior seqüenciamento. As análises foram feitas utilizando-se Máxima Verossimilhança e Inferência Bayesiana. O presente trabalho revelou, pela primeira vez, aspectos filogenéticos de espécies do gênero Lippia com base em caracteres moleculares. De modo geral, as árvores filogenéticas baseadas nas diferentes regiões gênicas estudadas revelaram questões importantes como é o caso do monofiletismo da seção Goniostachyum. Outro ponto importante envolve a falta de resolução das seções Dipterocalix, Rhodolippia e Zapania. Dentre elas destaca-se a seção Zapania que constitui em vários aspectos estudados, a seção mais diversa. Embora o presente trabalho tenha mostrado aspectos inéditos com relação à organização filogenética de espécies e seções do gênero Lippia, a questão da especiação no gênero permanece em aberto. É possível que para resolver este problema sejam necessários estudos populacionais e filogeográficos, embasados por uma análise filogenética com maior número de genes e principalmente, envolvendo um maior número de espécies. / Lippia is one of the most important genus of the Verbenaceae family. It is mainly concentrated in Brazil, Mexico, Paraguay and Argentina with few endemic species in Africa. The present study was done in order to construct a phylogenetic hypothesis for 39 species of the genus Lippia from Brazil, Argentina, Bolivia, Paraguay and Uruguay based on molecular data of regions ITS, Waxy, TrnL-F and rps16-trnQ. The sequences were amplified and purified for subsequent sequencing. The phylogenetic analyses were done using the Maximum Likelihood and Bayesian Inference. It was possible to show for the first time, phylogenetic aspects of the genus Lippia based on molecular data. In general, the phylogenetic trees based on different gene regions revealed important points such as the monophyly of Goniostachyum section. Another important point involves the lack of resolution of the sections Dipterocalix, Rhodolippia and mainly Zapania which is the most diverse among them. Although this work has shown new aspects about the phylogenetic organization of sections and species of the genus Lippia, the speciation process of the genus remains an open question. To resolve this problem, additional studies using phylogeographic and population genetics approaches, based on a phylogenetic analysis with greater numbers of genes and mainly involving a great number of species should be necessary.
2

The phylogeography, biomass allocation and phenology of Salicornia tegetaria (S. Steffen, Mucina & G. Kadereit) Piirainen & G. Kadereit, an endemic salt marsh species in South Africa

Brown, Catherine January 2018 (has links)
Magister Scientiae (Biodiversity and Conservation Biology) - MSc (Biodiv & Cons Biol) / Salicornia tegetaria is an endemic salt marsh macrophyte that is widely distributed in estuaries along the South African coast. The aims of the study were to understand the phylogeography of the species, compare the biomass allocation in two regions and to determine phenological patterns of S. tegetaria between the warm and cool temperate biogeographical regions. The phylogeography of S. tegetaria was studied using the noncoding chloroplast DNA region rpS16 and nuclear rDNA ITS region. Five samples each were collected from eighteen estuaries stretching from Orange River in the Northern Cape to Mngazana Estuary in the Eastern Cape. Above- and belowground biomass was collected and physico-chemical conditions measured at Olifants, Berg and Langebaan Estuaries in the cool temperate, and Heuningnes, Nahoon and Kwelera Estuaries in the warm temperate biogeographical regions. The growth and flowering phenology of S. tegetaria in relation to environmental conditions was investigated in the cool temperate Langebaan Estuarine Embayment and compared to findings in the warm temperate, permanently open Kowie Estuary. The physico-chemical gradient found between the cool and warm temperate biogeographical regions may be useful to study climate change effects on plant species. The comparison of similar habitats in each region may provide insight into how different climate regimes may affect biomass allocation and phenology.
3

The phylogeography, biomass allocation and phenology of Salicornia tegetaria (S. Steffen, Mucina & G. Kadereit) Piirainen & G. Kadereit, an endemic salt marsh species in South Africa

Brown, Catherine Eileen January 2018 (has links)
Magister Scientiae (Biodiversity and Conservation Biology) - MSc (Biodiv & Cons Biol) / Salicornia tegetaria is an endemic salt marsh macrophyte that is widely distributed in estuaries along the South African coast. The aims of the study were to understand the phylogeography of the species, compare the biomass allocation in two regions and to determine phenological patterns of S. tegetaria between the warm and cool temperate biogeographical regions. The phylogeography of S. tegetaria was studied using the noncoding chloroplast DNA region rpS16 and nuclear rDNA ITS region. Five samples each were collected from eighteen estuaries stretching from Orange River in the Northern Cape to Mngazana Estuary in the Eastern Cape. Above- and belowground biomass was collected and physico-chemical conditions measured at Olifants, Berg and Langebaan Estuaries in the cool temperate, and Heuningnes, Nahoon and Kwelera Estuaries in the warm temperate biogeographical regions. The growth and flowering phenology of S. tegetaria in relation to environmental conditions was investigated in the cool temperate Langebaan Estuarine Embayment and compared to findings in the warm temperate, permanently open Kowie Estuary. The physico-chemical gradient found between the cool and warm temperate biogeographical regions may be useful to study climate change effects on plant species. The comparison of similar habitats in each region may provide insight into how different climate regimes may affect biomass allocation and phenology.
4

Coevolution of Ribosomes and The Translational Apparatus: The Structure and Function of Eukaryotic Ribosomal Protein uS7 from Yeast, Saccharomyces cerevisiae.

Ghosh, Arnab 25 June 2015 (has links)
No description available.
5

Disentangling the Reticulate History of Polyploids in <i>Silene </i>(<i>Caryophyllaceae</i>)

Popp, Magnus January 2004 (has links)
<p>DNA sequences from the <i>rps16</i> intron and the <i>psbE-petL</i> spacer from the chloroplast genome, the ribosomal nuclear ITS region, and introns from the low copy nuclear genes <i>RPA2</i>, <i>RPB2</i>, <i>RPD2a</i> and <i>RPD2b</i>, are in different combinations used to infer phylogenetic relationships in <i>Sileneae</i> (<i>Caryophyllaceae</i>). Used in concert, the biparentally inherited nuclear regions are useful to distinguish between paralogy due to allopolyploidy and single gene duplications, respectively, because the latter are not expected to give rise to repeated phylogenetic patterns in potentially unlinked sequence regions. In addition, the sequences resolve previously poorly known relationships in the tribe <i>Sileneae</i>. Several independent losses and incomplete concerted evolution are inferred between the two <i>RPD2</i> paralogues in a subgroup of <i>Silene</i>.</p><p>An allopolyploid origin is suggested for the tetraploid <i>S. aegaea</i>, with the maternal ancestor from the diploid <i>S. pentelica</i> lineage, and the paternal contributor from the diploid <i>S. sedoides</i> lineage.</p><p><i>Silene involucrata</i> originated as an allotetraploid with the diploid lineage of Arctic <i>S. uralensis</i> as cytoplasmic donor and the diploid Siberian/Northeast Asian <i>S. ajanensis</i> lineage as pollen donor. A subsequent allopolyploidization with the <i>S. ajanensis</i> lineage as pollen donor and the tetraploid <i>S. involucrata</i> lineage as cytoplasmic donor resulted in the hexaploid lineage of <i>S. sorensenis sensu lato</i>.</p><p>A monophyletic origin of the North American polyploids is rejected. One lineage consists of tetraploid <i>S. menziesii</i> and its diploid allies. A separate lineage leads to a clade consisting of both diploid and polyploid Arctic, European and Asian taxa in addition to the majority of the North American polyploids. The tetraploid <i>S. californica</i> and the hexaploid <i>S. hookeri</i> are derived from separate allopolyploidization events between these two lineages.</p>
6

Phylogenetic Studies in the Gentianales – Approaches at Different Taxonomic Levels

Backlund, Maria January 2005 (has links)
This thesis deals with phylogenetic relationships at different taxonomic levels. All the plants studied are or have been included in the order Gentianales, which comprises about 17 200 species. The phylogenies are based on parsimony analyses of nucleotide sequence data (DNA) from different regions in the chloroplast genome, but morphological characteristics have also been studied. Analyses of sequence data from the genes rbcL and ndhF provide the interfamilial structure of the order Gentianales, shown to comprise the families Apocynaceae (incl. Asclepiadaceae), Gelsemiaceae, Gentianaceae, Loganiaceae, and Rubiaceae. Exclusion of certain genera from the Loganiaceae is confirmed and their phylogenetic positions are clarified. Some of these genera remain within the Gentianales, while others belong to other orders. Exclusion of the tribe Buddlejeae from the Loganiaceae is confirmed, and a monophyletic group formed by Buddleja, Emorya, Gomphostigma, and Nicodemia is recognized and placed in the Lamiales. The Loganiaceae s.str. forms, after these exclusions, a strongly supported monophyletic group comprising 13 genera. The tribe Paederieae in the family Rubiaceae is analysed using sequence data from the regions rbcL gene, rps16 intron, and the regions trnT-F, and is shown to be paraphyletic. These results lead to a new circumscription of Paederieae comprising the genera Leptodermis, Paederia, Serissa, and Spermadictyon. The tribe Putorieae is reestablished with the single genus Plocama, including 34 species. Aitchisonia, Choulettia, Crocyllis, Gaillonia, Jaubertia, Pseudogaillonia, Pterogaillonia, and Putoria are reduced to synonyms of Plocama based on the molecular analyses and morphological studies. The Mediterranean species of the re-circumscribed Plocama, previously segregated as the genus Putoria, are revised. Two species, Plocama calabrica and P. brevifolia, are recognized, their synonymics are established, and seven lectotypes are selected.
7

Systematics in Sileneae (Caryophyllaceae) – Taxonomy and Phylogenetic patterns

Eggens, Frida January 2006 (has links)
The focus for the first part of the thesis is on the systematics of species belonging to Silene subgenus Silene. Phylogenetic relationships are inferred from DNA sequences from both the plastid (the rps16 intron) and the nuclear (ITS, intron of the RPB2 gene) genomes. Silene section Rigidulae is shown to be non-monophyletic in its previous circumscription, but instead consisting of six separate clades, each correlated to the geographical distribution of the included species. The taxonomic consequences for each clade are discussed. One of the clades is recognized as a new section and described as Silene sect. Arenosae sect. nov. The morphological descriptions of the species are formalized using a novel implementation of the Prometheus Description Model. Two proposals are included in the thesis, one to reject the name Silene polyphylla L., which is a senior synonym to S. portensis L. Silene linearis Decne. is proposed for conservation against the rarely used S. linearis Sweet. Silene antirrhina, a weedy American annual, is strongly supported as sister to the Hawaiian endemic species of Silene, suggesting an American origin for these. Two of the endemics have evolved woodiness after introduction to Hawaii. In the second part of the thesis we use four nuclear DNA regions, (introns from RPA2, RPB2, RPD2a, RPD2b), and the chloroplast psbE-petG spacer. A framework is developed to evaluate different phylogenetic explanations for conflicting gene trees, where divergence times are used to discriminate among inter- and intralineage processes. The incongruences observed regarding the relationships among the three major lineages of Heliosperma are best explained by homoploid hybridization. The pattern regarding the origin of Heliosperma itself is more complicated and is likely to include several reticulate events. Two lineages have probably been involved in the origin of Heliosperma, one leading to Viscaria and Atocion and the other to Eudianthe and/or Petrocoptis.
8

Disentangling the Reticulate History of Polyploids in Silene (Caryophyllaceae)

Popp, Magnus January 2004 (has links)
DNA sequences from the rps16 intron and the psbE-petL spacer from the chloroplast genome, the ribosomal nuclear ITS region, and introns from the low copy nuclear genes RPA2, RPB2, RPD2a and RPD2b, are in different combinations used to infer phylogenetic relationships in Sileneae (Caryophyllaceae). Used in concert, the biparentally inherited nuclear regions are useful to distinguish between paralogy due to allopolyploidy and single gene duplications, respectively, because the latter are not expected to give rise to repeated phylogenetic patterns in potentially unlinked sequence regions. In addition, the sequences resolve previously poorly known relationships in the tribe Sileneae. Several independent losses and incomplete concerted evolution are inferred between the two RPD2 paralogues in a subgroup of Silene. An allopolyploid origin is suggested for the tetraploid S. aegaea, with the maternal ancestor from the diploid S. pentelica lineage, and the paternal contributor from the diploid S. sedoides lineage. Silene involucrata originated as an allotetraploid with the diploid lineage of Arctic S. uralensis as cytoplasmic donor and the diploid Siberian/Northeast Asian S. ajanensis lineage as pollen donor. A subsequent allopolyploidization with the S. ajanensis lineage as pollen donor and the tetraploid S. involucrata lineage as cytoplasmic donor resulted in the hexaploid lineage of S. sorensenis sensu lato. A monophyletic origin of the North American polyploids is rejected. One lineage consists of tetraploid S. menziesii and its diploid allies. A separate lineage leads to a clade consisting of both diploid and polyploid Arctic, European and Asian taxa in addition to the majority of the North American polyploids. The tetraploid S. californica and the hexaploid S. hookeri are derived from separate allopolyploidization events between these two lineages.

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