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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

Revision of Juncaceae and Cyperaceae phylogeny based on cpDNA and nDNA

BROŽOVÁ, Viktorie January 2018 (has links)
The phylogeny of Juncaceae and Cyperaceae is still not fully understood. The morphology of this group is intricate and without clear homology, and molecular relationships are mostly studied on smaller parts of this large group of Monocots. Proper study is therefore needed. To obtain the most objective view on the phylogeny of these two families, we gathered data on 1174 taxa of rbcL, trnL-trnF, and ITS and analysed them by maximum parsimony, maximum likelihood, and Bayesian inference. Markers of cpDNA appeared much more useful than nDNA (ITS) due to the high rate of mutations in ITS which led to homoplasy and unsure alignment. By considering taxonomical impact of our study, the monophyly of the families and main inner topology of Juncaceae and several tribes of Cyperaceae (Abildgaardieae, Bisboeckelereae, Cariceae, Cypereae, Cryptangieae, Eleocharideae, Rhynchosporeae, Sclerieae, and Trilepideae) were confirmed; some changes in taxonomy were suggested (uniting of Chrysitricheae and Hypolytreae; division of Fuireneae; uniting of Cariceae, Dulicheae, Scirpeae, and Khaosokia caricoides into one tribe, or division of Scirpeae; and separation of Cladieae); changes in the classification of certain taxa were also suggested (the transfer of Distichia, Marsippospermim, Oxychloë, Patosia, and Rostkovia into Juncus, or division of Juncus into more genera; the transfer of Nemum spadiceum into Bulbostylis; Schoenoplectus corymbosus, S. gemmifer, S. hondoensis, and S. multisetus into the genus Schoenoplectiella; and Oreobolopsis into Trichophorum); and the identification of some taxa which possess special combinations of molecular and morphological features and should be studied further was made (Juncus capitatus, J. dregeanus, Bulbostylis juncoides, Crosslandia setifolia, Schoenoplectus litoralis, S. americanus, Cyperus iria, and Amphiscirpus nevadensis).
2

Estudos de sistemática molecular e de biogeografia histórica do bagre de água doce Pseudoplatystoma Bleeker, 1862 (Pimelodidae) na América do Sul

Costa, Luis Fernando Carvalho 26 March 2010 (has links)
Made available in DSpace on 2016-06-02T19:29:23Z (GMT). No. of bitstreams: 1 3030.pdf: 2014938 bytes, checksum: b6d8f7597811d1909e335b6facc588b7 (MD5) Previous issue date: 2010-03-26 / Universidade Federal de Minas Gerais / The catfishes of the Pseudoplatystoma genus are carnivore pimelodids, migratory and important for fisheries in all major river basins from South America. Only three species were recognized for the genus (P. corruscans, P. fasciatum and P. tigrinum), but a new revision raised to eight the number of species (P. fasciatum, P. punctifer, P. orinocoense, P. magdaleniatum, P. reticulatum, P. tigrinum, P. metaense and P. corruscans). Recently, Pseudoplatystoma was the subject of a molecular phylogeny study based on mitochondrial markers, where monophyletic clades where found for P. tigrinum, P. corruscans, P. reticulatum+P. punctifer+P. fasciatum and P. magdaleniatum. Despite these advances on the knowledge of the evolutionary history and systematics of the group, there are still questions to be answered. Thus, this study aimed a molecular phylogenetic analysis on Pseudoplatystoma to try to answer pendant questions about the systematics and taxonomy of the group, and propose a scenario for its diversification history in the geographic area of South America. In order to do this, we employed the mitochondrial Cytochrome b gene and introns from Rag1 and S7 genes, whose phylogenies were estimated by Maximum Likelihood using TREEFINDER software. Nodes were dated on BEAST software. It was shown that some Pseudoplatystoma species, resulting from the last revision of the genus, do not correspond to monophyletic groups or they were not significantly supported clades in all trees. The only monophyletic species in all markers were P. magdaleniatum and P. corruscans. Pseudoplatystoma orinocoense was a monophyletic lineage only on Cytochrome b. In light of these results, it is suggested that the old terminology P. fasciatum to be revalidated for the taxa here defined as P. fasciatum clade: P. punctifer (Amazon, Maranhão, Tocantins-Araguaia), P. reticulatum (Paraná-Paraguay) and P. fasciatum (Guyanas). Under the same rationale, P. tigrinum should be revalidated for Orinoco, given the paraphyletism of P. metaense. However, some cases of nonmonophyletic species in one or more markers may be due to incomplete lineage sorting, although this possibility needs to be investigated using other markers. The history of diversification of Pseudoplatystoma was the result of millions of years of evolution and and it was strongly influenced by the evolution of the South America geographical matrix. The biogeographic study allowed us to identify and date the important diversification events for the genus and relate them to the historical geomorphological and/or climate changes reported for South America, which would be the primary diversification causes for other freshwater fishes from the continent. / Os bagres do gênero Pseudoplatystoma são pimelodídeos carnívoros, migradores e de importância pesqueira em todas as grandes bacias hidrográficas da América do Sul. Apenas três espécies eram reconhecidas para o gênero (P. corruscans, P. fasciatum e P. tigrinum), mas uma nova revisão elevou para oito o número de espécies (P. fasciatum, P. punctifer, P. orinocoense, P. magdaleniatum, P. reticulatum, P. tigrinum, P. metaense e P. corruscans). Recentemente, Pseudoplatystoma foi alvo de um de estudo de filogenia molecular com marcadores mitocondriais, onde foram encontrados clados monofiléticos para P. tigrinum, P. corruscans, P. reticulatum+P. punctifer+P. fasciatum e P. magdaleniatum. Apesar desses avanços no conhecimento da história evolutiva e da sistemática do grupo, ainda restam questões a serem respondidas. Dessa forma, o presente estudo objetivou uma análise filogenética molecular em Pseudoplatystoma para tentar responder questões pendentes sobre a sistemática e taxonomia do grupo, bem como propor um cenário para sua história de diversificação no espaço geográfico da América do Sul. Para isso, foram empregados o gene mitocondrial do Citocromo b e íntrons dos genes Rag1 e S7, cujas filogenias foram estimadas por Máxima Verossimilhança no programa TREEFINDER. Os nós das filogenias foram datados no programa BEAST. Foi demonstrado que algumas espécies de Pseudoplatystoma, resultantes da última revisão do gênero, não correspondem a grupos monofiléticos ou não tiveram clados significativamente sustentados em todas as árvores. As únicas espécies monofiléticas em todos os marcadores foram P. magdaleniatum e P. corruscans. Pseudoplatystoma orinocoense só foi uma linhagem monofilética no Citocromo b. À luz desses resultados, sugere-se que a antiga terminologia P. fasciatum seja revalidada para os táxons do clado aqui definido como clado P. fasciatum: P. punctifer (Amazonas, Maranhão, Tocantins-Araguaia), P. reticulatum (Paraná-Paraguai) e P. fasciatum (Guianas). Sob a mesma racionalidade, P. tigrinum deveria ser revalidado para o Orinoco, dado o parafiletismo de P. metaense. Entretanto, alguns dos casos de espécies não-monofiléticas em um ou mais marcadores podem ser devidos à separação incompleta de linhagens, embora essa possibilidade necessite ser investigada com o uso de outros marcadores. A história da diversificação de Pseudoplatystoma foi resultado de milhões de anos de evolução e fortemente influenciada pela evolução da matriz geográfica Sul-Americana. O estudo biogeográfico nos permitiu identificar e datar os eventos de diversificação importantes para o gênero e relacioná-los às mudanças geomorfológicas e/ou climáticas históricas conhecidas para a América dos Sul, que seriam as causas primárias de diversificação de outros peixes de água doce do continente.
3

Fylogeneze vybraných rodů gekonů Mediteránu a přilehlých oblastí / Phylogeny of selected genera of geckos in the Mediterranean and adjacent regions

Červenka, Jan January 2014 (has links)
Phylogeny of selected genera of geckos in the Mediterranean and adjacent regions Jan Červenka Ph.D. thesis Abstract This Ph.D. thesis is composed of three published articles and one manuscript, and is focused on the phylogenetic relationships of selected species of geckos from the Mediterranean and surrounding areas. The group of geckos of interest shares the common characteristic of an absence of adhesive lamellas on their toes. Historically, it was assumed that these species were closely related. Molecular-phylogenetic approaches were used in order to reveal the phylogenetic relationships within this group, especially using the sequential data from mitochondrial genes. Morphological characteristics commonly used in lizards were studied in connection with the ecology of the group. This thesis provides the first more detailed view of the phylogeny of the studied species. The results show that the genus Cyrtopodion, previously considered as monophyletic, in fact is not monophyletic as the genera Bunopus and Agamura represent its inner groups. Mediodactylus, the subgenus of Cyrtopodion, forms monophylum but is not closely related to the other members of the genus and so was reclassified as the independent genus. The enigmatic and yet so far very poorly studied genus Carinatogecko was discovered to be the...
4

Genetická a morfologická variabilita skupiny \kur{Melampyrum nemorosum}

DRAHNÍK, Petr January 2016 (has links)
Melampyrum nemorosum agg. is very complicated group of hemiparasitic plants. According to the traditional concept, 15 species is distinguished. Recent molecular analyses show a need of critical taxonomic revision of group and a potential importance of ancient hybridization. Analysis of 3 regions of cpDNA (trnTUGU-trnLUAA, psbA-trnHGUG, rpl32-trnLUAG) and 2 regions of nuclear DNA (Agt1 and At103) reveals well supported lineage with limited geographical distribution. Morphology and genome size of genetically supported lineages were compared.
5

Genetická a morfologická variabilita skupiny \kur{Melampyrum nemorosum}

DRAHNÍK, Petr January 2016 (has links)
Melampyrum nemorosum agg. is very complicated group of hemiparasitic plants. According to the traditional concept, 15 species is distinguished. Recent molecular analyses show a need of critical taxonomic revision of group and a potential importance of ancient hybridization. Analysis of 3 regions of cpDNA (trnTUGU-trnLUAA, psbA-trnHGUG, rpl32-trnLUAG) and 2 regions of nuclear DNA (Agt1 and At103) reveals well supported lineage with limited geographical distribution. Morphology and genome size of genetically supported lineages were compared.
6

Etude de la variabilité génétique et de la phylogéographie de Santiria trimera (Burseraceae) - implications pour une conservation durable des forêts humides d’Afrique / Study of the genetic variability and the phylogeography of Santiria trimera (Burseraceae) – implications for a sustainable conservation of African rainforests.

Koffi, Kouamé Guillaume K. G. 22 November 2010 (has links)
La phylogéographie intègre l’information géographique et génétique pour inférer l’histoire démographique et les processus évolutifs des espèces. La présente étude recherche à travers les patrons de différenciation de l’ADN chloroplastique (ADNcp) au sein de Santiria trimera (Oliv.) H.J.LAM ex AUBR. [Emend. ONANA] la reconstitution d’une histoire des végétations des écosystèmes de forêts tropicales humides d’Afrique. Le modèle S. trimera est un arbre dioïque endémique des forêts humides d’Afrique dont les drupes sont dispersées par les primates et les oiseaux. Les formes morphologiques de ce modèle sont très variables et suscitent la délicate question de délimitation des espèces. Trois régions de l’ADNcp (l’intergène trnL-F, une portion du gène rbcL et l’intron rpl36-infA-rps8) ont été séquencées chez 377 individus issus de 42 populations de l’île de São Tomé, du Haut- et Bas-Guinéen pour étudier la phylogéographie. Des arbres phylogénétiques ont été réalisés sur des séquences d’un intron nucléaire du gène Phosphoenolpyruvate Carboxylase (72 individus) et sur les trois régions chloroplastiques. Une analyse morphométrique a été réalisée sur des données collectées sur des arbres en fruits. A l’aide de 10 locus microsatellites nucléaires, nous avons déterminé la structure génétique entre trois morphotypes sympatriques et analysé la structure génétique spatiale au sein de chaque groupe génétique. Le séquençage de l’ADNcp a mis en évidence des doubles pics sur les chromatogrammes de séquences. L’analyse des séquences clonées de produits PCR, la distribution des sites à doubles pics dans les séquences et dans les populations et les états ancestraux des positions à doubles pics nous ont permis d’interpréter les doubles pics comme résultant d’une co-amplification d’une copie chloroplastique et de copies nucléaires des régions séquencées. Les pics majeurs ont été considérés comme les nucléotides d’ADNcp d’origine maternelle et les pics mineurs ont été exclus de notre jeu de données. Les domaines phytogéographiques de São Tomé, du Haut- et Bas-Guinéen ne partagent aucun haplotype chloroplastique. Le Bas-Guinéen montre une plus grande diversité génétique. Les zones de distribution des haplotypes rares coïncident avec les refuges forestiers hypothétiques. L’analyse morphométrique et la phylogénie des séquences d’ADNcp suggèrent conjointement la reconnaissance de deux espèces bien différenciées. La structure génétique au sein d’une même population présumée suggère que les trois morphotypes en sympatrie dans les populations du Gabon constituent deux réservoirs génétiques différenciés sans individus hybrides. Selon le Concept Biologique de l’Espèce, S. trimera est probablement un mélange de deux espèces. On peut définir une espèce constituée d’individus avec des racines échasses et petites folioles coriaces (SRsl) et une seconde espèce constituée à la fois d’individus avec des racines échasses et de grandes folioles papyracées (SRll) et d’individus sans racine échasse avec de grandes folioles coriaces (NSR). Au vu de ces résultats, la classification taxonomique de S. trimera nécessite une révision. La confusion de ces deux espèces dans les forêts du Gabon explique une plus forte divergence de lignées chloroplastiques sympatriques par rapport aux lignées issues des régions biogéographiques isolées. L’un des deux haplotypes principaux de l’espèce à grandes folioles (SRll + NSR) est distribué dans le nord du Gabon et l’autre est distribué dans le sud. Au sein de l’espèce à petites folioles (SRsl), les zones d’endémisme de lignées chloroplastiques se situent dans l’Ouest du Cameroun qui est considéré comme une zone de fort endémisme et de forte diversité en espèces. Globalement, les patrons phylogéographiques mis en évidence entre lignées chloroplastiques de S. trimera sont compatibles avec les hypothèses biogéographiques basées sur les patrons de diversité et d’endémisme des espèces. / Phylogeography combines geographic and genetic information to infer demographic history and evolutionary processes. The present study of the spatial structure of chloroplast DNA (cpDNA) within Santiria trimera H.J.LAM ex AUBR. [Emend. ONANA], a primate- and bird-dispersed dioecious tree typical of African rainforests, provides insights into African vegetation history. This tree displays striking morphological variation which poses the problem of species delineation. Three regions of cpDNA (intergene trnL-F, a portion of rbcL gene and intron rpl36-infA-rps8) were sequenced in 377 individuals from 42 populations from São Tomé island and from Upper- and Lower-Guinean forests to study phylogeography. To study genetic divergence among morphotypes of S. trimera, phylogenies of a nuclear intron of Phosphoenolpyruvate Carboxylase from 72 individuals and concatenated sequences of the three cpDNA sequences were compared to morphological data from fruit-bearing trees. Using ten nuclear microsatellite markers, we defined the genetic structure among three sympatric morphotypes and analysed the spatial genetic structure within each genetic group. CpDNA sequences revealed double-peaks on sequence chromatograms. Sequences of cloned PCR products, the distribution of double peaks on sequences and in populations and ancestral nucleotides inferred from different taxa of the Burseraceae family enabled us to deduce that double peaks were due to the co-amplification of chloroplast and nuclear copies of the cpDNA region. Major peaks were considered as originating from maternal cpDNA. Subordinated peaks corresponding to the nuclear copies were excluded from our data set. The phytogeographic domains of São Tomé, Upper and Lower Guinea did not share any haplotype. Lower Guinea was the most diversified and the most divergent haplotypes were found in Gabonese forests. Endemism areas of haplotypes coincide with hypothetic forests refuges. Morphometric analyses and phylogenies cpDNA converge to delineating two well-differentiated species within S. trimera. Likewise, the genetic structure within one assumed population suggests that the three sympatric morphotypes constitute two genetically isolated populations without any hybrid. Following the Biological Species Concept, S. trimera is probably a mixture of two species in Lower Guinean forests. The first species is composed of all individuals with stilt roots and small leaflets (SRsl) and the second one is composed of both the morphotype with stilt roots, large and thin leaflets (SRll) and the morphotype without stilt roots with large and tough leaflets (NSR). In the view of our results, the taxonomical classification of S. trimera requires a revision. The confusion of both species in Gabonese forests explains that the highest divergence among chloroplast lineages was found in sympatric populations instead of among isolated biogeographic regions. One of the two major haplotypes of the second species (NSR + SRll) was distributed in the north of Gabon while the other haplotype was distributed in the south. Within the species with small leaflets (SRsl), areas of elevated haplotype endemism in West Cameroon coincided with hypothetic forest refuges. Overall, phylogeographic patterns within our model were in accordance with biogeographic hypotheses based on species endemism and diversity patterns.
7

Etude de la variabilité génétique et de la phylogéographie de Santiria trimera (Burseraceae): implications pour une conservation durable des forêts humides d'Afrique / Study of the genetic variability and the phylogeography of Santiria trimera (Burseraceae): implications for a sustainable conservation of African rainforests

Koffi, Kouamé Guillaume 22 November 2010 (has links)
La phylogéographie intègre l’information géographique et génétique pour inférer l’histoire démographique et les processus évolutifs des espèces. La présente étude recherche à travers les patrons de différenciation de l’ADN chloroplastique (ADNcp) au sein de Santiria trimera (Oliv.) H.J.LAM ex AUBR. [Emend. ONANA] la reconstitution d’une histoire des végétations des écosystèmes de forêts tropicales humides d’Afrique. Le modèle S. trimera est un arbre dioïque endémique des forêts humides d’Afrique dont les drupes sont dispersées par les primates et les oiseaux. Les formes morphologiques de ce modèle sont très variables et suscitent la délicate question de délimitation des espèces.<p>\ / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

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