• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 32
  • 11
  • 3
  • 3
  • 2
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 66
  • 19
  • 17
  • 17
  • 13
  • 13
  • 9
  • 9
  • 9
  • 8
  • 8
  • 8
  • 6
  • 6
  • 6
  • 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

Large-scale analysis of phylogenetic search behavior

Park, Hyun Jung 15 May 2009 (has links)
Phylogenetic analysis is used in all branches of biology by inferring evolutionary trees. Applications include designing more effective drugs, tracing the transmission of deadly viruses, and guiding conservation and biodiversity efforts. Most analyses rely on effective heuristics for obtaining accurate trees. However, relatively little work has been done to analyze quantitatively the behavior of phylogenetic heuristics in tree space. This is important, because a better understanding of local search behavior can facilitate the design of better heuristics, which ultimately leads to more accurate depictions of the true evolutionary relationships. In order to access and analyze the tree search space, we implement an effec- tive local search heuristic. Having an effective heuristic that can open the space is important, since no search heuristic in this field can effectively provide data collec- tion control. So we have implemented and estimated a search heuristic, Simple Local Search or SLS, that works reasonably well in the space. Our investigations led to several interesting observations about the behavior of a search heuristic and the tree search space. We studied the correlation of tree features of search path trees, where tree features refer to the parsimony score, the Robinson- Foulds distance and the homoplasy measure. Most importantly from the results, parsimony score was highly correlated with Robinson-Foulds distance only in trees that lie on the search path to a local optimum. We also note that the scores of neighborhoods along search paths improve together, as a local search progresses. Correlations of tree features of search path trees are particularly useful in char- acterizing and controlling a search path. This paper proposes one possible stopping criterion to maximize the tree search results while minimizing computational time tested on three biological datasets using the correlation between the parsimony score and the RF distance value of search path trees. Also, the observation that scores of a neighborhood on a search path improve together gives us a significant amount of flexibility in selecting the next pivot of a search without losing performance. Eventually, our long-term goal is developing an effective search heuristic that can deal with large scale tree space in reasonable time. Improved knowledge about the tree search space and the search heuristic can provide a reasonable starting point toward the goal.
2

Un modèle dynamique et parcimonieux du traitement automatisé de l'aspect dans les langues naturelles / A dynamic and parsimonious model for the processing of aspect in natural language

Munch, Damien 05 November 2013 (has links)
Dans cette thèse nous avons cherché et développé un modèle du traitement de l'aspect dans les langues naturelles. Notre objectif a été d'élaborer un modèle détaillé et explicatif qui montre la possibilité de traiter l'aspect sur un nombre choisi d’énoncés tout en suivant des contraintes fortes de parcimonie et de plausibilité cognitive. Nous avons réussi à mettre au point un modèle original dans sa réalisation, mais aussi dans ses résultats : des explications nouvelles sont données pour le traitement d'interprétations comme la répétition, la perfectivité ou l'inchoativité ; tout en dévoilant un phénomène original dit de "prédication". / The purpose of this work is to design and to implement a computational model for the processing of aspect in natural language.Our goal is to elaborate a detailed and explicative model of aspect. This model should be able to process aspect on a chosen number of sentences, while following strong constraints of parsimony and cognitive plausibility. We were successful in creating such a model, with both an original design and an extensive explanatory power. New explanations have been obtained for phenomena like repetition, perfectivity and inchoativity. We also propose a new mechanism based on the notion of “predication”.
3

Novel Mathematical Aspects of Phylogenetic Estimation

Fischer, Mareike January 2009 (has links)
In evolutionary biology, genetic sequences carry with them a trace of the underlying tree that describes their evolution from a common ancestral sequence. Inferring this underlying tree is challenging. We investigate some curious cases in which different methods like Maximum Parsimony, Maximum Likelihood and distance-based methods lead to different trees. Moreover, we state that in some cases, ancestral sequences can be more reliably reconstructed when some of the leaves of the tree are ignored - even if these leaves are close to the root. While all these findings show problems inherent to either the assumed model or the applied method, sometimes an inaccurate tree reconstruction is simply due to insufficient data. This is particularly problematic when a rapid divergence event occurred in the distant past. We analyze an idealized form of this problem and determine a tight lower bound on the growth rate for the sequence length required to resolve the tree (independent of any particular branch length). Finally, we investigate the problem of intermediates in the fossil record. The extent of ‘gaps’ (missing transitional stages) has been used to argue against gradual evolution from a common ancestor. We take an analytical approach and demonstrate why, under certain sampling conditions, we may not expect intermediates to be found.
4

Novel Mathematical Aspects of Phylogenetic Estimation

Fischer, Mareike January 2009 (has links)
In evolutionary biology, genetic sequences carry with them a trace of the underlying tree that describes their evolution from a common ancestral sequence. Inferring this underlying tree is challenging. We investigate some curious cases in which different methods like Maximum Parsimony, Maximum Likelihood and distance-based methods lead to different trees. Moreover, we state that in some cases, ancestral sequences can be more reliably reconstructed when some of the leaves of the tree are ignored - even if these leaves are close to the root. While all these findings show problems inherent to either the assumed model or the applied method, sometimes an inaccurate tree reconstruction is simply due to insufficient data. This is particularly problematic when a rapid divergence event occurred in the distant past. We analyze an idealized form of this problem and determine a tight lower bound on the growth rate for the sequence length required to resolve the tree (independent of any particular branch length). Finally, we investigate the problem of intermediates in the fossil record. The extent of ‘gaps’ (missing transitional stages) has been used to argue against gradual evolution from a common ancestor. We take an analytical approach and demonstrate why, under certain sampling conditions, we may not expect intermediates to be found.
5

Bayesian Variable Selection for Logistic Models Using Auxiliary Mixture Sampling

Tüchler, Regina January 2006 (has links) (PDF)
The paper presents an Markov Chain Monte Carlo algorithm for both variable and covariance selection in the context of logistic mixed effects models. This algorithm allows us to sample solely from standard densities, with no additional tuning being needed. We apply a stochastic search variable approach to select explanatory variables as well as to determine the structure of the random effects covariance matrix. For logistic mixed effects models prior determination of explanatory variables and random effects is no longer prerequisite since the definite structure is chosen in a data-driven manner in the course of the modeling procedure. As an illustration two real-data examples from finance and tourism studies are given. (author's abstract) / Series: Research Report Series / Department of Statistics and Mathematics
6

Filogenia de grupo Chlorocoris baseada em morfologia e evidência total, descrição de cinco novas espécies e sinopse de Chloropepla Stal, incluindo análise cladística e biogeográfica (Hemiptera: Heteroptera: Pentatomidae)

Greve, Caroline January 2010 (has links)
Apesar da monofilia de Pentatomidae ter sido amplamente demonstrada, as relações infrafamiliares precisam ser esclarecidas. Por exemplo, um dos maiores táxons da família, a subfamília Pentatominae, ainda não é reconhecido como um grupo monofilético. Para resolver estes problemas é necessário, além de conhecer a diversidade do grupo, realizar estudos cladísticos nos níveis genéricos e cladísticos. Na presente Tese são descritas cinco novas espécies do gênero Chloropepla (Pentatominae): C. paveli, C. stysi, Chloropepla sp. nov. 1, Chloropepla sp. nov. 2 e Chloropepla sp. nov. 3. As espécies são caracterizadas, principalmente, por atributos da genitália de machos e fêmeas. Uma chave ampliada para a identificação das espécies do gênero é fornecida. A distribuição setentrional do grupo é expandida da Venezuela para a Costa Rica. Uma sinopse de Chloropepla também é apresentada, com uma descrição ampliada do gênero e diagnose das espécies, ambas baseadas em análise de parcimônia das 12 espécies conhecidas. Esta análise cladística confirmou a monofilia do grupo, baseada no peritrema ostiolar longo e evanescente, hypandrium amplo com projeções dorsais atingindo o X segmento, parâmeros cilíndricos, dirigidos dorsalmente, conjuntiva membranosa reduzida, quase que inteiramente obscurecida pela phallotheca. A relação filogenética resultante entre as espécies de Chloropepla foi submetida à BPA com as subregiões e províncias da região Neotropical como terminais. Esta análise demonstrou uma relação próxima entre as áreas amazônicas e indicou uma natureza híbrida da sub-região chaquenha. Finalmente, a relação entre oito gêneros de Pentatominae é investigada: Arvelius, Chlorocoris, Chloropepla, Eludocoris, Fecelia, Loxa, Mayrinia e Rhyncholepta. Duas análises de parcimônia foram realizadas: uma baseada somente em caracteres morfológicos e outra baseada em morfologia e em sequências ribossomais (evidencia total). Um fragmento de rDNA mitocondrial 16S e dois de rDNA nuclear 28S foram sequenciados e analisados utilindo-se o método de optimização direta. As análises apresentaram diferentes relações entre os gêneros. Contudo, algumas relações se mantêm em ambos os cladogramas: Loxa + Mayrinia + Chlorocoris (Monochrocerus), Arvelius + E. humeralis + R. humeralis and Chlorochoris (Chlorocoris) + Fecelia + Chlorochoris (Arawacoris). Os resultados obtidos enfatizam a necessidade de estudos futures sobre o uso de dados moleculares em análises genéricas e específicas em Pentatominae. Além disto, as homologias também precisam ser melhor investigas e testadas, com base em estudos cladísticos, dentro de Pentatomidae, Pentatominae e tribos. / The monophyly of Pentatomidae was already highly confirmed. However, the infra-family relationships still need to be clarified. For example, one of the largest taxa of the family, the sub-family Pentatominae is not recognized as a monophyletic group. To solve these problems is necessary to know the diversity of the group as well as to perform cladistics studies at the level of genera and species. In this thesis, five new species of the genus Chloropepla (Pentatominae) are described: C. paveli, C. stysi, Chloropepla sp. nov. 1, Chloropepla sp. nov. 2 and Chloropepla sp. nov. 3. The species are mainly characterized by features of male and female genitalia. An extended key to identification of the species of the genus is provided. The northern distribution of the group is expanded from Venezuela to Costa Rica. A synopsis of Chloropepla is also presented, with an extended description of the genus and diagnosis for the species, both based in a parsimonious analysis of the 12 know species. This cladistics analysis confirmed the monophyly of the group, based on ostiolar ruga long and evanescent, wide hypandrium, with dorsal projections flanking the segment X, parameres cylindrical, dorsally directed, membranous conjunctiva reduced, almost entirely obscured by the phallotheca. The resultant phylogenetic relationship of Chloropepla species were submitted to a BPA with the sub-regions and provinces of Neotropical region as terminals. This analysis showed a near relation among the Amazonian areas and indicated a hybrid nature of the Chacoan subregion. Finally, the relationship of eight Pentatominae genera is investigated: Arvelius, Chlorocoris, Chloropepla, Eludocoris, Fecelia, Loxa, Mayrinia and Rhyncholepta. Two parsimony analyses were performed: one based solely on morphological characters and other based on morphological plus ribosomal DNA sequences (total evidence). One fragment of 16S mitochondrial and two of 28S nuclear rDNA were sequenced and analyzed using the direct optimization method. The results of both analysis differed in the relationships of the genera. However, some relations are recovered in both cladograms: Loxa + Mayrinia + Chlorocoris (Monochrocerus), Arvelius + E. humeralis + R. humeralis and Chlorochoris (Chlorocoris) + Fecelia + Chlorochoris (Arawacoris). The results here obtained emphasize the necessity of further studies on the use of molecular data in analyses on genera and species levels in Pentatominae. Besides, the homologies also need to be better investigated and tested within Pentatomidae, Pentatominae and tribes levels, based on cladistics studies.
7

Filogenia de grupo Chlorocoris baseada em morfologia e evidência total, descrição de cinco novas espécies e sinopse de Chloropepla Stal, incluindo análise cladística e biogeográfica (Hemiptera: Heteroptera: Pentatomidae)

Greve, Caroline January 2010 (has links)
Apesar da monofilia de Pentatomidae ter sido amplamente demonstrada, as relações infrafamiliares precisam ser esclarecidas. Por exemplo, um dos maiores táxons da família, a subfamília Pentatominae, ainda não é reconhecido como um grupo monofilético. Para resolver estes problemas é necessário, além de conhecer a diversidade do grupo, realizar estudos cladísticos nos níveis genéricos e cladísticos. Na presente Tese são descritas cinco novas espécies do gênero Chloropepla (Pentatominae): C. paveli, C. stysi, Chloropepla sp. nov. 1, Chloropepla sp. nov. 2 e Chloropepla sp. nov. 3. As espécies são caracterizadas, principalmente, por atributos da genitália de machos e fêmeas. Uma chave ampliada para a identificação das espécies do gênero é fornecida. A distribuição setentrional do grupo é expandida da Venezuela para a Costa Rica. Uma sinopse de Chloropepla também é apresentada, com uma descrição ampliada do gênero e diagnose das espécies, ambas baseadas em análise de parcimônia das 12 espécies conhecidas. Esta análise cladística confirmou a monofilia do grupo, baseada no peritrema ostiolar longo e evanescente, hypandrium amplo com projeções dorsais atingindo o X segmento, parâmeros cilíndricos, dirigidos dorsalmente, conjuntiva membranosa reduzida, quase que inteiramente obscurecida pela phallotheca. A relação filogenética resultante entre as espécies de Chloropepla foi submetida à BPA com as subregiões e províncias da região Neotropical como terminais. Esta análise demonstrou uma relação próxima entre as áreas amazônicas e indicou uma natureza híbrida da sub-região chaquenha. Finalmente, a relação entre oito gêneros de Pentatominae é investigada: Arvelius, Chlorocoris, Chloropepla, Eludocoris, Fecelia, Loxa, Mayrinia e Rhyncholepta. Duas análises de parcimônia foram realizadas: uma baseada somente em caracteres morfológicos e outra baseada em morfologia e em sequências ribossomais (evidencia total). Um fragmento de rDNA mitocondrial 16S e dois de rDNA nuclear 28S foram sequenciados e analisados utilindo-se o método de optimização direta. As análises apresentaram diferentes relações entre os gêneros. Contudo, algumas relações se mantêm em ambos os cladogramas: Loxa + Mayrinia + Chlorocoris (Monochrocerus), Arvelius + E. humeralis + R. humeralis and Chlorochoris (Chlorocoris) + Fecelia + Chlorochoris (Arawacoris). Os resultados obtidos enfatizam a necessidade de estudos futures sobre o uso de dados moleculares em análises genéricas e específicas em Pentatominae. Além disto, as homologias também precisam ser melhor investigas e testadas, com base em estudos cladísticos, dentro de Pentatomidae, Pentatominae e tribos. / The monophyly of Pentatomidae was already highly confirmed. However, the infra-family relationships still need to be clarified. For example, one of the largest taxa of the family, the sub-family Pentatominae is not recognized as a monophyletic group. To solve these problems is necessary to know the diversity of the group as well as to perform cladistics studies at the level of genera and species. In this thesis, five new species of the genus Chloropepla (Pentatominae) are described: C. paveli, C. stysi, Chloropepla sp. nov. 1, Chloropepla sp. nov. 2 and Chloropepla sp. nov. 3. The species are mainly characterized by features of male and female genitalia. An extended key to identification of the species of the genus is provided. The northern distribution of the group is expanded from Venezuela to Costa Rica. A synopsis of Chloropepla is also presented, with an extended description of the genus and diagnosis for the species, both based in a parsimonious analysis of the 12 know species. This cladistics analysis confirmed the monophyly of the group, based on ostiolar ruga long and evanescent, wide hypandrium, with dorsal projections flanking the segment X, parameres cylindrical, dorsally directed, membranous conjunctiva reduced, almost entirely obscured by the phallotheca. The resultant phylogenetic relationship of Chloropepla species were submitted to a BPA with the sub-regions and provinces of Neotropical region as terminals. This analysis showed a near relation among the Amazonian areas and indicated a hybrid nature of the Chacoan subregion. Finally, the relationship of eight Pentatominae genera is investigated: Arvelius, Chlorocoris, Chloropepla, Eludocoris, Fecelia, Loxa, Mayrinia and Rhyncholepta. Two parsimony analyses were performed: one based solely on morphological characters and other based on morphological plus ribosomal DNA sequences (total evidence). One fragment of 16S mitochondrial and two of 28S nuclear rDNA were sequenced and analyzed using the direct optimization method. The results of both analysis differed in the relationships of the genera. However, some relations are recovered in both cladograms: Loxa + Mayrinia + Chlorocoris (Monochrocerus), Arvelius + E. humeralis + R. humeralis and Chlorochoris (Chlorocoris) + Fecelia + Chlorochoris (Arawacoris). The results here obtained emphasize the necessity of further studies on the use of molecular data in analyses on genera and species levels in Pentatominae. Besides, the homologies also need to be better investigated and tested within Pentatomidae, Pentatominae and tribes levels, based on cladistics studies.
8

Análise filogenética de Mydinae (Insecta, Diptera, Mydidae) com base em caracteres morfológicos e moleculares / Phylogenetic analysis of Mydinae (Insecta, Diptera, Mydidae) based on morphological and molecular characters

Julia Calhau Almeida 04 April 2013 (has links)
A subfamília Mydinae (Insecta, Diptera, Mydidae) ocorre somente nas Américas e é composta por 12 gêneros e 84 espécies, sendo a grande maioria das espécies de Mydidae pertencentes a essa subfamília. Mydinae é atualmente dividida em quatro tribos: Dolichogastrini, Mydini, Phylomydini e Messiasiini. A monofilia da subfamília, assim como de suas tribos e gêneros, ainda não havia sido testada por análises filogenéticas, o que justifica os objetivos deste trabalho, que são: 1)testar a monofilia da subfamília Mydinae; 2)verificar o relacionamento filogenético dos Mydinae com outras subfamílias de Mydidae; 3)testar a monofilia das tribos, subtribos e gêneros de Mydinae, assim como a monofilia dos grupos de espécies do gênero Mydas; 4)propor uma nova classificação para a subfamília, baseada nos resultados filogenéticos. A partir de dados da morfologia externa de adultos, e também de sequência de DNA do gene COI, dois métodos de análise foram empregados: análises de parcimônia, com pesagem igual dos caracteres, e análises probabilísticas bayesianas. Para cada um dos métodos, foram analisados os dados morfológicos e moleculares separadamente, e também em conjunto. A monofilia de Mydinae, conforme delimitada na classificação vigente, não é corroborada no presente trabalho, em nenhuma das análises. Nas duas análises com dados morfológicos, e na análise bayesiana com dados morfológicos e moleculares, foi recuperado um clado formado por todos os Mydinae (exceto Messiasia wilcoxi) + Paramydas (\'Apiophorinae\'). Dentre as tribos de Mydinae, não foi recuperada a monifilia de Messiassiini e Mydini. Já os gêneros Ceriomydas, Stratiomydas, Phyllomydas e Protomydas foram reconhecidos como mofiléticos. Já os gêneros Baliomydas, Gauromydas, Messiasia e Mydas, não formaram grupos monofiléticos em nenhuma das análises. Neste trabalho, puderam ser testadas as monofilias de quatro dos cinco grupos de espécies de Mydas: clavatus, fulvifrons, interruptus e xanthopterus, sendo o grupo hardyi monotípico. Apenas o grupo interruptus foi recuperado como monofilético, embora seja reconhecido aqui que os caracteres de coloração tradicionalmente utilizados para a separação dos grupos não foram utilizados. A subfamília Apiophorinae, com amostragem de quatro espécies, não foi recuperada como monofilética, com o gênero Eumydas agrupando-se aos Rhopaliinae. A classificação de Mydinae é aqui revisada, porém devido à incerteza razoável quanto ao relacionamento entre alguns grupos, alguns táxons da classificação tradicional foram mantidos, apesar de não serem monofiléticos / The Mydinae (Insecta, Diptera, Mydidae) occur only in the Americas and comprise 12 genera and 84 species, of which the vast majority of mydids occurring in Brazil belonging to this subfamily. Mydinae is currently divided into four tribes: Dolichogastrini, Messiasiini, Mydini and Phylomydini. The monophyly of the subfamily, as well as the monophyly of their tribes and genera, had not yet been tested by phylogenetic analysis. Concerning this fact, the objectives of this work are: 1) test the monophyly of the subfamily Mydinae, 2) check the phylogenetic relationship between Mydinae and other subfamilies of Mydidae, 3) test the monophyly of the tribes, subtribes and genera of Mydinae, as well as the monophyly of the species-groups of the genus Mydas; 4) propose a new classification of the subfamily based on phylogenetic results. The data from the external morphology of adults, and also DNA sequence of the COI gene, two methods of analysis were used: parsimony analysis with equal weighting of characters, and Bayesian probabilistic analysis. For each method, morphological and molecular data were analyzed separately and also in combination. The monophyly of Mydinae, as defined in the current classification, is not borne out in the present study. In both analyzes with morphological data, and Bayesian analysis with morphological and molecular data, a clade formed by all Mydinae (except Messiasia wilcoxi) + Paramydas (\'Apiophorinae\') was recovered. Among the tribes of Mydinae, the monophylies of Messiassiini and Mydini were not recovered. The genera Ceriomydas, Stratiomydas, Phyllomydas and Protomydas are recognized as natural groups. In the other hand, the genera Baliomydas, Gauromydas, Messiasia and Mydas did not form monophyletic groups in any of the conducted analyzes. Concerning the Mydas species-groups, only the interruptus group was recovered as monophyletic, although it is recognized here that color based characters traditionally used for separating the groups were not used in the present work. The subfamily Apiophorinae, with four species sampled, was not recovered as monophyletic, with genus Eumydas grouping to Rhopaliinae. The classification of Mydinae is reviewed here, but due to reasonable uncertainty as to the relationships between some groups, some taxa of the traditional classification were kept, although not recognized as monophyletic
9

Filogenia de grupo Chlorocoris baseada em morfologia e evidência total, descrição de cinco novas espécies e sinopse de Chloropepla Stal, incluindo análise cladística e biogeográfica (Hemiptera: Heteroptera: Pentatomidae)

Greve, Caroline January 2010 (has links)
Apesar da monofilia de Pentatomidae ter sido amplamente demonstrada, as relações infrafamiliares precisam ser esclarecidas. Por exemplo, um dos maiores táxons da família, a subfamília Pentatominae, ainda não é reconhecido como um grupo monofilético. Para resolver estes problemas é necessário, além de conhecer a diversidade do grupo, realizar estudos cladísticos nos níveis genéricos e cladísticos. Na presente Tese são descritas cinco novas espécies do gênero Chloropepla (Pentatominae): C. paveli, C. stysi, Chloropepla sp. nov. 1, Chloropepla sp. nov. 2 e Chloropepla sp. nov. 3. As espécies são caracterizadas, principalmente, por atributos da genitália de machos e fêmeas. Uma chave ampliada para a identificação das espécies do gênero é fornecida. A distribuição setentrional do grupo é expandida da Venezuela para a Costa Rica. Uma sinopse de Chloropepla também é apresentada, com uma descrição ampliada do gênero e diagnose das espécies, ambas baseadas em análise de parcimônia das 12 espécies conhecidas. Esta análise cladística confirmou a monofilia do grupo, baseada no peritrema ostiolar longo e evanescente, hypandrium amplo com projeções dorsais atingindo o X segmento, parâmeros cilíndricos, dirigidos dorsalmente, conjuntiva membranosa reduzida, quase que inteiramente obscurecida pela phallotheca. A relação filogenética resultante entre as espécies de Chloropepla foi submetida à BPA com as subregiões e províncias da região Neotropical como terminais. Esta análise demonstrou uma relação próxima entre as áreas amazônicas e indicou uma natureza híbrida da sub-região chaquenha. Finalmente, a relação entre oito gêneros de Pentatominae é investigada: Arvelius, Chlorocoris, Chloropepla, Eludocoris, Fecelia, Loxa, Mayrinia e Rhyncholepta. Duas análises de parcimônia foram realizadas: uma baseada somente em caracteres morfológicos e outra baseada em morfologia e em sequências ribossomais (evidencia total). Um fragmento de rDNA mitocondrial 16S e dois de rDNA nuclear 28S foram sequenciados e analisados utilindo-se o método de optimização direta. As análises apresentaram diferentes relações entre os gêneros. Contudo, algumas relações se mantêm em ambos os cladogramas: Loxa + Mayrinia + Chlorocoris (Monochrocerus), Arvelius + E. humeralis + R. humeralis and Chlorochoris (Chlorocoris) + Fecelia + Chlorochoris (Arawacoris). Os resultados obtidos enfatizam a necessidade de estudos futures sobre o uso de dados moleculares em análises genéricas e específicas em Pentatominae. Além disto, as homologias também precisam ser melhor investigas e testadas, com base em estudos cladísticos, dentro de Pentatomidae, Pentatominae e tribos. / The monophyly of Pentatomidae was already highly confirmed. However, the infra-family relationships still need to be clarified. For example, one of the largest taxa of the family, the sub-family Pentatominae is not recognized as a monophyletic group. To solve these problems is necessary to know the diversity of the group as well as to perform cladistics studies at the level of genera and species. In this thesis, five new species of the genus Chloropepla (Pentatominae) are described: C. paveli, C. stysi, Chloropepla sp. nov. 1, Chloropepla sp. nov. 2 and Chloropepla sp. nov. 3. The species are mainly characterized by features of male and female genitalia. An extended key to identification of the species of the genus is provided. The northern distribution of the group is expanded from Venezuela to Costa Rica. A synopsis of Chloropepla is also presented, with an extended description of the genus and diagnosis for the species, both based in a parsimonious analysis of the 12 know species. This cladistics analysis confirmed the monophyly of the group, based on ostiolar ruga long and evanescent, wide hypandrium, with dorsal projections flanking the segment X, parameres cylindrical, dorsally directed, membranous conjunctiva reduced, almost entirely obscured by the phallotheca. The resultant phylogenetic relationship of Chloropepla species were submitted to a BPA with the sub-regions and provinces of Neotropical region as terminals. This analysis showed a near relation among the Amazonian areas and indicated a hybrid nature of the Chacoan subregion. Finally, the relationship of eight Pentatominae genera is investigated: Arvelius, Chlorocoris, Chloropepla, Eludocoris, Fecelia, Loxa, Mayrinia and Rhyncholepta. Two parsimony analyses were performed: one based solely on morphological characters and other based on morphological plus ribosomal DNA sequences (total evidence). One fragment of 16S mitochondrial and two of 28S nuclear rDNA were sequenced and analyzed using the direct optimization method. The results of both analysis differed in the relationships of the genera. However, some relations are recovered in both cladograms: Loxa + Mayrinia + Chlorocoris (Monochrocerus), Arvelius + E. humeralis + R. humeralis and Chlorochoris (Chlorocoris) + Fecelia + Chlorochoris (Arawacoris). The results here obtained emphasize the necessity of further studies on the use of molecular data in analyses on genera and species levels in Pentatominae. Besides, the homologies also need to be better investigated and tested within Pentatomidae, Pentatominae and tribes levels, based on cladistics studies.
10

Phylogenetic relationship of forest spiny pocket mice (Genus Heteromys) inferred from mitochondrial and nuclear markers with implications for species boundaries

Gonzalez, Malinda Wallentine 22 March 2005 (has links)
I constructed a best estimate phylogeny based on congruence of multiple data sources. In recent years molecular data has been used both to construct phylogenies of taxonomic groups and to aid in the delimitation of new species. I generated and analyzed sequence data for forest spiny pocket mice (Genus Heteromys) for the mitochondrial gene cyt b (1143 bp) and two nuclear gene segments MYH2 (252 bp) and EN2 (189 bp). I used maximum parsimony and Bayesian analyses to infer relationships among species and to provide a framework for using a species delimitation method to investigate the possibility of multiple species within the widespread Heteromys desmarestianus. I found several well-supported lineages within the H.desmarestianus complex, including H. goldmani and H. oresterus. Incorporating karyotype and allozyme data from earlier studies, I found sufficient supporting evidence to justify maintaining H. goldmani and H. oresterus as species as well as identifying four lineages as candidate species. I present a revised taxonomic arrangement within the genus; the subgenus Heteromys should be divided into three species groups: anomalus (H. anomalus and H. australis), gaumeri (H. gaumeri), and desmarestianus (H. desmarestianus, H. goldmani, H. oresterus, and the four candidate species).

Page generated in 0.0791 seconds