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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.
71

Análise da conectividade entre populações de Carijoa riisei (Duchassaing e Michelotti) (Cnidaria: Octocorallia) na costa brasileira através de abordagens morfológica, molecular e reprodutiva

BARBOSA, Taciana Martins 31 August 2015 (has links)
Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-04-12T12:41:55Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese Taciana Martins Barbosa Biblioteca Central.pdf: 2266957 bytes, checksum: c72479b848ff65eb617cd5065338256f (MD5) / Made available in DSpace on 2016-04-12T12:41:55Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese Taciana Martins Barbosa Biblioteca Central.pdf: 2266957 bytes, checksum: c72479b848ff65eb617cd5065338256f (MD5) Previous issue date: 2015-08-31 / FACEPE / O octocoral Carijoa riisei é um cnidário colonial que possui ampla distribuição geográfica no Oceano Atlântico Sul, Caribe, Pacífico e Indo-Pacífico. Com intuito de conhecer a estrutura e a conectividade das populações da espécie, abordagens diferentes foram realizadas. Em pequena escala geográfica espacial (6-125 km) a partir de diferentes ambientes (recifes costeiros, naufrágios e estuários) da costa de Pernambuco (Brasil), análises do DNAmt, morfológicas e reprodutivas foram realizadas. Verificou-se que houve variação morfológica em 10 dos 11 caracteres morfológicos avaliados quando comparadas as localidades estudadas. No entanto, não há diferenciação genética entre as sete populações estudadas devido ao alto fluxo gênico, indicando que a espécie em Pernambuco consiste em uma população panmítica. Portanto, a alta variabilidade morfológica de C. riisei encontrada neste estudo é devido à plasticidade fenotípica em resposta às mudanças ambientais e não ao acúmulo de diferenças genéticas devido à interrupção do fluxo gênico entre as populações. Para análise em grande escala geográfica espacial (108-2781 km), o exame da conectividade genética por meio do DNAmt foi realizado em populações do Atlântico Sul/Brasil e comparado com resultados encontrados de outras regiões do Atlântico (Leste e Norte) e do mundo (Pacífico/Havaí e Indo-Pacífico). Estruturação genética foi observada em duas das seis populações estudadas no Atlântico Sul/Brasil. Contudo, foi verificado fluxo gênico suficiente para conectar todas as populações, tanto dentro do Atlântico Sul, como entre as populações desta região com as demais. O Atlântico Sul apresentou a maior diversidade genética entre todas as regiões do Atlântico estudadas. Quando a comparação é realizada entre as regiões geográficas do mundo, a maior diversidade genética foi encontrada no Indo-Pacífico e a menor no Atlântico Norte. De acordo com esses resultados e aliado com o que existe na literatura, encontra-se suporte à ideia de que C. riisei é nativa do Indo-Pacífico. A conectividade genética das populações em organismos sésseis é alcançada pela dispersão larval. Este estudo descreve pela primeira vez a embriogênese, desenvolvimento e assentamento larval de C. riisei. Foram recolhidas colônias na costa norte de São Paulo, Brasil e mantidos vivos em aquários. Através da observação direta, verificou-se que a liberação dos gametas predominantemente ocorreram entre 05h00-10h00. A fertilização é externa e os ovos fertilizados tem um diâmetro médio de 403 ± 6,0 μm, apresentando geralmente flutuabilidade positiva. As clivagens são superficiais, o primeiro ciclo de divisão ocorre perto de 3h30-5 h após a liberação dos gametas. A divisão citoplasmática é rápida (15-20 min), facilmente visível nas fases de 16 e 32 células. As larvas plânulas são formadas entre 27-36 h após a liberação dos gametas; podem nadar por toda a coluna dágua e atingir 1,8 mm de comprimento. As plânulas assentam entre 10-18 dias após a liberação dos gametas. O pólipo primário é translúcido, e os tentáculos emergem como oito pequenos botões arredondados. Portanto, a espécie tende a ter um potencial de dispersão de longa distância, que aliado ao nível considerável de variação morfológica (que favorece a adaptação da espécie em condições ecológicas heterogêneas) e a conectividade ocorrendo entre populações em pequena e grande escala geográfica espacial, auxiliam a compreender a ampla distribuição deste octocoral. / The octocoral Carijoa riisei is widely spread in the South Atlantic Ocean, Caribbean, Pacific and Indo-Pacific. Seeking to know the structure and connectivity of populations of the species, different approaches have been undertaken. In small spatial geographic scale (6-125 km) from different environments (coastal reefs, shipwrecks and estuaries) from the coast of Pernambuco (Brazil), analysis of mtDNA, morphological and reproductive were held. It was found that there is morphological variation in 10 of 11 morphological characters evaluated when compared the locations studied. However, there is no genetic differentiation among the populations studied due to high gene flow, indicating that the species in Pernambuco consists of a panmitic population. Therefore, the high morphological variability of C. riisei found in this study is due to phenotypic plasticity in response to environmental changes and not the accumulation of genetic differences due to the interruption of gene flow between populations. For analysis in large spatial geographic scale (108-2781 km), examination of genetic connectivity through mtDNA was held in South Atlantic/Brazil populations and compared with results from other regions of the Atlantic (East and North) and the world (Pacific/Hawaii and Indo-Pacific). Genetic structure was observed in two of the six studied populations in the South Atlantic/Brazil. However, it was found sufficient gene flow to connect all populations, both within the South Atlantic, as among populations of this region with others. The South Atlantic showed the highest genetic diversity among all regions of the Atlantic studied. When a comparison is performed among the geographic regions of the world, the greatest genetic diversity was found in the Indo-Pacific and the smallest in the North Atlantic. According to these results and allied with what exists in the literature, it supports the idea that C. riisei is native to the Indo-Pacific. Genetic connectivity of populations in sessile organisms is achieved by larval dispersal. This study describes for the first time embryogenesis, development and larval settlement of this octocoral. Colonies were collected on the north coast of São Paulo, Brazil and kept alive in aquariums. Through direct observation, it was found that spawns predominantly occurred in the morning between 05h00-10h00. The fertilization is external and fertilized eggs have an average diameter of 403 ± 6.0 μm, usually presenting positive buoyancy. The cleavages are superficial, the first division cycle occurs near 3h30-5 h after spawning. The cytoplasmic division is rapid (15-20 min), easily visible in stages 16 and 32 cells. The larvae planula are formed 27-36 h after spawning; can swim throughout the water column and reach a length of 1.8 mm. Planulae settle 10-18 days after spawning. The primary polyp is translucent, and the tentacles emerge as eight small round buttons. Therefore, the species tends to have a potential for long-distance dispersal, that coupled with the considerable level of morphological variation (that favors the adaptation of the species in heterogeneous ecological conditions) and connectivity between populations occurring in small and large spatial geographic scale assists to understand the wide distribution of this octocoral.
72

PopGen Fishbowl: A Free Online Simulation Model of Microevolutionary Processes

Jones, Thomas C., Laughlin, Thomas F. 01 February 2010 (has links)
Natural selection and other components of evolutionary theory are known to be particularly challenging concepts for students to understand. To help illustrate these concepts, we developed a simulation model of microevolutionary processes. The model features all the components of Hardy-Weinberg theory, with population size, selection, gene flow, nonrandom mating, and mutation all being demonstrated in the simulations. By using this freely available computer model, students can develop and test hypotheses with replicated virtual experiments. Because the model is an agent-based simulation, there is biologically realistic variability in the results. Students using the model see results both numerically and graphically and these are reinforced by an animation of the virtual fish in the simulated experiment.
73

The effects of landscape features on the distribution and genetic structure of forest duikers (Cephalophinae) in the tropical forest of Moukalaba, Gabon / ガボン、ムカラバの熱帯林におけるダイカー亜科(Cephalophinae)の分布と遺伝構造に与える景観の影響

Akomo, Okoue Etienne Francois 24 November 2015 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第19360号 / 理博第4122号 / 新制||理||1593(附属図書館) / 32374 / 新制||理||1593 / 京都大学大学院理学研究科生物科学専攻 / (主査)教授 中川 尚史, 教授 中務 真人, 教授 曽田 貞滋 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM
74

Spatial and Temporal Genetic Structure in Chloroplast and Allozyme Markers in Phacelia Dubia Implicate Genetic Drift

Levy, Foster, Neal, Christopher L. 01 January 1999 (has links)
For neutral genes, uniparental inheritance is expected to reduce effective population size relative to biparentally inherited genes. In finite populations, the ensuing genetic drift can cause stronger spatial and temporal differentiation. An intrapopulation polymorphism in chloroplast DNA was used to examine relative spatial and temporal population structure of chloroplast and allozyme markers in the annual plant Phacelia dubia. There was significant differentiation among populations at chloroplast markers but not for allozyme loci. A fine-scale analysis showed significant structure among sites within populations for chloroplast markers and local heterozygote deficiencies at allozyme loci. These spatial analyses suggest that gene flow via pollen exceeds that via seed. Temporal variation in chloroplast markers, assessed over a 10-year period, was evident in two of four populations, and allozyme loci were characterized by temporal variation in rare-allele frequencies. Population structure appeared to be related to the intensity and type of human disturbance influencing each population. Habitat destruction promoted isolation and enhanced differentiation, whereas mowing increased seed dispersal and reduced differentiation for chloroplast markers. At this time, genetic drift appears to be the primary force shaping chloroplast gene frequencies.
75

Families in the Sky: Investigating the Population Structure of Pinus longaeva

Decker, Samuel Arnold 11 April 2022 (has links)
In the Western United States, the Great Basin is a geographic feature that is home to a variety of unique species, including Great Basin bristlecone pine (Pinus longaeva, PILO). P. longaeva is well known for the age of some of the trees, some of which are over 4000 years old. In this study 17 microsatellite markers (simple sequence repeat, SSR) are identified and used to genotype a selection of 480 individuals spread across 24 PILO populations and 60 individuals divided equally between 2 outgroup species, Pinus aristata and Pinus flexilis. One population of PILO, HMW, shows more genetic similarity with P. aristata, and is included with outgroup species in the analysis. The population structure of PILO is examined and found to be weakly related to the geographic distance between populations. The population statistics Fst, Gst, Rst, Dest and an AMOVA analysis suggest that there is a substantial amount of admixture at the individual level, similar to some other species of pines. Phylogenetic trees computed using the neighbor-joining method based on the average population genetic distance and based on individual genetic distance support the population structure results and show further evidence that most of the species variation is concentrated at the individual level, rather than inside of or between species. It is possible that gene flow is still occurring, or that gene flow has occurred recently enough that the separated populations have not yet diverged from each other in a measurable way.
76

Population genetic analyses inform conservation of the endangered Clouded Apollo (Parnassius mnemosyne) butterfly in Sweden

Mrazek, Veronika January 2022 (has links)
The clouded apollo (Parnassius mnemosyne) is a palearctic butterfly with a wide distribution across Eurasia. In recent decades, however, the species has declined in many parts of its distribution range. In Sweden, both the distribution and populations size of the clouded apollo has decreased dramatically over the past two decades, mainly due to habitat loss resulting from changes in land use practices. Today, only three geographically isolated populations remain in Sweden, as well as one captive population. While previous studies have explored the population genetics of other clouded apollo populations across Eurasia, little is known about the genetics of the remaining populations in Sweden. Here we make use of whole genome resequencing data from clouded apollo individuals collected in each of the three natural populations as well as the captive population. We apply population genetic analyses and explore mitochondrial gene data when mapping to two different reference genome assemblies, to get a better understanding of the genetic structure and levels of genetic diversity of the populations in Sweden. Our results show that the clouded apollo populations in different geographic regions harbour similar but relatively low levels of genetic diversity. We also find significant genetic differentiation between the northernmost population and the populations in southern Sweden, as well as higher levels of inbreeding in this population. Our analysis of the mitochondrial CO1 gene coupled with previously available data, shows that the remaining clouded apollo populations in Sweden correspond to two distinct mitochondrial haplogroups characteristic of different regions of Eurasia. Together with our other results, this indicates a re-colonisation of Scandinavia via two different routes after the last glacial maximum. Finally, our analyses uncover sub-population substructure in one of the remaining populations in southern Sweden. Together our results provide a first overview of the populations genetics of the clouded apollo butterfly in Sweden and explore the genetic consequences of populations size declines and fragmentation in the region. These findings were communicated to local conservation authorities and used to inform conservation strategies to protect this endangered species in Sweden.
77

ASSISTED EVOLUTION AS A TOOL TO INCREASE CORAL THERMOTOLERANCE IN THE RED SEA

Barreto, Marcelle 12 1900 (has links)
The rise of atmospheric CO2 is a threat to many ecosystems, including coral reefs. Rising sea surface temperatures are known to interfere on coral health and cause extensive worldwide mortality. In the Red Sea, coral reefs are spread across 18 degrees of latitude, resulting in a temperature gradient with maximum monthly mean sea surface temperatures ranging from around 33 °C in the south to 27°C in the north. Such gradients can lead to adaptations to local conditions, with coral thermal performance expected to increase along temperature/latitude gradients. In this research, I used the corals Porites lobata and Platygyra daedalea collected in various locations in the Red Sea to resolve fine-scale populational differences in thermotolerance along the Red Sea, and assess if this variability can be explored for potential assisted gene flow projects (i.e. assisted migration and selective breeding) within the Red Sea region. In chapter two, a heat stress assay indicated that P. lobata colonies from the Southern Red Sea have a higher thermal bleaching threshold than conspecifics from Northern latitudes, highlighting their potential as source of temperature resilient colonies. In chapter three, a common garden experimental design showed that thermotolerance of southern P. lobata colonies is maintained when transplanted to a foreign environment. However, despite lack of bleaching in Southern colonies, mortality rates of approximately 20% suggested that other environmental constraints besides temperature might impact coral health and survival. In chapter four, purebred Arabian Gulf larvae generated by cross-breeding colonies of Platygyra daedalea collected along the Red Sea and the Arabian Gulf showed higher survival under heat stress. In addition, paternal survival index increased in crosses with fathers from warmer locations. These results combined indicate that assisted gene flow via translocation alone may have limited success due to a lack of local adaptations to environmental conditions other than temperature. Nonetheless, inter-populational breeding may overcome these limitations as they could generate offspring with both increased thermal tolerance and local adaptations.
78

AMONG-LOCUS HETEROGENEITY IN GENETIC DIVERSITY AND DIVERGENCE IN TWO PAIRS OF DUCK SPECIES (GENUS: ANAS)

Dhami, Kirandeep K. January 2012 (has links)
No description available.
79

Mechanisms facilitating and evolutionary consequences of gene flow in two crop-wild hybrid complexes: sunflower and rice

Reagon, Michael 05 January 2007 (has links)
No description available.
80

Rapid evolution in a crop-weed complex (<i>Raphanus</i> spp.)

Campbell, Lesley G. 16 January 2007 (has links)
No description available.

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