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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.
361

Viabilidade genética de restaurações florestais : diversidade e estrutura genética em Myroxylon peruiferum L.f. / Genetic feasibility of forest restorations : genetic diversity and structure in Myroxylon peruiferum L.f.

Schwarcz, Kaiser Dias, 1982- 26 August 2018 (has links)
Orientadores: Maria Imaculada Zucchi, Ricardo Ribeiro Rodrigues / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-26T12:21:20Z (GMT). No. of bitstreams: 1 Schwarcz_KaiserDias_D.pdf: 5972760 bytes, checksum: 6089d106796adfd5fab684651bfb298e (MD5) Previous issue date: 2014 / Resumo: A degradação ecológica e o desflorestamento são processos que se iniciaram há muito tempo e cuja história confunde-se com a da agricultura. A Mata Atlântica é a segunda maior floresta tropical em ocorrência e importância na América do Sul, possuindo grande diversidade biológica e altos níveis de endemismo. A ocupação desordenada da Mata Atlântica causou sua redução a 11,26% de sua área original, com distribuição de forma fragmentada pelo território brasileiro. A destruição da Mata Atlântica tem resultado na eliminação de muitas populações e, potencialmente, na erosão da diversidade genética de diversas espécies. Essa combinação de alto endemismo e forte ameaça de extinção, faz com que a Mata Atlântica seja considerada um hotspot para a conservação. Nas últimas décadas a recuperação de ecossistemas degradados recebeu a atenção da comunidade científica, dando origem ao campo do conhecimento chamado Ecologia da Restauração, que se dedica aos estudos teóricos dos princípios, práticas, resultados e conseqüências de projetos de restauração. O estudo e monitoramento de áreas de restauração florestal é essencial para melhorar as técnicas de restauração em ecossistemas tropicais e subtropicais. Para que uma determinada espécie se perpetue em uma área em processo de restauração, é preciso que a mesma desenvolva todo o seu ciclo de vida e que gerem descendentes capazes de se desenvolver a ponto de substituir as árvores mães quando as mesmas entrarem em senescência. Por isso há a necessidade de se estudar a variabilidade genética de populações arbóreas dentro de áreas de floresta restaurada, assim como a ocorrência e efetividade do fluxo gênico entre estas áreas e os fragmentos de seu entorno. Neste trabalho, estudamos a variabilidade genética de Myroxylon peruiferum L. f., em duas diferentes áreas de restauração florestal e em duas áreas de remanescentes naturais de Floresta Estacional Semidecidual. Nossos resultados indicam que as restaurações florestais de Cosmópolis e Iracemápolis conservam diversidades genéticas HE e alélicas semelhantes às de remanescentes naturais. A principal diferença entre áreas naturais e restauradas foi a menor riqueza de alelos endêmicos nestas últimas o que é um efeito de amostragem que favorece a perda de alelos raros. A área de restauração florestal mais antiga em Cosmópolis apresentou uma estruturação genética espacial compatível com a de áreas naturais. O mesmo não ocorreu com a restauração mais recente de Iracemápolis. Observou-se a ocorrência de estruturação genética local nas áreas naturais e na área de restauração mais antiga e indícios de fluxo gênico entre os áreas nativas e restauradas. Um estudo adicional do efeito de amostragem sobre as freqüências alélicas demonstrou o fenômeno de perda de alelos com baixa freqüência em eventos de amostragem. O mesmo trabalho indicou que uma amostra de cerca de 30 indivíduos é capaz de representar adequadamente alelos com freqüências acima de 0,05; sendo este um bom número a se considerar na seleção de matrizes para fornecimento de mudas para restauração florestal / Abstract: Ecological degradation and deforestation are processes that started long ago and whose history is intertwined with that of agriculture. Atlantic Forest is the second largest rainforest in occurrence and importance in South America, having great biological diversity and high levels of endemism. Disordered occupation of Atlantic Forest caused its reduction to 11.26% of the original area, with distribution in forest fragments poorly conected across the Brazilian territory. Destruction of the Atlantic Forest has resulted in the elimination of many populations and potentially the erosion of genetic diversity of several species. This combination of high endemism and strong threat of extinction causes the Atlantic Forest to be considered a hotspot for conservation. In the last decades recovery of degraded ecosystems has received attention from the scientific community giving birth to an new area of knowledge called the Restoration Ecology. The study and monitoring of areas of forest restoration is essential to improve restoration techniques in tropical and subtropical ecosystems. For a given species to perpetuate itself in an area undergoing a restoration process, it needs to develop its whole life cycle and generates progeny capable of developing to the point of replacing mothers trees when they die. Therefore there is a need to study the genetic variability of tree populations within areas of restored forest, as well as the occurrence and effectiveness of gene flow between these areas and surrounding fragments. We studied the genetic variability of Myroxylon peruiferum L. f., in two different areas of forest restoration and in two areas of natural remnants of semideciduous forest. Our results indicates that restorations in Cosmopolis and Iracemápolis conserve genetic and allelic diversity HE similar to that of natural remnants. The main difference between natural and restored areas was the lowest richness of endemic alleles which is the result of a sampling effect that favors the loss of rare alleles. The area of older forest restoration in Cosmopolis presented a spatial genetic structure consistent with natural areas. This did not occur with the newer restoration in Iracemápolis. We observed the occurrence of local genetic structure in natural areas and in the area of older restoration and evidence of gene flow between native and restored areas. An additional study about the effect of sampling size on allele frequencies showed the phenomenon of loss of low frequency alleles in sampling events. The same study found that a sample of about 30 individuals are able to adequately represent alleles with frequencies above 0.05; this is a good number to consider in selecting matrix trees to supply seedlings for forest restoration / Doutorado / Genetica Vegetal e Melhoramento / Doutor em Genetica e Biologia Molecular
362

Caracterização da estrutura genética populacional das araras vermelhas Ara chloropterus e Ara macao (Psittaciformes, Aves) / Characterization of the population genetic structure of red macaws Ara chloropterus and Ara macao (Psittaciformes, Aves)

Adriana Ribeiro de Oliveira Marques 28 January 2011 (has links)
O objetivo do presente estudo foi caracterizar a estrutura genética populacional de duas espécies de araras: Ara chloropterus e Ara macao. Foram analisadas amostras de sangue e penas de diferentes regiões no Brasil, de uma localidade na Bolívia e outra no Peru. Foram realizadas análises com DNA mitocondrial (região controladora e citocromo oxidase I) e nuclear (microssatélites) das duas espécies. Para A. chloropterus foram obtidos 2166 pares de base do DNA mitocondrial de 89 amostras e dados de seis locos de microssatélites de 95 amostras. A rede de haplótipos e a árvore de neighbor-joining construídas com dados mitocondriais e os índices de FST obtidos com os dois marcadores revelaram fraca estruturação genética. Isso pode ser devido a alto fluxo gênico apresentado ou retenção de polimorfismo ancestral. Portanto, a espécie parece se organizar em metapopulações (baixa estruturação genética e alto fluxo gênico). Nesse caso, seria interessante conservar indivíduos de diversas localidades e seus corredores. Para Muscular Dystrophy foram obtidos 2094 pares de base do DNA mitocondrial de 68 amostras e dados de sete locos de microssatélites de 64 amostras. A rede de haplótipos e a árvore de neighbor-joining construídas com dados mitocondriais e os índices de FST obtidos com os dois marcadores indicam ausência de diferenciação genética entre as localidades estudadas. A análise demográfica dessa espécie indica expansão populacional há pouco mais de 50.000 anos atrás e declínio populacional desde o último período máximo de glaciação. Estes resultados sugerem que essa espécie é constituída de uma única grande população que poderia ser considerada como uma única unidade de manejo caso outras diferenças (ex.: adaptações ecológicas locais) não sejam encontradas. Ambas as espécies estudadas apresentam alta diversidade genética, possivelmente devido a um intenso fluxo gênico dentro de cada uma. / The present study aimed to characterize the population genetic structure of two macaw species: Ara chloropterus and Ara macao. Samples from various localities in Brazil, one in Bolivia and another in Peru were analyzed. Mitochondrial (control region and cytochrome oxidase I) and nuclear (microsatellites) DNA were analyzed. For A. chloropterus 89 individuals had 2166 bp of mitochondrial DNA sequenced and 95 individuals were genotyped for six polymorphic microsatellite loci. Network and the neighbor-joining tree constructed based on mitochondrial data and FST values obtained with both molecular markers revealed weak genetic structure. This can be due to high gene flow or retained ancestral polymorphism. Thus, A. chloropterus seems to be organized in metapopulations (low genetic structure and high gene flow). Under this scenario, it would be desirable to preserve individuals from various locations and there corridors. For Muscular Dystrophy we obtained 2094 bp of mitochondrial DNA for 68 individuals and data on seven microsatellites for 64 individuals. The haplotype network and the neighbor-joining tree constructed based on mitochondrial data and FST values obtained with both molecular markers revealed no genetic differentiation among localities. The demographic analysis of this species indicated a population expansion 50,000 years ago and a population decline since the last glaciation maximum. These results suggest that this species is organized as a large population that could be considered as a single management unit for conservation purposes if other differences are not found (eg. local ecological adaptations). Both species have high genetic diversity, possibly due to extensive gene flow within each one.
363

Populaciono-genetička karakterizacija ambrozije (Ambrosia artemisiifolia L.) južnog dela Panonske nizije i peripanonskog prostora centralnog Balkana / Population-genetic characterization of common ragweed (Ambrosia artemisiifoliaL.) from the southern part of the Pannonian Plain and the Peripannonian region of the Central Balkan

Kočiš-Tubić Nataša 22 September 2014 (has links)
<p>Vrsta&nbsp;<em> Ambrosia&nbsp; artemisiifolia&nbsp; L.&nbsp;</em> (fam.&nbsp; Asteraceae)&nbsp; je&nbsp; jedna&nbsp; od&nbsp; najagresivnijih&nbsp; invazivnih&nbsp;biljaka&nbsp; kako&nbsp; u&nbsp; Evropi,&nbsp; tako&nbsp; i&nbsp; na&nbsp; globalnom&nbsp; nivou.&nbsp; Kao&nbsp; korovska&nbsp; vrsta&nbsp; uzrokuje&nbsp; velike&nbsp;ekonomske&nbsp; gubitke&nbsp; redukujući&nbsp; prinos&nbsp; poljoprivrednih&nbsp; kultura,&nbsp; a&nbsp; njena&nbsp; masovna&nbsp; produkcija&nbsp;polena stvara ozbiljne alergijske probleme kod ljudi. Kao invazivna vrsta, predstavlja dobar&nbsp;model za proučavanje procesa uključenih u biolo&scaron;ke invazije, koje se danas prepoznaju kao&nbsp;deo globalnih promena, predstavljajući jednu od glavnih pretnji biodiverzitetu, funkcionisanju&nbsp;ekosistema,&nbsp; poljoprivredi,&nbsp; ali&nbsp; i&nbsp; ljudskom&nbsp; zdravlju.&nbsp; U&nbsp; Evropi,&nbsp; ambrozija&nbsp; je&nbsp; &scaron;iroko&nbsp;rasprostranjena,&nbsp; ali&nbsp; jedno&nbsp; od&nbsp; područja&nbsp; sa&nbsp; najvećom&nbsp; incidencom&nbsp; ovog&nbsp; invazivnog&nbsp; korova&nbsp; je&nbsp;Panonska&nbsp; nizija.&nbsp; Po&nbsp; svom&nbsp; položaju,&nbsp; kao&nbsp; i&nbsp; karakteristikama&nbsp; samog&nbsp; područja,&nbsp; ovaj&nbsp; region&nbsp;predstavlja&nbsp; povoljno&nbsp; stani&scaron;te&nbsp; kako&nbsp; za&nbsp; introdukciju&nbsp; ambrozije&nbsp; iz&nbsp; različitih&nbsp; pravaca,&nbsp; tako&nbsp; i&nbsp; za&nbsp;njenu brzu ekspanziju u pomenutom području i &scaron;ire.&nbsp; U proteklih 30-40 godina ambrozija se&nbsp;&scaron;iri&nbsp; na&nbsp; peripanonsko&nbsp; područje,&nbsp; tačnije&nbsp; ka&nbsp; centralnim&nbsp; i&nbsp; južnim&nbsp; delovima&nbsp; Srbije.&nbsp; Uzimajući&nbsp; u&nbsp;obzir sve činjenice,&nbsp; cilj ovog istraživanja je bio genetička karakterizacija populacija ambrozije&nbsp;<br />sa područja Panonske nizije i peripanonskog prostora centralnog&nbsp; dela Balkanskog poluostrva.&nbsp;U&nbsp; svrhu&nbsp; ovoga,&nbsp; upotrebljeni&nbsp; su&nbsp; jedni&nbsp; od&nbsp; najpopularnijih&nbsp; i &nbsp;ajinformativnijih&nbsp; molekularnih&nbsp;markera u polju populacione genetike, mikrosateliti. Na području Panonske nizije utvrđen je&nbsp;visok nivo genetičke varijabilnosti i nizak nivo genetičke diferencijacije i struktuiranosti među&nbsp;ispitivanim&nbsp; populacijama, a najverovatnije kao posledica multiplih introdukcija i intenzivnog&nbsp;protoka gena među populacijama ispitivanog regiona. Suprotno, populacije sa peripanonskog&nbsp;prostora&nbsp; centralnog&nbsp; Balkana&nbsp; su&nbsp; pokazale&nbsp; niži&nbsp; nivo&nbsp; genetičkog&nbsp; diverziteta&nbsp; u&nbsp; odnosu&nbsp; na&nbsp;panonske populacije, sa izraženom inter-populacionom diferencijacijom. Potvrđeno je &scaron;irenje&nbsp;ambrozije&nbsp; u&nbsp; pravcu&nbsp; sever-jug&nbsp; na&nbsp; području&nbsp; peripanonskog&nbsp; prostora,&nbsp; kao&nbsp; i&nbsp; poreklo&nbsp; ovih&nbsp;populacija&nbsp; od&nbsp; populacija&nbsp; iz&nbsp; regiona&nbsp; Panonske&nbsp; nizije,&nbsp; ali&nbsp; bez&nbsp; isključivanja&nbsp; mogućeg&nbsp; upliva&nbsp;ambrozije&nbsp; iz&nbsp; drugih&nbsp; pravaca.&nbsp; Ova&nbsp; saznanja&nbsp; doprinose&nbsp; rasvetljavanju&nbsp; procesa&nbsp; introdukcije&nbsp; i&nbsp;ekspanzije&nbsp; ispitivane&nbsp; invazivne&nbsp; vrste&nbsp; na&nbsp; ovom&nbsp; području&nbsp; Evrope.&nbsp; Utvrđen&nbsp; visok&nbsp; potencijal&nbsp; u&nbsp;ekspanziji ambrozije i potencijalni pravci &scaron;irenja u ispitivanom području, mogu da doprinesu&nbsp;predviđanju dalje potencijalne ekspanzije ove vrste, &scaron;to bi moglo unaprediti mere kontrole i&nbsp;strategiju za suzbijanje &scaron;irenja ambrozije.</p> / <p><em>Ambrosia&nbsp; artemisiifolia&nbsp;</em> L.&nbsp; (fam.&nbsp; Asteraceae)&nbsp; is&nbsp; one&nbsp; of&nbsp; the&nbsp; most&nbsp; aggressive&nbsp; invasive&nbsp; plant&nbsp;species&nbsp; in&nbsp; Europe&nbsp; and&nbsp; globally.&nbsp; As&nbsp; weed&nbsp; species,&nbsp; common&nbsp; ragweed&nbsp; causes&nbsp; great&nbsp; economic&nbsp;losses by reducing the yield of agricultural crops, and its mass production&nbsp; of pollen produces&nbsp;severe allergic problems in humans. As an invasive species,&nbsp; <em>Ambrosia artemisiifolia&nbsp;</em> is&nbsp; a good&nbsp;model for studying the processes of biological invasions, which are today recognized as part&nbsp;of&nbsp; global&nbsp; changes,&nbsp; presenting&nbsp; a&nbsp; major&nbsp; threat&nbsp; to&nbsp; biodiversity,&nbsp; the&nbsp; functioning&nbsp; of &nbsp; ecosystems,&nbsp;agriculture and human health. In Europe, <em>Ambrosia artemisiifolia</em> is widespread, but one of the&nbsp;most&nbsp; infested&nbsp; area&nbsp; is&nbsp; the&nbsp; Pannonian&nbsp; Plain.&nbsp; According&nbsp; to&nbsp; location&nbsp; and&nbsp; characteristics&nbsp; of&nbsp; the&nbsp;area,&nbsp; this&nbsp; region&nbsp; represents&nbsp; a&nbsp; favorable&nbsp; habitat&nbsp; for&nbsp; introduction&nbsp; of&nbsp; common&nbsp; ragweed&nbsp; from&nbsp;different&nbsp; directions&nbsp; and&nbsp; rapid&nbsp; expansion&nbsp; in&nbsp; these&nbsp; areas&nbsp; as&nbsp; well&nbsp; as&nbsp; further.&nbsp; In&nbsp; the&nbsp; past&nbsp; 30-40&nbsp;years,&nbsp; common&nbsp; ragweed&nbsp; was&nbsp; spreading&nbsp; across&nbsp; Peripannonian&nbsp; region,&nbsp; more&nbsp; precisely,&nbsp; to&nbsp; the&nbsp;Central and Southern parts of Serbia. According the facts, the aim of this study was the genetic&nbsp;characterization&nbsp; of&nbsp; populations&nbsp; of&nbsp; <em>Ambrosia&nbsp; artemisiifolia&nbsp;</em> from&nbsp; the&nbsp; Southern&nbsp; part&nbsp; of&nbsp; the&nbsp;Pannonian Plain and the&nbsp; Peripannonian region of the Central Balkan.&nbsp; One of the most popular&nbsp;and most informative molecular markers in&nbsp; population genetics, microsatellites&nbsp; were&nbsp; used. In&nbsp;the area of the Pannonian Plain, a high level of&nbsp; genetic variability and low&nbsp; level of&nbsp; genetic&nbsp;differentiation and structure&nbsp; among the study population have detected, probably as a&nbsp; result of&nbsp;multiple&nbsp; introduction&nbsp; and&nbsp; intensive&nbsp; gene&nbsp; flow&nbsp; between&nbsp; populations.&nbsp; In&nbsp; the&nbsp; other&nbsp; hand,&nbsp; the&nbsp;populations from the Peripannonian region have shown lower level of genetic diversity related&nbsp;to&nbsp; populations&nbsp; from&nbsp; Pannonin&nbsp; Plain,&nbsp; with&nbsp; moderate&nbsp; level&nbsp; of&nbsp; inter-population&nbsp; differentiation.&nbsp;Obtained&nbsp; results&nbsp; have&nbsp; confirmed&nbsp; that&nbsp; the&nbsp; spread&nbsp; of&nbsp; common&nbsp; ragweed&nbsp; across&nbsp; Peripannonian&nbsp;region was&nbsp; in the north-south direction, as &nbsp;well as that the populations from the considered&nbsp;area originated from the populations of Pannonian Plain.&nbsp; However, in this claim we can not&nbsp;exclude&nbsp; the&nbsp; possible&nbsp; influence&nbsp; of&nbsp; <em>Ambrosia&nbsp; artemisiifolia</em>&nbsp; from&nbsp; other&nbsp; directions.&nbsp; This&nbsp; study&nbsp;contributes&nbsp; to&nbsp; better understuding of&nbsp; the process of introduction and expansion of&nbsp; <em>Ambrosia&nbsp;artemisiifolia&nbsp;</em> in&nbsp; considered part&nbsp; of Europe.&nbsp; Detected&nbsp; high potential for &nbsp;expansion of&nbsp; common&nbsp;ragweed and possible directions of spreading in the study area, can contribute to the prediction&nbsp;of&nbsp; potential&nbsp; further&nbsp; expansion&nbsp; of&nbsp; <em>Ambrosia&nbsp; artemisiifolia</em>,&nbsp; which&nbsp; could&nbsp; improve&nbsp; control&nbsp;measures and strategies for preventing the spreading of this invasive species.&nbsp;</p>
364

Ochranářská genetika vlka obecného ve střední Evropě / Conservation genetics of the grey wolf in Central Europe

Valentová, Kamila Anna January 2021 (has links)
Conservation genetics of the grey wolf in Czech Republic and adjacent regions is studied in the present thesis. Analyses of twenty-one microsatellite loci, one sex-determining amelogenin gene and mitochodrial control region were used to verify species determination, identify individuals and estimate relationships between them, analyse population structure and estimate demographic trends based on samples collected between 2014 and 2021. Genetic detection of red fox and dog samples incorrectly assigned to wolves illustrates the hurdles of field monitoring of grey wolf. Direct evidence for the occurrence of F1 hybrids was not found. Wolves from Bohemia showed lower values of allelic richness in comparison to the ones from Western Carpathians, probably as a consequence of recent expansion. Geographic distances between detection sites of identical individuals were relatively small or moderate in this study, suggesting regular movements of animals within their home ranges. Only two long-distance dispersal events exceeding 300 km were detected. Results of parental analysis provided evidence of pack distribution within the studied area. Most relationships were detected between wolves in the northern region of Czech Republic where the first recolonizing wolf pack in 2014 was registered. Within the studied...
365

Vnitřní struktura balkánského refugia na modelu Erinaceus roumanicus / Internal structure of the Balkan refugium using Erinaceus roumanicus as a model organism

Eliášová, Kristýna January 2014 (has links)
The aim of this work was to describe the spatial distribution of genetic variability of the northern white-breasted hedgehog (E. roumanicus), mainly within the Balkan Peninsula and Central Europe, as these areas are crucial for understanding the effects of Pleistocene climate oscillations on the genetic architecture of the species. Based on this spatial distribution, hypotheses about the possible structuring of the Balkan refugia were formulated. A total of 260 individuals and 9 microsatellite loci were used for the analysis. Using the approach of landscape and population genetics several possible isolated subpopulations within the area surveyed were identified. Unique status was proved for a population originating from Crete, probably influenced by mechanisms of island evolution. Differences from the rest of the range were ascertained also in population from the Czech Republic, located in a secondary contact zone with the E. europeaus. The role of interspecific interactions and possible introgression should be considered in this case. In the area of Romania and the area south of the Balkan Peninsula the highest genetic distances between individuals were identified, probably associated with the occurrence of geographical barriers and the possible presence of glacial subrefugia. Other identified...
366

Ekologické důsledky polyploidizace u mokřadní rostliny šmelu okoličnatého (Butomus umbellatus) / Ecological consequences of polyploidization in populations of the wetland plant Butomus umbellatus

Rydlo, Jan January 2016 (has links)
This thesis aimed on comparison of environmental requirements and morphological and biological traits of diploid and triploid cytotypes of wetland plant flowering rush (Butomus umbellatus), occurring in Eastern Slovak Lowland in unique mixed populations, and to develop primers for variable microsatellite loci suitable for further genetic studies. In total, 72 populations of Butomus umbellatus were found. The analysis of relative genome size by the flow cytometry (FCM) technique revealed 34 exclusively triploid cytotype populations, 8 exclusively diploid populations and 30 mixed populations of Butomus umbellatus. In mixed populations, the numbers of diploid and triploid individuals are quite equivalent and the plants create combined compact communities. Analyses of environmental characteristics of sites with specific cytotypes (PCA, RDA, ANOVA) revealed no difference in site requirements of diploid and triploid Butomus umbellatus plants. Morphometric analyses (PCA, CDA) of traits of 36 diploid and 54 triploid plants confirmed differing morphology of both cytotypes occurring in the nature. Subsequent replanting of these plants into pots and cultivation further increased these differences. The ratio of width and length of internal perianthium is the most reliable parameter to distinguish diploid and...
367

Wild bee communities in restored sand ecosystems in north-western Germany: Community structure, population genetics and habitat preferences

Exeler, Nina 25 March 2009 (has links)
In north-western Germany, inland dunes and natural floodplains were widespread in the past. Due to the regulation of the natural course, large rivers have experienced serious anthropogenic influences resulting in a decline of adjacent natural floodplains. The realization of a restoration project in north-western Germany had the aim to restore a floodplain composed of inland dunes and seasonally flooded grasslands. Within this project, the response of wild bee communities to such restoration measures was evaluated. Therefore, an analysis of the succession and distribution patterns of wild bee communities in restored and target habitats was conducted. In chapter 1 and 2 the success of the restoration measures was evaluated by a comparative analysis of wild bee communities at restoration and target sites. The results show a rapid colonization of a species-rich wild bee community reflecting a community composition which is composed of generalists, specialists and parasitic species. The quantity of entomophilous plant species and the proportion of bare ground had a strong influence on wild bee species composition. To gain insight into the connectivity of wild bee populations, the population genetic structure of two wild bee species, Andrena vaga and Andrena fuscipes was analysed in chapter 3 and 4. Additionally, general intrinsic factors that maintain the genetic diversity and influence the degree of inbreeding were evaluated in chapter 5 on the basis of an extensive literature survey. These results reflect a high dispersal ability and inter-population movement of wild bees. For both species a high genetic diversity within populations and a low genetic differentiation among populations was found. In conclusion, wild bees proved to be useful indicators for monitoring the effects of restoration projects. The combination of population genetic analyses and community monitoring provides the opportunity to evaluate different aspects of restoration success.
368

Molecular Ecology of Globally Distributed Sharks

Testerman, Christine B. 01 April 2014 (has links)
Many sharks have life history characteristics (e.g., slow growth, late age at maturity, low fecundity, and long gestation periods) that make their populations vulnerable to collapse due to overfishing. The porbeagle (Lamna nasus), bull shark (Carcharhinus leucas), great hammerhead (Sphyrna mokarran), and smooth hammerhead (S. zygaena), are all commercially exploited. The population genetic structure of these species was assessed based on globally distributed sample sets using mitochondrial control region (mtCR) sequences and/or nuclear markers. Complex patterns of evolutionary and demographic history were inferred using coalescent and statistical moment-based methods. All four species showed statistically significant genetic partitioning on large scales, i.e., between hemispheres (L. nasus mtCR φST = 0.8273) or oceanic basins (C. leucas nuclear FST = 0.1564; S. mokarran mtCR φST = 0.8745, nuclear FST = 0.1113; S. zygaena mtCR φST = 0.8159, nuclear FST = 0.0495). Furthermore, S. zygaena mtCR sequences indicated statistically significant matrilineal genetic structuring within oceanic basins, but no intrabasin structure was detected with nuclear microsatellites. S. mokarran showed statistically significant genetic structure between oceanic basins with both nuclear and mitochondrial data, albeit with some differences between the two marker types in fine scale patterns involving northern Indian Ocean samples. A microsatellite assessment of C. leucas demonstrated no population structuring within the Atlantic or Indo-Pacific, with the exception that samples from Fiji were differentiated from the remaining Indo- Pacific Ocean locations. In contrast, the L. nasus mitochondrial and nuclear ITS2 sequences revealed strong northern vs. southern hemispheric population differentiation, but no differentiation within these hemispheres. These geographic patterns of genetic structure were used to determine the source of fins obtained from the international fin trade and to develop forensic tools for conservation.
369

Microsatellites and their association with break induced replication

Damewood, French J., IV January 2021 (has links)
No description available.
370

Sistemática, procesos de especiación, estrategias reproductivas y estructura genética en Ruppia / Systematics, speciation processes, reproductive strategies and genetic structure in Ruppia

Martínez-Garrido, Jose 07 July 2017 (has links)
Las plantas acuáticas del género Ruppia habitan lagunas costeras, salinas, humedales y aguas salinas interiores, jugando un papel ecológico clave. Estos sistemas se caracterizan por variaciones extremas de las condiciones ambientales tales como salinidad, temperatura e inundación. La compleja historia evolutiva del género Ruppia ha dificultado la delimitación de especies en el género. Estas especies han desarrollado una gran diversidad de estrategias biológicas para sobrevivir en estos ambientes extremos, tales como ciclos de vida anuales y perennes, reproducción sexual y propagación vegetativa, estrategias de polinización epihidrófila e hidroautogámica, así como autofecundación y fecundación cruzada. Además, existen diferentes vectores que pueden facilitar el flujo de genes entre las poblaciones, incluyendo corrientes marinas, aves acuáticas y peces. Estas características biológicas de Ruppia tienen una influencia importante en sus patrones de especiación, diversidad genotípica y genética, y su estructura poblacional. Por lo tanto, los análisis genéticos proporcionan información importante para delimitar especies y taxones dentro de este género, evaluar la diversidad e identificar procesos y flujos que actúan a distintas escalas temporales y espaciales. Los objetivos principales de esta tesis son: inferir los procesos evolutivos y biológicos de especiación y diversificación, y evaluar la prevalencia y estructura poblacional de especies Europeas del género Ruppia. Esta tesis se centra principalmente en las zonas costeras de la Península Ibérica, debido a la alta diversidad de especies de Ruppia registradas en esta zona geográfica, y al hecho de que en muchas ocasiones es posible encontrar poblaciones de diferentes especies en simpatría. Para alcanzar estos objetivos, en el Capítulo I, se desarrollaron y validaron diez nuevos marcadores moleculares polimórficos (es decir, microsatélites) para Ruppia cirrhosa. Adicionalmente se obtuvo amplificación cruzada con otros dos microsatélites descritos anteriormente para R. maritima. Estas herramientas moleculares son importantes para el estudio de plantas clonales y se han utilizado junto con secuencias nucleares y del cloroplasto en los siguientes capítulos. En el Capítulo II, se estudió la sistemática del género Ruppia en Iberia considerando criterios morfológicos, marcadores nucleares altamente variables (microsatélites) y secuencias nucleares (ITS) y del cloroplasto (psbA-trnH). Al realizar la filogenia utilizando marcadores con diferentes tiempos de mutación y mecanismos hereditarios, pudo identificarse el importante papel de la hibridación y la introgresión en la historia evolutiva de este género. De las tres especies tradicionalmente descritas en la Península Ibérica, se observó que R. drepanensis y R. cirrhosa se situaron en el mismo clado filogenético tanto para los marcadores nucleares como para los cloroplastos, por lo que pueden considerarse especies hermanas. R. maritima está incluida en un clado más distante filogenéticamente, apoyado por ambos marcadores. Además, dos nuevas entidades genéticas fueron identificadas, R. cf. maritima y "R. híbrido", las cuales mostraron algunas incongruencias entre los árboles filogenéticos del núcleo y del cloroplasto, así como una combinación de alelos de microsatélites que sugieren la existencia de efectos de hibridación y/o introgresión. En el Capítulo III, mediante el estudio de microsatélites en diferentes poblaciones de R. cirrhosa de la Península Ibérica y Sicilia, se detectó una fuerte estructura genética poblacional. En términos generales, se registró un bajo nivel de flujo génico, el cual fue más importante entre poblaciones geográficamente cercanas o ubicadas en el mismo cuerpo hidrológico. Además, se evaluaron diferentes hipótesis para explicar la conectividad entre las poblaciones a través de correlaciones entre distancias geográficas y genéticas, sugiriendo que el vector de dispersión más probable entre las poblaciones de R. cirrhosa en la Península Ibérica son las aves acuáticas. Al compilar los resultados del Capítulo II y el Capítulo III, se evaluaron los efectos de diferentes estrategias reproductivas sobre la diversidad genotípica y genética de Ruppia. Todas las entidades genéticas mostraron elevadas tasas de reproducción sexual. En R. cirrhosa, los mayores índices de reproducción sexual se detectaron en los hábitats más inestables hidrológicamente. Estas perturbaciones podrían promover la germinación y el establecimiento de semillas por una baja competencia interespecífica por el espacio, la luz y otros recursos existentes en praderas menos densas. Los mayores valores de diversidad genética detectados en los epihidrófilos R. drepanensis, R. cirrhosa y probablemente en “R. híbrido” (ésto no se ha confirmado) que en la hidroautogámica Ruppia cf. maritima, sugieren una fuerte influencia del modelo de polinización sobre los patrones de diversidad genética. En el Capítulo IV, R. maritima fue identificada por primera vez en Cabo Verde (Isla de Santiago) a partir de análisis morfológicos y filogenéticos. Esta información amplía la distribución geográfica de esta especie al África Occidental.

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