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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

Genômica de populações e genética geográfica de bovinos Pantaneiros e Curraleiro Pé-Duro com uso de polimorfismos de base única (SNP) / First report of population genomics in pantaneiro and Curraleiro Pé-Duro catle using single nucleotide polymorphisms (SNP) and a geographical genetics approach

Silva, Marcelo Corrêa da 21 September 2015 (has links)
Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2016-04-18T10:48:49Z No. of bitstreams: 2 Tese - Marcelo Corrêa da Silva - 2015.pdf: 7209207 bytes, checksum: c24f13fb20a00a3bc5b7d242ee956d69 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-04-18T10:51:37Z (GMT) No. of bitstreams: 2 Tese - Marcelo Corrêa da Silva - 2015.pdf: 7209207 bytes, checksum: c24f13fb20a00a3bc5b7d242ee956d69 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2016-04-18T10:51:37Z (GMT). No. of bitstreams: 2 Tese - Marcelo Corrêa da Silva - 2015.pdf: 7209207 bytes, checksum: c24f13fb20a00a3bc5b7d242ee956d69 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2015-09-21 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Livestock production has played a major role in social-economic aspects of rural development worldwide. In South America the introduction of domestic breeds such as cows, sheep and goats occurred during Spanish and Portuguese colonization expeditions over five hundred years ago. The Pantaneiro and Curraleiro Pé-Duro cattle breeds originate from this exact context and resemble historic, cultural and ecological aspects of traditional cattle farming in Brazil. This is characterized by rough and extensive breeding systems placed in many ecosystems of this country. Small population sizes and severe loss of genetic diversity in livestock breeds are of great concern regarding the scenario of global warming, emphasis on the sustainability of farming activities, the need of alternatives to attend market trends and promote rural development in a local perspective. This study was undertaken to explore patterns of genetic diversity in Pantaneiro e Curraleiro Pé-Duro cattle, aiming to identify differences between groups reared in several regions of Central-West, Central, North and Northeast of Brazil. Animals were genotyped using a SNP (single nucleotide polymorphism) chip containing over fifty thousand markers. Different analytical procedures were carried out using differentiation index, estimates of common ancestry, simple and multivariate clustering, inbreeding coefficients, genetic and also geographical distances. Spatial analysis was developed to allow the identification of patterns of genetic variation, specific geographical regions and herds of greater genetic differentiation. The results furnish insights in order to develop strategies to preserve genetic variability in Pantaneiro and Curraleiro Pé-Duro cattle. / Os bovinos são tradicionalmente utilizados como fonte de proteína animal na alimentação humana em diversas regiões do mundo. Na América do Sul esta espécie foi introduzida por colonizadores espanhóis e portugueses e há mais de 500 anos tem sido disseminada no Brasil com importância alimentar e socioeconômica. Bovinos Pantaneiros e Curraleiro Pé-Duro são remanescentes de bovinos trazidos da região ibero-americana por meio de navios. Atualmente são considerados patrimônios históricos e culturais do país, com destaque à pecuária extensiva e tradicional que é praticada em diversos biomas do interior do Brasil, como o Pantanal, o Cerrado e a Caatinga. O baixo número de indivíduos existente, a demanda por uma produção animal mais competitiva e economicamente viável, com potencial de agregação de valor ou diferencial em termos de rusticidade, tem sido favoráveis para a discussão da conservação e maior utilização de raças localmente adaptadas. Isso tem tido maior destaque também em função do advento do aquecimento global e maior valorização de especificidades que caracterizam circunstâncias sociais, ecológicas e produtivas em escala local. Assim, este estudo foi desenvolvido a fim de explorar e compreender padrões de diversidade genética em populações de bovinos Pantaneiros e Curraleiro Pé-Duro, investigando-se diferenças e semelhanças genéticas entre indivíduos e rebanhos amostradas em diferentes biomas das regiões centro oeste, norte e nordeste do Brasil. Bovinos foram amostrados e genotipados com uso de um chip contendo mais de 50 mil marcadores polimórficos de base única (single nucleotide polymorphism, SNP). Diferentes técnicas de análise genética foram realizadas como o uso de distância genéticas, índices de diferenciação genética, estimativas de ancestralidade comum, endogamia e análises de dispersão e agrupamento uni e multivariados. Foram utilizados métodos de estatística espacial, que possibilitaram a identificação de padrões de variabilidade genética em função de distâncias geográficas e a identificação de descontinuidades genéticas, revelando uma compreensão inédita acerca da diferenciação entre grupos formados com base em um critério geopolítico ou com base em similaridade genética. Os resultados obtidos fornecem subsídios para a formação de grupos experimentais, a troca de material genético entre criadores, planejamentos participativos para a preservação e gestão sustentável desses bovinos junto às associações de criadores, entidades de pesquisa e demais atores envolvidos.
2

Developing saddleback and emperor tamarin SNP set for in situ genotyping

López Clinton, Samantha January 2022 (has links)
Many countries in the global south - which harbour the majority of the world’s biodiversity - face serious resource limitations and a lack of access to affordable sequencing services. Furthermore, biodiversity research and monitoring of non-model, threatened and/or cryptic species often relies on low-quality non-invasive genetic samples. In situ conservation genomics approaches optimised for field conditions and low-quality DNA can help empower local researchers and meet their needs. To do so, however, accessible and reproducible sequencing and genotyping alternatives are needed. I designed a SNP panel as a field-friendly genotyping approach for two species of Amazonian primates using both high- and low-quality DNA samples, and two different sequencing platforms, Illumina and Nanopore. I used 14 high-quality genomes to identify a set of 210 SNPs that allow for identification of species (twelve SNPs), sex (twelve SNPs) and individual identity (186 SNPs) in two species of tamarins, Leontocebus weddelli and Saguinus imperator. Primers, adapters and indexes were designed in a Genotyping-in-Thousands by sequencing approach that is compatible with both sequencing platforms. This approach is based on sequencing multiplexed PCR products of a few hundred target SNPs to genotype thousands of individuals in a single sequencing run. In an effort to make conservation genomics more accessible, the reproducible pipeline to obtain the informative SNPs is being modulated with Snakemake, a workflow management system. / Muchos países en el sur global - los cuales poseen la mayoría de la biodiversidad mundial - enfrentan serias limitaciones de recursos y una falta de acceso a servicios económicos de secuenciación. Con frecuencia, la investigación y el monitoreo de biodiversidad y especies no-modelo, amenazadas y/o crípticas, dependen de muestras genéticas no-invasivas de baja calidad. La genómica de la conservación in situ optimizada para condiciones de campo y ADN de baja calidad puede empoderar a investigadorxs locales y ayudarles a responder a sus necesidades. Para ello, sin embargo, se requieren alternativas accesibles y reproducibles de secuenciación y genotipado. Diseñé un panel de SNPs como una aproximación de genotipado apta para el campo y dirigida a dos especies de primates amazónicos con el uso de ADN de baja y alta calidad, y dos plataformas de secuenciación (Illumina y Nanopore). Usé 14 genomas de alta calidad para encontrar 210 SNPs que permiten la identificación de la especie (doce SNPs), del sexo (doce SNPs) y de la identidad individual (186 SNPs) en dos especies de pichicos, Leontocebus weddelli y Saguinus imperator. Los cebadores, adaptadores e índices fueron diseñados con un enfoque de Genotyping-in-Thousands by sequencing (Genotipado en los miles por secuenciación) que es compatible con ambas plataformas de secuenciación. Este método está basado en la secuenciación de productos de PCR multiplexados de unos cientos de SNPs para genotipar miles de individuos en una sola corrida de secuenciación. En un intento de mejorar la accesibilidad de la genómica de la conservación, el proceso reproducible para obtener a los SNPs informativos está siendo modulado con Snakemake, un sistema de manejo de flujos de trabajo.
3

Detecting structural variants in the DNA of the inbred Scandinavian wolf

Huson, Lars January 2023 (has links)
Only 40 years ago, just three individuals made the journey from Finland/Russia to found the current wolf population in the southwest of Sweden. This population, that to this date descends from less than 10 founders, has a substantial increased extinction risk due to inbreeding. Several previous studies have used SNPs to monitor the level of inbreeding and homozygosity in the population, as well as measure immigration and the inflow of new genetic material. This study uses both short- and long-read data to discover structural variants (SVs) and small indels in the population, so that they may be used to extend the analyses and provide more insight into the current state of the Scandinavian wolf population. After the calling of the SVs, strict filtering and manual curation were applied to the data, thereby removing many false positive calls and increasing confidence in the remaining SVs. Short-read and long-read SV-callers found 31,800 and 57,821 SVs respectively, with relatively little overlap between the two sets. By far, the most common SV-types were deletions and insertions, at about 30,000 each with varying length ranging from a 50 base pairs to several tens of Mbp. Analyses on the data, such as PCAs and parent-offspring trio analyses, reveal high-confidence calls and consistent results between SV-types and SV-callers, as well as a low estimated genotyping error rate. PCAs performed on the SVs resembled those performed on SNPs, which strengthens the credibility of the identified variants. Finally, this study suggests several alternative steps for possible improvement to the dataset, along with some proposals for subsequent research topics that may use the variants discovered in this study.

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