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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.
11

Population Structure and Genetic Diversity of the North Atlantic Right Whale (Eubalena Glacialis)

Malik, Sobia 12 1900 (has links)
The North Atlantic right whale (Eubalaena glacialis) is the most endangered species of large whale in the world (IUCN). Efforts for the recovery of this species were initiated almost 20 years ago, yet the North Atlantic right whale shows little signs of recovery. Reliance on particular habitat areas and the effect of factors such as ship collisions, net entanglement and habitat disturbances are hampering the recovery of this species. Therefore, it is important to assess the level of genetic diversity left in this population and to identify and assess all habitat areas for potentially lethal threats. This study has identified a subset of the reproductive females that do not use the Bay of Fundy as a nursery area, through the genetic structuring of mtDNA control region haplotypes. Genetic structuring of the control region haplotypes was established and maintained by site fidelity of reproductive females to specific nursery areas. These results have identified a list of reproductive females that will be the targets of satellite tagging to elucidate the location of the alternative nursery area(s) to the Bay of Fundy. Analysis of mtDNA control region haplotypes in North and South Atlantic right whale has identified five haplotypes in the 180 North Atlantic right whales analyzed compared to 10 haplotypes in the 16 South Atlantic right whales analyzed. The low level ofhaplotypic variability in the North Atlantic right whale is a direct consequence of the extensive whaling period endured by this species. The genetic divergence between the North and South Atlantic right whales was estimated to have occurred 3.0-9.0 mya. This is similar to the genetic divergence of 2.0-5.3 mya found between the two clades identified in the South Atlantic samples. / Thesis / Master of Science (MSc)
12

Evolutionary genetics of the house mouse (Mus musculus domesticus) with particular emphasis on chromosomal and mitochondrial DNA variation

Gündüz, Islam January 1999 (has links)
No description available.
13

Sobre a origem e dispersão da mutação do gene PLAG1 em bovinos /

Utsunomiya, Yuri Tani. January 2017 (has links)
Orientador: José Fernando Garcia / Banca: Johann Sölkner / Banca: Flávia Lombardi Lopes / Banca: Paolo Ajmone Marsan / Banca: Celso Luis Marino / Resumo: O gene 1 do adenoma pleomórfico (PLAG1) apresenta evidência de seleção positiva recente e associação com tamanho corporal e fertilidade em um grande número de raças bovinas ao redor do mundo. Tendo em vista sua recentemente descoberta função como fator de transcrição para o gene do fator de crescimento semelhante à insulina 2 (IGF2), o PLAG1 possui papel emergente como um dos principais reguladores do crescimento e da reprodução em bovinos. Apesar de sua importância, a variante de sequência de DNA responsável pelos efeitos pleiotrópicos atribuídos ao PLAG1 em bovinos permanece desconhecida. Também não está claro se a mesma mutação explica as associações fenótipo-genótipo encontradas em diferentes populações bovinas. Além disso, ainda é incerto onde e quando ocorreu a pressão de seleção responsável pelo aumento da frequência da mutação do PLAG1. No presente trabalho, reportamos o desenvolvimento de um pacote para o software estatístico R, o qual é direcionado à análise de haplótipos como preditores para variantes genéticas não observadas. Através da aplicação desta ferramenta a dados genômicos de bovinos oriundos de diversas regiões do mundo, encontramos evidência indicando que um único alelo derivado do PLAG1 aumentou em frequência rapidamente em bovinos Bos taurus do noroeste europeu entre os séculos XVI e XVIII. Este período é reconhecido como a última onda de aumento de estatura em bovinos por meio de registros arqueológicos. Os dados também sugerem que o alelo foi introgr... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The pleomorphic adenoma gene 1 (PLAG1) presents both evidence of recent positive selection and association with body size and fertility in a wide range of worldwide cattle breeds. Considering its recently uncovered function as a transcription factor for the insulin-like growth factor 2 gene (IGF2), PLAG1 is emerging as a major regulator of bovine growth and reproduction. In spite of its importance, the causal DNA sequence variant underlying the pleiotropic effects of PLAG1 in cattle remains unknown. It is also unclear whether the same mutation accounts for the phenotype-genotype associations detected across different cattle populations. Furthermore, when and where the selective pressure responsible for increasing the frequency of the PLAG1 mutation occurred is still uncertain. Here, we report the development of a package for the R statistical software to analyze haplotypes as surrogates for unobserved genetic variants. By applying this tool to genomic data of worldwide cattle breeds, we found evidence that a single bovine PLAG1 derived allele increased rapidly in frequency in Northwestern European Bos taurus populations between the 16th and 18th centuries. This period is recognized as the last wave of increase in bovine stature from archaeological data. The data also suggested that the allele was introgressed into non-European B. taurus and Bos indicus breeds towards the 19th and 20th centuries, achieving an almost global distribution in the last century. Ancient DNA analyses... (Complete abstract click electronic access below) / Doutor
14

Approaches to Estimation of Haplotype Frequencies and Haplotype-trait Associations

Li, Xiaohong 01 February 2009 (has links)
Characterizing the genetic contributors to complex disease traits will inevitably require consideration of haplotypic phase, the specific alignment of alleles on a single homologous chromosome. In population based studies, however, phase is generally unobservable as standard genotyping techniques provide investigators only with data on unphased genotypes. Several statistical methods have been described for estimating haplotype frequencies and their association with a trait in the context of phase ambiguity. These methods are limited, however, to diploid populations in which individuals have exactly two homologous chromosomes each and are thus not suitable for more general infectious disease settings. Specifically, in the context of Malaria and HIV, the number of infections is also unknown. In addition, for both diploid and non-diploid settings, the challenge of high-dimensionality and an unknown model of association remains. Our research includes: (1) extending the expectation-maximization approach of Excoffier and Slatkin to address the challenges of unobservable phase and the unknown numbers of infections; (2) extending the method of Lake et al. to estimate simultaneously both haplotype frequencies and the haplotype-trait associations in the non-diploid settings; and (3) application of two Bayesian approaches to the mixed modeling framework with unobservable cluster (haploype) identifiers, to address the challenges associated with high-dimensional data. Simulation studies are presented as well as applications to data arising from a cohort of children multiply infected with Malaria and a cohort of HIV infected individuals at risk for anti-retroviral associated dyslipidemia. This research is joint work with Drs. S.M. Rich, R.M. Yucel, J. Staudenmayer and A.S. Foulkes.
15

Gene-environment interactions in genetic epidemiology

Spinka, Christine Marie 17 February 2005 (has links)
Gene-environment interactions are an area of increasing interest in complex hu- man diseases. The first step in any study of the interactions between genes and the environment involves identifying genes which influence the trait of interest. In this dissertation, a new method for using the information in complex pedigrees to per- form a joint linkage disequilibrium and linkage mapping of quantitative trait loci is developed. Subsequently, methods are needed to determine the interaction, if any, between these genes and environmental risk factors. Many of these factors, such as weight or age, are continuous and little is known about their distributions. Thus, we introduce a new method for estimating the gene-environment interaction parameters in a logistic regression for the case-control study design. In doing so, we make the assumption that in the underlying population, the distributions of the genetic factors and the environmental covariates are independent. Additionally, we treat the envi- ronmental parameters nonparametricly, utilizing the profile likelihood. Furthermore, the methodology we develop is also general enough to be used on many different types of genetic information, including haplotypes, and can accommodate missing genotype data. The method is also extended to allow analysis in the presence of population stratification or genotype misclassification. We show that the standard errors of pa- rameter estimates using our method are smaller than those found using complete data only. These methods are illustrated using simulations and are applied to a real data set exploring the interaction between genotype and environment in disease risk.
16

Modeling and inference for linkage disequilibrium and recombination /

Li, Na, January 2003 (has links)
Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (p. 114-125).
17

Genetic profiling of drug resistance in Plasmodium falciparum /

Certain, Laura K. January 2007 (has links)
Thesis (Ph. D.)--University of Washington, 2007. / Vita. Includes bibliographical references (leaves 173-196).
18

APOE haplotypes in health, lessons from an Oklahoman African American population

Obregon Tito, Alexandra de. January 2010 (has links) (PDF)
Thesis--University of Oklahoma. / Bibliography: leaves 61-68.
19

Identificação de Single Nucleotilde Polymorphisms (SMPs) no gene Nove-cis-epoxicaroteníde dioxigenase (NCED) em Eucalyptus

Santoro, Andreia [UNESP] 17 December 2010 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:26:03Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-12-17Bitstream added on 2014-06-13T20:14:33Z : No. of bitstreams: 1 santoro_a_me_botib.pdf: 947565 bytes, checksum: 9b8b73aa8568ce2e4062e8221c067755 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Florestas de eucalipto no Brasil estão entre os ecossistemas mais produtivos do mundo. A madeira do eucalipto é principalmente utilizada pelas empresas de papel e celulose. Contudo, fatores abióticos e bióticos afetam a expansão dessas florestas. A disponibilidade de água é uma das maiores limitações para o desenvolvimento das espécies, afetando a produção de biomassa. O hormônio ácido abscísico (ABA) desencadeia respostas de resistência a estresses abióticos, em particular a seca. O objetivo deste trabalho foi identificar Single Nucleotide Polymorphisms (SNPs) no gene NCED (nove-cis-epoxicarotenóide dioxigenase), da rota biossintética do ácido abscísico (ABA), em Eucalyptus. Através da utilização da sequencia de aminoácido da enzima de Arabidopsis (AtNCED3) e do banco de dados de Expressed Sequence Tags (ESTs) de Eucalyptus foi possível o desenvolvimento de três oligonucleotídeos, os quais amplificaram a região desejada do gene. Então, primers específicos foram desenhados e os produtos de amplificação de diferentes indivíduos submetidos ao sequenciamento direto. O alinhamento e as análises das sequencias revelaram a ocorrência de sete SNPs no gene NCED, em uma região de 1230 pares de bases. A razão transição/transversão foi 1.33. Após a predição da proteína, no site Softberry e Expasy, foram verificados cinco SNPs presentes na região codificadora, os quais geraram mutações sinônimas. Através do software DnaSP, sete haplótipos foram encontrados na amostra de 65 indivíduos gerando 15 genótipos, distribuídos entre as espécies E. grandis, E. urophylla e no híbrido Urograndis. Para os sete sítios polimórficos foram desenhados conjuntos de primers específicos que permitirão a genotipagem em larga escala para estudos de genética de população e em programas de melhoramento assistido / Eucalyptus plantations in Brazil are among the most productive ecosystems in the world. The eucalyptus wood has its principal use in the paper and cellulose industry. However, abiotic and biotic factors affect the expansion of forest plantation. Water availability is the major limitation to development of species affecting biomass production. The plant hormone abscisic acid (ABA) triggers resistance responses to abiotic stresses, in particular to drought. The objective of this study was to identify Single Nucleotide Polymorphism (SNPs) in nine-cis-epoxycarotenoid dioxygenase (NCED), enzyme of ABA biosynthetic pathway, in Eucalyptus. Through the utilization of amino acid sequence of this enzyme of Arabidopsis (AtNCED3) and using availability Expressed Sequence Tags (ESTs) database of Eucalyptus, as possible the development of three PCR primers that amplified the desirable regions of the gene. Thus, specifics primers were designed and amplification products of different individuals submitted to direct sequencing. The alignment and analysis of sequences revealed the occurence of seven SNPs in NCED gene, in a region of 1230 base pairs. The rate of transition/transversion was 1.33. After the prediction of protein, by the sites Softberry and Expasy, it was verified five SNPs, in coding region, that generated synonymous substitutions. Using the DnaSP program, seven haplotypes were found in a sample of 65 individuals, consisting of the species E. grandis, E. urophylla and the hybrid Urograndis. For these seven polymorphic sites were designed SNPs markers sets that will allow large-scale genotyping for population genetic studies and assisted breeding programs
20

Impacto dos haplÃtipos do gene ΒS sobre os marcadores de hemÃlise em pacientes com anemia falciforme em estado basal / THE IMPACT OF THE ΒS GENE HAPLOTYPES ON THE MARKERS OF HEMOLYSIS IN ADULT PATIENTS WITH SICKLE CELL ANEMIA AT BASELINE.

Juliane Almeida Moreira 28 February 2013 (has links)
CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior / A anemia falciforme (AF) Ã uma doenÃa hereditÃria resultante de uma mutaÃÃo pontual (GAG &#61664; GTG) no cÃdon do gene da &#946;S - globina, levando a uma substituiÃÃo de Ãcido glutÃmico por valina na sexta posiÃÃo da cadeia polipeptÃdica, gerando uma hemoglobina (Hb) anormal denominada de HbS, em homozigose. A AF se caracteriza por anemia hemolÃtica crÃnica associada a mÃltiplos eventos tais como processo inflamatÃrio crÃnico, aumento do estresse oxidativo, dano endotelial, diminuiÃÃo da biodisponibilidade do Ãxido nÃtrico (NO), ativaÃÃo da coagulaÃÃo, dentre outros. Os biomarcadores de hemÃlise tais como: contagem de reticulÃcitos, lactato desidrogenase (LDH), Ãcido Ãrico e arginase I sÃo fundamentais na avaliaÃÃo do grau da hemÃlise, principalmente, de natureza intravascular contribuindo com o monitoramento da anemia nesses pacientes. O presente estudo teve como objetivo avaliar o impacto dos haplÃtipos do gene &#946;S sobre os marcadores de hemÃlise em adultos com AF em estado basal, acompanhados no ambulatÃrio do serviÃo de hematologia no Hospital UniversitÃrio Walter CantÃdio (HUWC). Um total de 50 pacientes adultos com AF foi selecionado, com diagnÃstico confirmado por estudo molecular. Os pacientes se encontravam em uso de hidroxiurÃia (HU), dose variando de 500 mg a 1,5 g/kg/dia por no mÃnimo seis meses. Um grupo controle foi elaborado, sendo constituÃdo por 20 indivÃduos supostamente saudÃveis. Foram coletados 10 mL de sangue venoso em tubo de coleta a vÃcuo, contendo o anticoagulante EDTA (etileno-diamino-tetracÃtico), para a realizaÃÃo da contagem de reticulÃcitos e 6 mL de sangue venoso em tubo de coleta a vÃcuo contendo gel separador, sem anticoagulante, para as dosagens sÃricas de LDH , Ãcido Ãrico e arginase I. As variÃveis idade, sexo, dosagem e tempo de uso do medicamento, concentraÃÃo da Hb e da hemoglobina fetal (HbF) foram obtidas nos prontuÃrios mÃdicos no momento da realizaÃÃo do estudo. As anÃlises estatÃsticas foram realizadas no programa GraphPad Prism (versÃo 5.0) e o nÃvel de significÃncia estabelecido foi p < 0,05. Foi verificado aumento significante nos nÃveis de reticulÃcitos, LDH, Ãcido Ãrico e arginase I nos pacientes com AF em relaÃÃo ao grupo controle (p < 0,05). Foi observada diferenÃa significativa na Hb nos grupos Bantu/Benin em relaÃÃo aos demais haplÃtipos do cluster da &#946;s-globina. Os nÃveis de HbF apresentaram uma tendÃncia a aumento no haplÃtipo Benin/Benin em relaÃÃo aos demais. Foi verificada uma tendÃncia no aumento de LDH no genÃtipo Bantu/Bantu em comparaÃÃo com os demais haplÃtipos. Foi observada diferenÃa significativa da arginase I entre os grupos Bantu/Bantu vs Bantu/Benin e Bantu/Bantu vs Benin/Benin. Os resultados do presente estudo reforÃam a hipÃtese de que a arginase I possa ser utilizada como possÃvel indicador de gravidade uma vez que a mesma foi associada ao haplÃtipo Bantu.

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