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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.
41

Etude de la dynamique de l'expression de la molécule HLA-G, en contexte sain et pathologique, en fonction du génotype HLA et de facteurs externes / Study of the expression feature of HLA-G molecule, in healthy and pathological context, depending on the HLA genotype and external factors

Carlini, Federico 27 October 2016 (has links)
Les molécules HLA de class Ib ou nonclassiques, HLA-G, -E et -F, sont impliqués dans la régulation de la tolérance immunologique. En particulier, les polymorphismes génétiques ainsi que l’expression différentielle de HLA-G sont corrélés à l’évolution clinique des pathologies inflammatoires et des greffes d’organe. Notre premier travail a permis de montrer que la structure génétique de HLA-G était conservée dans des populations au patrimoine génétique différent (Mali et Sud de la France) et que, les haplotypes résultants (UTR), étaient corrélés à l’expression différentielle d’HLA-G soluble. Dans une deuxième étude on a pu montrer l’association différentielle des haplotypes HLA-G UTR avec certain allèles HLA-E, -A, -H, -G et -F suggérant une interaction privilégiée et/ou un effet tolérant synergique entre ces molécules. Une troisième étude a mis en évidence que deux haplotypes HLA-G UTR étaient corrélé à une évolution clinique péjorative dans la mucoviscidose et dans la transplantation pulmonaire. En fin, on a pu montrer une expression différentielle des isoformes de HLA-G dans les cellules épithéliales bronchiques (CEB), redifférencié in vitro, de témoins sains et patients atteints d’asthme avec une expression diminuée chez les asthmatiques. Finalement, l’ensemble de ces données suggèrent que la molécule HLA-G peut être un biomarqueur génétique et/ou sérologique attrayant et une cible thérapeutique potentielle via la modulation de son effet tolérogène dans un contexte de pathologies inflammatoires ou de conflit immunologique, tel que la transplantation d’organe et la transfusion. / HLA nonclassical class Ib genes HLA-G, -E and -F are involved in managing immune tolerance. Particularly for HLA-G, both its genetic polymorphism and its expression are correlated to clinical outcome in different pathologies, particularly in inflammatory disease and organ transplantation. In our first work we have shown that HLA-G genetic structure was conserved in distant healthy populations (Mali and South France) and that, the resulting haplotypes (UTR) were correlated to sHLA-G differential expression. In another study we observed a differential association between HLA-G UTR haplotypes and specific HLA-E, -A, -H, -F alleles that might reflect a privileged interaction and/or a synergistic tolerant effect between these molecules In a third study we showed that two different HLA UTR haplotypes were respectively associated with a worse evolution of cystic fibrosis and an impaired survival in lung transplant recipients. Afterwards, the analysis HLA-G isoforms expression in normal, mild and severe asthmatic human bronchial epithelial cells redifferentiated in vitro showed that the level of these transcripts was significantly reduced in asthmatics compared to controls. In conclusion, these results suggest that HLA-G molecule might be an attractive genetic and/or serologic biomarker and a potential therapeutic target, via the modulation of its tolerogenic effect, in specific allogenic and inflammatory contexts, such as solid organ transplantation or blood transfusion.
42

DNA barcoding of different earthworms' species and their response to ecotoxicological testing / Laetitia Voua Otomo

Voua Otomo, Laetitia January 2015 (has links)
The ecotoxicological literature reveals that countless researchers worldwide rely upon informally identified commercial earthworm stocks for laboratory bioassays. The primary aim of this study was to investigate laboratory and commercial stocks of Eisenia species used in South Africa in order to confirm their taxonomy, assess their levels of genetic richness and differentiation. To do so, populations of potential Eisenia andrei and Eisenia fetida were purchased/obtained from vermiculturists and laboratories from four provinces of South Africa. DNA barcoding was used to investigate these taxonomic uncertainties. The COI gene was partially amplified and sequenced in selected earthworms from eight local populations (focal groups) and two European laboratory stocks (non-focal groups). Only nine COI haplotypes were identified from the 224 sequences generated. One of these haplotypes was found to belong to the Megascolecidae Perionyx excavatus. The remaining eight haplotypes belonged to the genus Eisenia although only a single Eisenia fetida haplotype, represented by six specimens, was found in one of the European populations. The other seven haplotypes, all occurring in South Africa, were Eisenia andrei. No Eisenia fetida was found in the South African based populations. One of the commercial stocks from South Africa and a laboratory culture from Europe were mixes of E. andrei - P. excavatus and E. andrei – E. fetida respectively. COI haplotype numbers were limited to two to three distinct sequences within each of the local groups. This translated into a haplotype diversity (H) lower than 0.45 in all the populations, which is very low when compared to other such earthworm studies in which COI polymorphism has been investigated. Of all the local populations investigated, only the lone field population included was genetically divergent from the other populations. This was explained by the haplotype distribution across the populations which indicated that this population was the only one not harbouring the haplotype which represented 75% or more of the COI sequences within the local populations. Because research suggests that earthworm populations with limited genetic diversity may suffer inbreeding depression which could affect traits such as reproduction and survival, the secondary aim was to test whether metal-sensitive earthworms were overly present in the populations investigated. To do so, the three most common COI haplotypes identified between the 8 local populations of E. andrei (called Hap1, Hap2 and Hap3) were paired up and exposed to cadmium. A total of six couples were exposed to 0, 25, 50 and 100 mg Cd/kg for 4 weeks at 20ºC. The survival, biomass variation, cocoon production and cocoon hatching success were assessed for all the couples. The results indicated that couple 6 (Hap3xHap3) was the most sensitive for three of the endpoints assessed whereas couple 4 (Hap1 x Hap3) was the least sensitive. Cocoon hatching success could not help differentiate the couples. The analysis of Cd tissue contents revealed that with increasing Cd concentration, Cp6 (Hap3xHap3) could accumulate significantly more Cd than any other couple (p ≤ 0.01). These findings indicate that earthworm populations may carry intrinsically metal-tolerant and metal-sensitive genotypes. In the context of ecotoxicological testing, the present results underline the importance of using genetically diverse populations in laboratory testing as Cp6 (Hap3xHap3) could have suffered from the deleterious effect of inbreeding. Because E. fetida could not be found in the local populations assessed, it is recommended that further earthworm DNA barcoding studies, covering a more representative geographical area of South Africa and including more field populations of Eisenia spp. be conducted. Because of the occurrence of genetic homogeneity in the populations studied, it is suggested that captive breeding initiatives be established using specimens obtained from several geographically distant field and reared populations. Further research investigating patterns of Cd accumulation/excretion kinetics between the Cd-tolerant and Cd-sensitive individuals reported in the present study, should be conducted to help determine whether inbreeding is the sole factor explaining the observed genotypic responses to Cd. Finally, the necessity of a standardised earthworm barcoding protocol that could help both to properly identify laboratory earthworm stocks and to select genetically diverse stocks suitable for laboratory testing, is discussed together with the relevance of the present work to ecotoxicological testing in general. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2015
43

DNA barcoding of different earthworms' species and their response to ecotoxicological testing / Laetitia Voua Otomo

Voua Otomo, Laetitia January 2015 (has links)
The ecotoxicological literature reveals that countless researchers worldwide rely upon informally identified commercial earthworm stocks for laboratory bioassays. The primary aim of this study was to investigate laboratory and commercial stocks of Eisenia species used in South Africa in order to confirm their taxonomy, assess their levels of genetic richness and differentiation. To do so, populations of potential Eisenia andrei and Eisenia fetida were purchased/obtained from vermiculturists and laboratories from four provinces of South Africa. DNA barcoding was used to investigate these taxonomic uncertainties. The COI gene was partially amplified and sequenced in selected earthworms from eight local populations (focal groups) and two European laboratory stocks (non-focal groups). Only nine COI haplotypes were identified from the 224 sequences generated. One of these haplotypes was found to belong to the Megascolecidae Perionyx excavatus. The remaining eight haplotypes belonged to the genus Eisenia although only a single Eisenia fetida haplotype, represented by six specimens, was found in one of the European populations. The other seven haplotypes, all occurring in South Africa, were Eisenia andrei. No Eisenia fetida was found in the South African based populations. One of the commercial stocks from South Africa and a laboratory culture from Europe were mixes of E. andrei - P. excavatus and E. andrei – E. fetida respectively. COI haplotype numbers were limited to two to three distinct sequences within each of the local groups. This translated into a haplotype diversity (H) lower than 0.45 in all the populations, which is very low when compared to other such earthworm studies in which COI polymorphism has been investigated. Of all the local populations investigated, only the lone field population included was genetically divergent from the other populations. This was explained by the haplotype distribution across the populations which indicated that this population was the only one not harbouring the haplotype which represented 75% or more of the COI sequences within the local populations. Because research suggests that earthworm populations with limited genetic diversity may suffer inbreeding depression which could affect traits such as reproduction and survival, the secondary aim was to test whether metal-sensitive earthworms were overly present in the populations investigated. To do so, the three most common COI haplotypes identified between the 8 local populations of E. andrei (called Hap1, Hap2 and Hap3) were paired up and exposed to cadmium. A total of six couples were exposed to 0, 25, 50 and 100 mg Cd/kg for 4 weeks at 20ºC. The survival, biomass variation, cocoon production and cocoon hatching success were assessed for all the couples. The results indicated that couple 6 (Hap3xHap3) was the most sensitive for three of the endpoints assessed whereas couple 4 (Hap1 x Hap3) was the least sensitive. Cocoon hatching success could not help differentiate the couples. The analysis of Cd tissue contents revealed that with increasing Cd concentration, Cp6 (Hap3xHap3) could accumulate significantly more Cd than any other couple (p ≤ 0.01). These findings indicate that earthworm populations may carry intrinsically metal-tolerant and metal-sensitive genotypes. In the context of ecotoxicological testing, the present results underline the importance of using genetically diverse populations in laboratory testing as Cp6 (Hap3xHap3) could have suffered from the deleterious effect of inbreeding. Because E. fetida could not be found in the local populations assessed, it is recommended that further earthworm DNA barcoding studies, covering a more representative geographical area of South Africa and including more field populations of Eisenia spp. be conducted. Because of the occurrence of genetic homogeneity in the populations studied, it is suggested that captive breeding initiatives be established using specimens obtained from several geographically distant field and reared populations. Further research investigating patterns of Cd accumulation/excretion kinetics between the Cd-tolerant and Cd-sensitive individuals reported in the present study, should be conducted to help determine whether inbreeding is the sole factor explaining the observed genotypic responses to Cd. Finally, the necessity of a standardised earthworm barcoding protocol that could help both to properly identify laboratory earthworm stocks and to select genetically diverse stocks suitable for laboratory testing, is discussed together with the relevance of the present work to ecotoxicological testing in general. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2015
44

Déséquilibre de liaison et cartographie de QTL en population sélectionnée

Ytournel, Florence 28 January 2008 (has links) (PDF)
Par définition le déséquilibre de liaison (Linkage Disequilibrium, LD) décrit les associations préférentielles entre allèles de deux locus. Ce concept est devenu un outil indispensable pour la cartographie fine de locus quantitatifs (QTL), par l'identification de déséquilibres d'associations entre allèles à un locus marqueur (ou à un ensemble de locus marqueurs) et à un locus impliqué dans la variation d'un caractère quantitatif. La création et l'intensité du LD sont dépendantes des forces évolutives qui ont construit la population. Parmi ces forces, la dérive génétique et la sélection sont particulièrement actives dans les populations d'animaux de rente. Cette thèse a pour but d'étudier l'influence de la sélection sur la structure du déséquilibre de liaison autour d'un locus quantitatif, ainsi que son impact sur la précision de cartographie fine des QTL. Un logiciel de simulation de populations a été développé dans le cadre de la thèse. A partir d'une population en équilibre de liaison, il permet de générer du LD dans des générations dites historiques, grâce à différentes forces évolutives. La détection de QTL est appliquée aux générations suivantes, de généalogie connue. Pour ces dernières générations, les principaux dispositifs de détection de QTL de génétique animale sont décrits dans le simulateur. Les données exploitées dans cette thèse sont issues de ce logiciel. Le LD a été mesuré par le D' et le
45

Étude d'association entre l'asthme et le gène plasminogen activator, urokinase dans la population du Saguenay-Lac-Saint-Jean

Bégin, Philippe January 2008 (has links)
Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.
46

Detecção de QTL para maciez da carne em bovinos da raça Nelore /

Braz, Camila Urbano. January 2016 (has links)
Orientador: Henrique Nunes de Oliveira / Banca: Maria Eugênia Zerlotti Mercadante / Banca: Ricardo Vieira Ventura / Banca: Fernando Sebastian Baldi Rey / Banca: Nedenia Bonvino Stafuzza / Resumo: O mercado consumidor tem sido cada vez mais exigente quanto à qualidade da carne e, portanto, a pecuária precisa melhorar sua eficiência e fornecer produtos diferenciados, padronizados e com qualidade. Entre as características de qualidade de carne, a maciez é a que mais influencia na satisfação dos consumidores. Considerando a importância dada à maciez da carne, pesquisas têm sido desenvolvidas para melhor compreender os mecanismos relacionados à expressão fenotípica desta característica. Os estudos de genes candidatos têm possibilitado a identificação de polimorfismos que modificam as estruturas das proteínas ou ainda, que estejam em desequilíbrio de ligação com alterações funcionais no DNA. Com a automatização dos polimorfismos de nucleotídeo único (SNPs) muitas regiões ao longo do genoma foram identificadas como responsáveis pela variação fenotípica da maciez da carne. No entanto, os marcadores SNPs podem ter baixa capacidade de identificar locos que atuam nas características quantitativas (QTL) por serem, na grande maioria, bi-alélicos e, mesmo que aconteçam mutações, as mudanças nas frequências alélicas dos SNPs podem permanecer quase inalteradas. Por outro lado, com a utilização de haplótipos, mutações tendem a causar mudanças nas frequências dos haplótipos, aumentando as chances de identificação dos QTL. Sendo assim, este estudo teve como objetivos detectar QTL e mutações causais em genes candidatos e identificar QTL por meio de uma análise de associação genômica ampl... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The consumer market has been increasingly demanding about the meat quality and therefore livestock needs to improve its efficiency and provide differentiated products, standardized and with quality. Considering the importance given to the meat tenderness, research has been undertaken to better understand the mechanisms related to the phenotypic expression of this trait. The candidate gene studies have allowed the identification of polymorphisms that change the structures of the proteins or that are in linkage disequilibrium with functional alterations in the DNA. With the advent of single nucleotide polymorphisms (SNPs) throughout many regions of the genome have been identified as responsible for phenotypic variation in meat tenderness. However, SNPs markers may have low ability to identify mutations, because SNPs are commonly bi-allelic and even when mutations have occurred, allelic frequencies can remain unaltered. On the other hand, using haplotype, mutations tend to cause major changes in haplotype frequencies, increasing the chances of identification of QTL. Thus, this study aimed to detect QTL and causal mutations by the approach of candidate genes and identify possible QTL through a genome-wide association analysis, for the trait meat tenderness in Nelore cattle using haplotypes as fundamental units of association tests. Information of the phenotypic, genotypic and pedigree were used from farms that belong to the breeding programs DeltaGen and PAINT. Fifty-two candidat... (Complete abstract click electronic access below) / Doutor
47

Phylogeographic patterns and migration history of Garry oak (Quercus garryana) in western North America

Kanne, Rande 19 August 2019 (has links)
Garry oak (Quercus garryana Douglas ex. Hook) is a white oak (Quercus sect. Quercus) with a geographic range extending from southwestern BC to south-central California. It is the only native white oak in BC and Washington, and is the northernmost species of the California Floristic Province-Pacific Northwest white oak clade. I used molecular methods to address the following questions: 1) What are the patterns of genetic variation within Garry oak? 2) How do these patterns vary geographically, and how did the spatial distribution of the gene lineages come to occupy its current geographical range? 3) Does Garry oak show evidence of genetic interaction with other white oak species in western North America? 4) Is there morphological or genetic evidence to support the three described varieties of Garry oak? I obtained samples of Garry oak from 117 localities over its geographic range, as well as samples of two other California white oaks (Q. lobata and Q. douglasii) and a Rocky Mountain species (Q. gambelii). Analyses of DNA sequence data from four plastid DNA regions revealed 24 distinct molecular variants (haplotypes) in Garry oak. These show a strong south-to-north decrease in genetic diversity, consistent with post-glacial northward expansion. Haplotypes present in the northern part of the range provide evidence of two separate northward migrations, only one of which reached the northern range limit of Garry oak in BC. I found that Garry oak shared plastid DNA haplotypes with two other white oak species, indicating that it hybridizes with other oaks in the southern part of its range. The nuclear ribosomal ITS phylogeny showed poor resolution, but both cpDNA and nrDNA may indicate that Q. garryana is more closely related to the white oaks of central North America than was previously thought. My findings also suggest that the three currently recognized varieties of Garry oak (var. garryana, breweri and semota) are not well differentiated genetically, but show morphological variation at the regional level. This study shows the phylogeographic patterns within Q. garryana. In addition, it contributes to conservation efforts in Garry oak ecosystems by indicating regions of high genetic diversity in Garry oak, including genetically unique populations that may be especially worthy of preservation. / Graduate
48

Assinaturas de seleção em três linhas de bovinos Nelore selecionados para características de crescimento /

Cardoso, Diércles Francisco. January 2016 (has links)
Orientador: Humberto Tonhati / Coorientador: Fernando Sebastián Baldi Rey / Coorientador: Maria Eugênia Zerlotti Mercadante / Coorientador: Henner Simianer / Banca: Fábio Ricardo pablos de Souza / Banca: Lucia Galvão de Albuquerque / Banca: Joslaine Noely dos Santos Gonçalves Cyrillo / Banca: Marcos Eli Buzanskas / Resumo: Análises de assinaturas de seleção são ferramentas úteis para identificação de padrões genômicos estabelecidos devido às interações humanas com animais domésticos. Em algumas situações, a estratificação dentro de uma raça permite a comparações genômicas entre subpopulações para elucidar assinaturas de seleção. O presente estudo teve o objetivo de analisar a estratificação existente em uma população experimental de bovinos da raça Nelore com três linhas de seleção e revelar assinaturas de seleção pertinentes à seleção direcional para aumento no peso ao sobreano. Para estes fins, foram utilizados animais genotipados com o painel de alta densidade de SNPs (Illumina® BovineHD beadchip - 777K), sendo 674 animais pertencentes à duas linhas mantidas sob seleção direcional para aumento do peso ao sobreano e 89 animais pertencentes a uma linha mantida sob seleção estabilizadora, baseada na mesma característica. A estratificação populacional foi avaliada pela análise de escalonamento multidimensional da matriz de distâncias genômicas e também pela análise da ancestralidade individual estimada a partir da matriz de marcadores. As assinaturas de seleção foram avaliadas com três métodos complementares, o índice de fixação de Wright (FST), a homozigose do haplótipo estendido entre populações (XP-EHH) e o escore de integração dos haplótipos (iHS). As diferentes abordagens utilizadas na avaliação da estrutura de populações apresentaram elevada consistência, revelando separação da população e... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Analyses of selection signatures are valuable tools to identify genomic patterns formed by the interaction between humans and domestic animals. In some situations, the within-breed stratification enables genomic comparisons between groups of the same breed in order to study genetic mechanisms underlying given phenotypes under selection. The current study aimed to analyze the genomic stratification in an experimental population of Nellore cattle that keeps three selection lines, and highlight selection signatures pertinent to the practiced directional selection. To this end, was used a sample of animals genotyped with high density SNPs panel (Illumina® BovineHD beadchip - 777K), being 674 animals from two lines kept under directional selection for higher yearling body weight and 89 animals from one line kept under stabilizing selection based on the same trait. The population structure was assessed with multidimensional analysis based on the genomic distances matrix and with Admixture analyses based on genotype matrix. Selection signatures scans were based on three complementary methods the Wright's fixation index (FST), Cross Population Extended Haplotype Homozygosity (XP-EHH) and the integrated Haplotype score (iHS). The different approaches used in order to assess the population structure were largely consistent, revealing the population separation in three clusters equivalent to the three selection lines. The line under stabilizing selection was represented by an isolated c... (Complete abstract click electronic access below) / Doutor
49

Variabilidade genética e estrutura haplotípica do gene kir2dl4 avaliada em uma amostra brasileira

Weiss, Emiliana January 2019 (has links)
Orientador: Erick da Cruz Castelli / Resumo: O gene KIR2DL4 codifica um importante receptor de células Natural Killer (NK). O único ligante de KIR2DL4 conhecido é a molécula HLA-G, expressa principalmente na placenta, modulando a ação das células NK durante a gestação. O gene KIR2DL4 parece ser bastante variável, quando considerado os bancos de dados que armazenam suas sequências conhecidas, porém não está claro o nível de diversidade deste gene em populações reais e heterogêneas. Polimorfismos presentes no gene KIR2DL4 poderiam influenciar a interação entre KIR2DL4 e HLA-G, modificando a ação das células NK. Neste estudo exploramos a variabilidade genética de KIR2DL4 em 157 indivíduos oriundos do Estado de São Paulo/Brasil. Devido à alta similaridade de sequências entre os genes KIR, erros de genotipagem são esperados quando se utiliza sequenciamento de segunda geração. Por este motivo, desenvolvemos uma abordagem para classificar cada leitura com base em sequências KIR conhecidas, endereçando-as ao gene mais provável. Também utilizamos o painel SNPforID 34-plex para avaliar a ancestralidade dessas amostras. Considerando o segmento completo desse gene, indo da região 5’URR até a 3’UTR, com aproximadamente 13kb, o gene KIR2DL4 se mostrou pouco polimórfico, com 152 pontos de variações identificados (MAF 1%). Esses pontos de variação estão organizados em 32 haplótipos estendidos que codificam 13 proteínas diferentes. Foram encontrados 11 haplótipos na região promotora, sendo que 8 possuem MAF maior que 1%. Na região codif... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: KIR2DL4 is the most unusual Killer Cell Immunoglobulin-Like receptor (KIR) family member in terms of structure, expression, and signaling properties. The only known KIR2DL4 ligand is HLA-G, and polymorphisms might disrupt this interaction. KIR2DL4 variability is not well explored in admixed populations. Here we explored KIR2DL4 exon variability in 157 individuals from the State of São Paulo/Brazil. Because of sequence similarity with other KIR genes, it is expected genotyping errors when using secondgeneration sequencing. We developed an approach to score each read based on known KIR sequences, addressing them to the most likely locus. We evaluated the SNPforID 34-plex panel to assess ancestry. The methodology was applied to survey the variability of a very admixed population, such as Brazilian, counting with 157 samples of São Paulo State. Considering a segment of about 13-kb, KIR2DL4 gene was conserved with few different and frequent sequences. Overall, 152 variable sites were detected, arranged in 32 haplotypes codifying 13 protein. We found 11 promoter haplotypes, 8 with a frequency greater than 1%. In the coding region we detected 70 haplotypes, four of which correspond to 50% of the coding sequences (KIR2DL4 * 0080204, * 008105, * 001, * 005). In the 3'UTR region, 14 haplotypes were identified with MAF greater than 1%. The KIR2DL4 coding region was the most variable segment. We observed that KIR2DL4 variability is strongly influenced by the sample ancestry background. K... (Complete abstract click electronic access below) / Mestre
50

DNA antigo de amostras de ossos de baleia-franca-austral, Eubalaena australis (Desmoulins, 1822) (Mysticeti, Cetartiodactyla) no Atlântico Sul Ocidental

Gasperin, Débora Stefani 30 September 2014 (has links)
Submitted by William Justo Figueiro (williamjf) on 2015-07-06T23:37:20Z No. of bitstreams: 1 10a.pdf: 1719495 bytes, checksum: 2ed1add8423e889edf7e44b9eb1498f1 (MD5) / Made available in DSpace on 2015-07-06T23:37:20Z (GMT). No. of bitstreams: 1 10a.pdf: 1719495 bytes, checksum: 2ed1add8423e889edf7e44b9eb1498f1 (MD5) Previous issue date: 2014-07 / Nenhuma / A baleia-franca-austral (Eubalaena australis) foi alvo de grande exploração comercial entre os séculos XVII a XX no Hemisfério Sul. Estimativas recentes sugerem que a população mundial da espécie é de 12.000 indivíduos, o que representaria 17 a 21% do seu tamanho original. Apesar de aparente recuperação, o declínio drástico no tamanho da população, resultante dos 400 anos de atividade da caça, pode ter gerado altos níveis de endogamia, baixa capacidade reprodutiva e perda de variabilidade genética da espécie, podendo ter seu potencial adaptativo comprometido, aumentando assim a probabilidade de extinção. Frente ao exposto é de extrema importância a avaliação comparativa da variabilidade genética entre as populações atuais de E. australis e amostras representativas do período de caça, em especial no Brasil. Sendo assim, os objetivos deste estudo foram: I. Otimizar e comparar métodos de extração e amplificação de DNA antigo (aDNA) de ossos de baleia-franca-austral, em diferentes estados de degradação; II. Caracterizar geneticamente segmentos da região D-Loop do DNA mitocondrial (mtDNA) a partir de ossos de espécimes de E. australis coletados na Península Valdés na Argentina e em Santa Catarina no Brasil; e III. Comparar as sequências nucleotídicas da região recuperada nas amostras de aDNA com as descritas para as populações atuais. Este estudo comparou cinco métodos diferentes para obter material genético de amostras degradadas. O método de extração que mostrou ser mais eficiente foi o que continha o reagente Dextran Blue. Com a amplificação de 20 fragmentos curtos, obtidos pelo Nested-PCR, com clonagem e posterior sequenciamento, foi possível recuperar pequenos fragmentos, que variaram de 7 a 59 pb, da região D-Loop do mtDNA de 11 amostras de ossos de E. australis das 88 tentativas realizadas. Ao analisar o material recuperado com dados atuais da espécie, o programa Network 4.6 revelou uma rede contendo 19 haplótipos, sendo quatro haplótipos restritos as populações antigas e até então não descritos na literatura. Os resultados são preliminares e seus significados devem ser avaliados com muita cautela. Contudo, deve-se ressaltar que os quatro novos haplótipos encontrados podem sustentar a hipótese de uma maior diversidade haplotípica em E. australis quando a mesma era caçada comercialmente. / The Southern Right Whale (Eubalaena australis) was object of great commercial exploitation between the XVII and XX centuries in the Southern Hemisphere. Recent surveys suggest that the world’s population is of 12,000 specimens, which would represent 17% to 21% of its original size. Despite the supposed recovery, the drastic populational decline, resultant from 400 years of hunting activities, could have generated high levels of endogamy, low reproduction capacity and loss of genetic variability of the species, compromising their potential of adjustment, thus increasing their probability of extinction. Due to the exposed, it is of extreme importance the comparative evaluation of the genetic variability between the current E. australis population and representative samples from the hunting period, especially from Brazilian coast. Therefore, the purpose of this study was: I. To optimize and compare extraction and amplification methods of aDNA from Southern Right Whale’s bones in different stages of deterioration; II. To genetically characterize segments of the mtDNA’s D-Loop region from E. australis bones collected at Península Valdés in Argentina and Santa Catarina in Brazil, and III. To compare nucleotide sequences of the recovered region from aDNA samples with those described for the current populations. This study compared five different extraction methods in order to obtain genetic material from deteriorated samples. The extraction method containing Dextran Blue reagent showed the higher efficiency. With the amplification of 20 short fragments and overlapping of aDNA through Nested-PCR technique, and further cloning of the latter fragment, it was possible to sequence small fragments, varying from 7 to 59 pb, from the mtDNA’s D-loop region from 11 bones samples of E. australis, out of the 88 attempts performed. Analyzing the recovered material together with the updated data of the species, the Network 4.6 program revealed a network containing 19 haplotypes, 4 of them generated only with ancient population samples, which are new for the species. The results are still preliminary and their meanings should be evaluated with caution. However, it should be noted that the four new haplotypes found could support the hypothesis of a higher haplotype diversity in E. australis when it was hunted.

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