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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.
81

Population Genetics of Hudson Bay Beluga Whales (Delphinapterus leucas): An Analysis of Population Structure and Gene Flow using Mitochondrial DNA Sequences and Multilocus DNA Fingerprinting / Population Genetics of Hudson Bay Beluga Whales

Mancuso, Samuel 09 1900 (has links)
Beluga whales in Canadian waters are subdivided into at least six genetically distinct stocks maintained by geographic separation and philopatry to estuaries in summer. Belugas in eastern and western Hudson Bay have previously been shown to be compose genetically distinct populations using mitochondrial restriction analysis. It is not known whether these stocks are further subdivided on the basis of specific estuarine use. Mitochondrial DNA control region sequences were used to investigate variation among belugas sampled at several sites along eastern Hudson Bay, Hudson Strait and Ungava Bay. 320 bp were sequenced, including the highly variable 5' region of control region, in 126 belugas. 17 variable sites and 17 haplotypes, which clustered into 2 related groups, were detected among the whales sequenced. Haplotypes of group A were found mostly in eastern Hudson Bay sites, while B group haplotypes were predominant in northern populations. Significant differences in frequencies of haplotype groups were found between eastern Hudson Bay and Southern Hudson Strait/Ungava Bay populations, indicating they are genetically distinct populations. Haplotype distribution patterns also suggested possible differences between belugas using different estuaries along eastern Hudson Bay. The presence of both groups in each population indicated some exchange of individuals between populations, and/or between eastern and western Hudson Bay. Multilocus DNA fingerprinting was used to investigate the extent of gene flow between eastern and western Hudson Bay belugas via interbreeding on common wintering grounds in Hudson Strait. Belugas from St. Lawrence estuary and the Mackenzie Delta were also analyzed to measure their genetic relatedness to Hudson Bay whales as well as for purposes of comparison to earlier fingerprinting analyses. While results supported lower genetic diversity within the St. Lawrence population, the range of bandsharing within and between populations was otherwise low (0.09 -0.17 for Jeffreys 33.15 and 0.12-0.22 for Jeffreys 33.6). Mantel tests showed differences among St. Lawrence, Hudson Bay, and Mackenzie Delta populations, but not within Hudson Bay. The conflicting nature of the data did not allow conclusions regarding gene flow. Therefore, DNA fingerprinting was not considered to have provided sufficient resolution in addressing this issue. / Thesis / Master of Science (MS)
82

Genetic variation of Aspergillus fumigatus from Auckland, New Zealand / Contemporary gene flow is a major force shaping the Aspergillus fumigatus population in Auckland, New Zealand

Korfanty, Gregory January 2019 (has links)
Aspergillus fumigatus is a globally present opportunistic fungal pathogen that plays a key role in degrading organic matter. A. fumigatus can cause a vast array of diseases, collectively known as aspergilloses. The most serious of these is invasive aspergillosis, that has a mortality rate of 30 to 95% with treatment. Recent studies have indicated that the global A. fumigatus population consists of multiple divergent genetic clusters that are broadly distributed geographically. However, most of the previously analyzed samples have come from continental Eurasia and the Americas where the effects of historical or contemporary gene flow is difficult to distinguish. My thesis project, therefore, focused on analyzing the genetic diversity of the Auckland, New Zealand A. fumigatus population, as it is geographic distant from all previously analyzed populations. Here, we obtained 104 A. fumigatus isolates from Auckland and compared the genotypes of these isolates to population data obtained from nine other countries from Europe, Africa, North America, and Asia. The goal was to analyze the potential effects of historical differentiation and gene flow within this population. We determined that the Auckland population had a low, non-significant level of differentiation compared to most previously surveyed global populations. However, the Auckland population also contained unique genetic elements not present within populations from other geographic regions. Though the hypothesis of random recombination was rejected, we found abundant evidence for phylogenetic incompatibility and recombination within the Auckland A. fumigatus population. Lastly, we identified two triazole resistant strains within the Auckland population, with one carrying the common TR34/L98H cyp51A mutation. Our results suggest that contemporary gene flow, likely due to anthropogenic factors, is a major force shaping the New Zealand A. fumigatus population. These results contribute to our understanding of the high levels of gene flow observed within and among many geographic populations of A. fumigatus. / Thesis / Master of Science (MSc) / Aspergillus fumigatus is a globally distributed fungal mold capable of causing serious diseases in individuals with weakened immune systems or lung damage. In the environment, A. fumigatus lives in the soil where it degrades organic matter and contributes to the cycling of nitrogen and carbon across the planet. Due to the airborne nature of its spores, people inhale this fungus daily, and those at risk may develop disease. These diseases, collectively known as aspergilloses, can result in long term chronic illnesses, and in the case of invasive aspergillosis, the death rate can be as high as 95%, even with treatment. Medical treatment of aspergilloses involves the use of antifungal drugs. However, some A. fumigatus strains have developed resistance. I am interested in the patterns of global genetic diversity of A. fumigatus populations. For my MSc thesis, I investigated the A. fumigatus population within Auckland, New Zealand, as it is both geographically isolated and distant from other previously surveyed populations. Our data illustrated that the New Zealand population contains pockets of unique diversity as well as high levels of similarity to the previously surveyed populations within Europe. My results suggest that human influences, likely due to travel and trade, have played a large role in shaping the genetic diversity of the A. fumigatus population from Auckland, New Zealand.
83

Noninvasive tracking of jaguars (Panthera onca) and co-occurring Neotropical felids in Belize, Central America by genotyping feces and remote camera trapping

Wultsch, Claudia 30 April 2013 (has links)
The elusive jaguar (Panthera onca) is extremely difficult to study due to its wide-ranging behavior, crepuscular activity peaks and its occurrence in low population densities in often dense forest habitats. Jaguars are also a species of concern, but our ability to provide for their survival is hampered by our inability to obtain reliable information on the status of their wild populations. This study combines innovative noninvasive research techniques such as scat detector dogs and molecular scatology to conduct the first genetic study on wild populations of Neotropical felids coexisting across fragmented forest habitats in Belize, Central America. Specifically, we analyzed multi-locus data in jaguars (Panthera onca), pumas (Puma concolor) and ocelots (Leopardus pardalis) collected from 1053 scat samples across their range in the country. First, we optimized 14 polymorphic microsatellite loci for jaguars (Panthera onca), pumas (Puma concolor), and ocelots (Leopardus pardalis), and assessed their utility for cross-species amplification. Additionally, we tested their reliability for species and individual identification using fecal DNA as he primary DNA source. All microsatellite loci examined successfully cross-amplified in the three target species, and were polymorphic. Second, to maximize PCR amplification success and genotyping accuracy rates, and to minimize genotyping error rates for fecal DNA samples, we evaluated the performance of two fecal DNA storage techniques (dimethyl sulfoxide saline solution/DET buffer, 95% EtOH) suitable for long-term preservation at remote tropical sites. Additionally, we tested fecal DNA samples collected from four different scat locations (top, side, bottom, inside). DET buffer was the superior fecal DNA preservation method and collecting fecal DNA from side and top locations of the scat resulted in the highest PCR success rates. For the main genetic study, we assessed the genetic conservation status of all three target species across the country of Belize. We examined levels of genetic diversity within different sites, (2) defined potential genetic clusters/populations, (3) and examined levels of gene flow and population structure for all three target species on a countrywide scale. Furthermore, we compared genetic diversity and gene flow levels among the three target species. Wild felids in Belize showed moderate levels of heterozygosity (HE = 0.60 - 0.70) with jaguars having the lowest genetic diversity with average expected heterozygosities of HE = 0.60 ± 0.05 and allelic richness (AR) of 4.94 ± 0.44 followed by pumas with HE = 0.65 ± 0.06 and AR of 7.52 ± 0.86 and ocelots with HE = 0.70 ± 0.05 and AR of 3.89 ± 0.23. We observed low to moderate levels of differentiation (FST = 0.00 - 0.15) and weak population structure using spatial Bayesian clustering techniques for all three target species. Although levels of genetic diversity and gene flow across the country are still fairly high, we did detect evidence of fragmentation indicating the risk of further habitat loss and fragmentation for wild felids. Felids were simultaneously monitored across all study sites by remote sensing camera traps, which allows for a comparison of density estimates obtained from two different noninvasive survey approaches. Furthermore, analytical methods for density estimation are advancing rapidly, making it difficult to choose the optimal technique. Thus, we compared a variety of density estimators including the conventional approach of estimating abundance ( ) in programs CAPTURE and MARK and dividing abundance by the effective trapping area (ETA), the recently developed spatially explicit capture-recapture (SECR) models, both the likelihood-based approach (ML-SECR) in program DENSITY and the Bayesian approach (B-SECR) in program SPACECAP, and finally the genetic-based mark-recapture one sampling occasion estimator in program CAPWIRE. Although different survey methods using various density estimators produced similar density estimates, confidence levels and coefficients of variation varied, with SECR methods resulting in the least precise estimates. Detection probabilities were generally higher for noninvasive genetic sampling than for camera trapping. Both techniques were shown to be reliable and highly efficient survey methods for density estimation of low-density Neotropical felids living in challenging environments such as the tropics. While less precise, SECR CMR models are probably a more realistic reflection of our uncertainty. They hold great promise for density estimation studies for wide-ranging and territorial carnivore species, especially if precision can be improved through study design or analysis advancements in the future. In conclusion, our results demonstrated that noninvasive sampling techniques such as molecular scatology and remote camera trapping are efficient research approaches to study multiple Neotropical felids in a multifaceted way and on a countrywide scale. We believe that the techniques and analyses developed in this study are widely applicable and relevant to the conservation and management of other elusive and difficult to study wild felids worldwide. / Ph. D.
84

Artificially intelligent foraging

Chalk, Daniel January 2009 (has links)
Bumble bees (bombus spp.) are significant pollinators of many plants, and are particularly attracted to mass-flowering crops such as Oilseed Rape (Brassica Napus), which they cross-pollinate. B. napus is both wind and insect-pollinated, and whilst it has been found that wind is its most significant pollen vector, the influence of bumble bee pollination could be non-trivial when bee densities are large. Therefore, the assessment of pollinator-mediated cross-pollination events could be important when considering containment strategies of genetically modified (GM) crops, such as GM varieties of B. napus, but requires a landscape-scale understanding of pollinator movements, which is currently unknown for bumble bees. I developed an in silico model, entitled HARVEST, which simulates the foraging and consequential inter-patch movements of bumble bees. The model is based on principles from Reinforcement Learning and Individual Based Modelling, and uses a Linear Operator Learning Rule to guide agent learning. The model incoproates one or more agents, or bees, that learn by ‘trial-and-error’, with a gradual preference shown for patch choice actions that provide increased rewards. To validate the model, I verified its ability to replicate certain iconic patterns of bee-mediated gene flow, and assessed its accuracy in predicting the flower visits and inter-patch movement frequencies of real bees in a small-scale system. The model successfully replicated the iconic patterns, but failed to accurately predict outputs from the real system. It did, however, qualitatively replicate the high levels of inter-patch traffic found in the real small-scale system, and its quantitative discrepancies could likely be explained by inaccurate parameterisations. I also found that HARVEST bees are extremely efficient foragers, which agrees with evidence of powerful learning capabilities and risk-aversion in real bumble bees. When applying the model to the landscape-scale, HARVEST predicts that overall levels of bee-mediated gene flow are extremely low. Nonetheless, I identified an effective containment strategy in which a ‘shield’ comprised of sacrificed crops is placed between GM and conventional crop populations. This strategy could be useful for scenarios in which the tolerance for GM seed set is exceptionally low.
85

Évolution de la phénologie des arbres à l'échelle d'un paysage forestier / Evolution of tree phenology at the landscape scale

Soularue, Jean-Paul 13 December 2012 (has links)
La phénologie du débourrement est un caractère adaptatif majeur, sensible aux variations de température. Prédire l'évolution des forêts naturelles tempérées sous l'influence de changements environnementaux nécessite de pouvoir expliquer l'origine des patrons de différentiation clinaux observés pour ce caractère à l'échelle de paysages. Il a été démontré expérimentalement que le débourrement végétatif se produisait en même temps que la floraison. Cela suggère que les croisements se font préférentiellement entre arbres présentant des phénologies du débourrement similaires ; c'est ce que l'on appelle l'homogamie. Alors que la plupart des interprétations de clines de différenciation génétique soulignent l'influence de la sélection divergente, les spécificités de la phénologie du débourrement et ses conséquences sur le système de reproduction sont rarement considérées. A travers une approche par modélisation nous montrons ici dans un premier temps que la seule interaction entre homogamie et flux de pollen peut générer une différentiation génétique clinale à l'échelle d'un paysage sans aucune pression de sélection. Dans un tel contexte théorique, le filtragedes flux de pollen réalisé par l'homogamie en présence d'un gradient environnemental différencie progressivement et durablement les populations. Dans un second temps, nous montrons que l'homogamie amplifie la réponse adaptative des populations à la sélection co-gradient alors qu'il la contraint dans le cas de sélection contre-gradient. Nous montrons par ailleurs que l'homogamie peut induire une différentiation clinale en cas de sélection uniforme. / Timing of bud burst (TBB) is a key adaptive trait affected by temperature variations. Predicting the evolution of natural forests undergoing environmental variations requires to understand the evolutionary dynamics that have resulted in the strong patterns of differentiation characterized for this trait. It has been shown experimentally that the TBB was strongly correlated with the timing off lowering. This suggests that trees having similar TBB tend to mate preferentially, making assortative mating at TBB the default reproduction regime within tree species. Clinal patterns of genetic differentiation have been mostly interpreted as resulting from divergent selection, however, few studies have considered the peculiar features of timing of bud burst. Through a modelling approach based on quantitative genetics models, we first demonstrate here that the sole interaction between assortative mating at TBB and pollen flow can induce a clinal differentiation among populations without any selection pressure. In a such theoretical context, assortative mating filters pollen flow in presence of environmental gradients and progressively shifts the genetic values of populations. Then, we demonstrate that assortative mating amplifies the adaptive response of populations to co-gradient selection, and constrains it in the case of countergradient selection. Finally, we show that assortative mating differentiates populations even in the case of uniform selection.
86

Bases para o manejo da resistência de Bonagota salubricola e Grapholita molesta (Lepidoptera: Tortricidae) a inseticidas em pomares de macieira e pessegueiro / Bases for resistance management of Bonagota salubricola and Grapholita molesta (Lepidoptera: Tortricidae) to insecticides in apple and peach orchards

Silva, Oscar Arnaldo Batista Neto e 22 May 2013 (has links)
A lagarta-enroladeira Bonagota salubricola (Meyrick, 1937) e a mariposa oriental Grapholita molesta (Busck, 1916) (Lepidoptera: Tortricidae) são duas das mais importantes pragas de frutíferas de clima temperado no Brasil. O manejo destes insetos-praga tem sido realizado quase que exclusivamente com inseticidas. Para a implementação de estratégias de manejo pró-ativo de resistência, é importante conhecer o estado atual de suscetibilidade destas espécies a inseticidas para detectar a resistência antes que se observem falhas no controle. Nas condições brasileiras, em regiões onde estes pomares são plantados próximos em algumas regiões, acredita-se que G. molesta disperse para a cultura da maçã após a colheita do pêssego, dependendo da proximidade espacial e temporal dos pomares. Portanto, este trabalho teve como objetivos, caracterizar a suscetibilidade de B. salubricola e G. molesta aos principais inseticidas recomendados para o controle e avaliar a estrutura genética de populações de G. molesta provenientes das culturas da macieira e pessegueiro no Brasil. A caracterização da suscetibilidade foi realizada com bioensaio de ingestão com tratamento superficial da dieta com inseticidas, utilizando-se lagartas neonatas provenientes de populações de B. salubricola coletadas em macieira no Estado do Rio Grande do Sul (safra 2011/12) e de G. molesta provenientes de pomares do Rio Grande do Sul (2010/11 e 2011/12), Santa Catarina (2010/11) e São Paulo (2010/11 e 2011/12). Não foram observadas diferenças na suscetibilidade de populações de campo de B. salubricola em relação à população suscetível de referência aos inseticidas chlorantraniliprole, phosmet, spinetoram, spinosad e tebufenozide, assim como não foram detectadas diferenças na suscetibilidade de populações de G. molesta a chlorantraniliprole, metaflumizone, novaluron, pyriproxyfen e spinetoram. Entretanto, foram verificadas diferenças significativas na sobrevivência de populações de B. salubricola ao novaluron (3,3% de sobrevivência) e de G. molesta aos inseticidas phosmet e tebufenozide, com 2,5 e 4,5% de sobrevivência, respectivamente. Portanto, a frequência de resistência de B. salubricola e G. molesta ainda é baixa aos inseticidas avaliados. Com base nos marcadores mitocondriais e microssatélites foi possível detectar estruturação genética significativa entre as populações de G. molesta que infestam as culturas da macieira e pessegueiro, com indicação de estruturação em função de hospedeiros (?ST = 0,198; P < 0,05) e da distância geográfica (r=0,545; valor de p<0,001). Em geral, a variabilidade genética de G. molesta foi bem distribuída nas regiões produtoras de maçã e pêssego e as barreiras geográficas, as condições edafoclimáticas e o manejo da praga parecem estar limitando o acasalamento entre os indivíduos das populações distintas avaliadas. Portanto, devido ao baixo fluxo gênico entre as populações de G. molesta, as estratégias de manejo da resistência podem ser implementadas no âmbito local para essa praga. / The apple leafroller Bonagota salubricola (Meyrick, 1937) and Oriental fruit moth Grapholita molesta (Busck, 1916) are two of the most important pests of temperate fruit trees in Brazil. Management of these both insect pest has been conducted almost exclusively with insecticides. For the implementation of proactive resistance management strategies, it is important to know the current status of pest susceptibility to insecticides to detect the resistance before control failures with the use of insecticides. In Brazilian conditions, where apple and peach orchards are very often planted close in some regions, it is believed that G. molesta may disperse to apple orchards after harvesting peaches, depending on the spatial and temporal proximity of orchards. Therefore, the objectives of this study were to characterize the susceptibility of B. salubricola and G. molesta to the main insecticides recommended for their control and to evaluate the genetic structure of G. molesta populations from the apple and peach orchards in Brazil. B. salubricola populations were collected in apple orchards in the State of Rio Grande do Sul (2011/12 growing season) and G. molesta populations from orchards in Rio Grande do Sul (2010/11 and 2011/12), Santa Catarina (2010/11) and São Paulo (2010/11 and 2011/12). There were no differences in the susceptibility among field populations of B. salubricola in compared to the susceptible reference population to the insecticides chlorantraniliprole, phosmet, spinetoram, spinosad and tebufenozide and among G. molesta populations to chlorantraniliprole, metaflumizone, pyriproxyfen and spinetoram. However, there were significant differences in survival of B. salubricola populations to novaluron (3.3% survival) and G. molesta populations to insecticides phosmet and tebufenozide, with 2.5 and 4.5% survival, respectively. Therefore, the frequency of resistance of B. salubricola and G. molesta is still low to insecticides evaluated herein. Based on mitochondrial and microsatellites markers, significant genetic structure among G. molesta populations was detected based on the host plant (?ST = 0,198; P < 0,05) and the geographic distance (r=0,545; valor de p<0,001). In general, the genetic variability of G. molesta is well distributed in the producing regions of apple and peach and the geographic barriers, soil and climatic conditions and pest management can be limiting the mating among individuals from distinct populations evaluated in this study. Therefore, due to low gene flow among G. molesta populations in Brazil, resistance management strategies can be implemented at local level.
87

Padrões de distribuição e estrutura genética de schinus molle l. na região do pampa brasileiro

Lemos, Rafael Plá Matielo 08 August 2014 (has links)
Submitted by Ana Damasceno (ana.damasceno@unipampa.edu.br) on 2016-10-10T19:11:40Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Padrões de distribuição e estrutura genética de schinus molle l. na região do pampa brasileiro.pdf: 1391928 bytes, checksum: 2218d5b0fe88623d4d79a44918949a55 (MD5) / Made available in DSpace on 2016-10-10T19:11:41Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Padrões de distribuição e estrutura genética de schinus molle l. na região do pampa brasileiro.pdf: 1391928 bytes, checksum: 2218d5b0fe88623d4d79a44918949a55 (MD5) Previous issue date: 2014-08-08 / Um dos principais aspectos para a ecologia de populações e evolução é o entendimento da conectividade entre os indivíduos e seus grupos. O bioma Pampa apresenta diversos componentes florísticos de grande importância ecológica, e sua estrutura de campo, estépico-savana, vem sendo fragmentada e impactada pelo sistema de produção e pela falta de manejo desse bioma naturalmente frágil. A partir da informação da diversidade genética de populações nativas é possível entender o atual estado de fragmentação ambiental, esclarecer se há fluxo-gênico entre populações, e sugerir formas de manejo que possam garantir a sobrevivência da biodiversidade local. Nesse estudo, Schinus molle L. (Anacardiaceae) foi empregada para avaliar a dinâmica ecológica, a diversidade e a estrutura genética em espécies arbóreas no bioma Pampa. A dinâmica de expansão prevista para a espécie foi determinada através de modelagem de nichos ecológicos e estrutura e diversidade genética foram avaliadas em nove populações amostradas dentro do bioma Pampa stricto sensu, utilizando marcadores microssatélite e AFLP. O mapa da modelagem de nichos ecológicos de S. molle sugere a expansão da espécie sobre o campo, como um fenômeno natural da dinâmica ecológica do bioma. A estrutura genética intra- e inter-populacional sugere limitações ao fluxo gênico e, a diversidade genética intra-populacional é baixa se comparada a espécies com as mesmas características biológicas. O isolamento entre populações e o pequeno tamanho destas parece ser o principal fator interferindo negativamente no ambiente. A manutenção de conexões entre as populações é a ação imediata sugerida para preservar a espécie e o bioma. / One of the main aspects for the population ecology and evolution is the understanding of the connectivity among individuals and their groups. The Pampa biome presents several floristic elements of high ecological importance and its grassy structure, steppic-savanna, has been fragmented and impacted by the production system and by the absence of management of this naturally fragile biome. From the information about genetic diversity of native populations, it is possible to understand the current status of the environment degradation, highlighting the presence of gene flow among populations and to suggest management strategies that could guarantee the survival of the local biodiversity. In this study, Schinus molle L. (Anacardiaceae) was employed to evaluate the ecological dynamic, the genetic diversity and structure in tree species of the Pampa biome. The expected expansion dynamic for this species was determined through ecological niche modeling and the genetic diversity and structure were evaluated in nine populations sampled within the Pampa stricto sensu, using microsatellite and AFLP markers. The ecological niche modeling map of S. molle suggests the species expansion over the grassland as a natural phenomenon of the biomes ecological dynamic. The intra- and inter-population genetic structure suggests limitations to the gene flow and the intra-population genetic structure is low in comparison to species with the same biological traits. The isolation among populations and their small size seems to be the main factor negatively interfering in the environment. The maintenance of connections among the populations is the immediate action suggested to safeguard the species and the biome.
88

Diversidade genética de Qualea grandiflora Mart estimada por microssatélites em quatro áreas de Cerrado do estado de São Paulo / Genetic diversity of Qualea grandiflora Mart estimated by microsatellites in four Cerrado areas of São Paulo

Ritter, Lia Maris Orth 18 July 2012 (has links)
Este estudo trata da estrutura e diversidade genética de uma espécie típica do Cerrado brasileiro, Qualea grandiflora Mart (Vochysiaceae), presente nas diversas fisionomias do bioma. Foram desenvolvidos oito locos microssatélites para analisar 420 amostras de indivíduos adultos pertencentes a quatro populações distribuídas no estado de São Paulo, sendo três delas em unidades administradas pelo Instituto Florestal de São Paulo (Assis, Itirapina e Pedregulho) e uma em propriedade particular (Brotas) além de 300 progênies coletadas de 25 matrizes na área de estudo em Assis. Os resultados mostraram a ocorrência média de 12,9 alelos por loco, sendo que o número médio de alelos efetivos foi seis, além de terem sido encontrados 26 alelos exclusivos nas populações. A média dos valores de Heterozigosidade esperada foi de 0,803 enquanto de Heterozigosidade observada foi de 0,512. O Conteúdo de Informação Polimórfica (PIC) variou de 0,708 a 0,801 nos locos estudados. A média dos valores de fixação foi de 0,349 indicando a presença de endogamia nas populações. Não há presença de clones em nenhuma população. O teste de adesão ao Equilíbrio de Hardy Weinberg confirma o desvio de equilíbrio em todas as populações. Há formação de estrutura populacional nas primeiras classes de distância em todas as populações estudadas, variando de 30 a 40 metros e há uma formação de 3 possíveis grupos de genótipos. A influência do efeito Wahlund foi variável nas populações (de 8,5% até 53,3%). As estimativas de tamanho efetivo populacional foram baixas (menos de 10 indivíduos) e a área mínima viável foi estimada de 4 a 184 hectares, considerando estimativas de curto, médio e longo prazos. Com relação ao sistema reprodutivo, os resultados indicam que Q. grandiflora Mart se reproduz por cruzamentos entre indivíduos parentes e não parentes (0,913). A taxa uniloco foi de 0,632, indicando que há mais cruzamentos entre não aparentados do que aparentados. A taxa de autofecundação foi baixa (0,087) indicando que a espécie é alógama, com pouca pré disposição para autofecundação. Aproximadamente 35% das plantas dentro de progênies eram parentes no grau de irmãos-completos e aproximadamente 57% eram meios-irmãos. Além disso, aproximadamente 8% das progênies eram irmãos de autofecundação. O coeficiente de coancestria estimado nas progênies foi de 0,139 enquanto o índice de fixação foi de aproximadamente 27%. A estimativa do tamanho efetivo indicou que a representatividade genética da descendência é inferior à esperada em progênies de cruzamentos aleatórios: as amostras analisadas correspondem a apenas 13,2 indivíduos de uma população panmítica ideal. Os resultados demonstram que a espécie possui potencial para conservação genética in situ embora a coleta de sementes para manter o tamanho efetivo deva utilizar de um número elevado de árvores. Sugere-se que as áreas estudadas sejam tratadas como Unidades Significativas Evolutivas (USE) e como Unidades Independentes para o Manejo (UIM). / This study deals with the structure and genetic diversity of a species typical of the Brazilian Cerrado, Qualea grandiflora Mart (Vochysiaceae), present in different physiognomies of this biome. We developed eight microsatellite loci to analyze 420 samples of adult individuals from four populations distributed in the state of São Paulo, three of them in units managed by the Forestry Institute of Sao Paulo (Assis, Itirapina and Pedregulho) and one in a private property (Brotas). We also analyzed 300 progeny collected from 25 matrix in Assis. The results showed an average occurrence of 12.9 alleles per locus. The average number of effective alleles was six, and 26 exclusive alleles were found in the populations. The average expected heterozygosity was 0.803 while the observed heterozygosity was 0.512. The polymorphic information content ranged from 0.708 to 0.801 at the loci studied. The mean fixation was 0.349, therefore indicating the presence of inbreeding within populations. There is no presence of clones in the populations. The test of adherence to the Hardy Weinberg Equilibrium confirms the deviation from equilibrium in all populations. There is formation of population structure in the first distance classes in all populations studied, ranging from 30 to 40 meters, and there is a formation of three possible genotype groups. The influence of the Wahlund effect varied among populations (from 8.5% to 53.3%). The effective population size estimates were low (less than 10 individuals) and the minimum viable area was estimated between 4 to 184 hectares, taking into account estimates of short, medium and long terms. Regarding the reproductive system, results indicate that Q. grandiflora Mart reproduces by crosses between relatives and unrelated individuals (0.913). The single locus rate was 0.632, indicating that there are more crosses between unrelated than related individuals. The self-fertilization rate was low (0.087), therefore indicating that the species is allogamous, with little predisposition for self-fertilization. Approximately 35% of the plants within progenies were full-sibs and approximately 57% were half-sibs. In addition, approximately 8% of progenies were self-fertilized brothers. The estimated coefficient of coancestry in progenies was 0.139, while the rate of fixation was about 27%. The estimated effective size indicated that the genetic representativeness of the offspring is lower than the expected in random cross progenies: the samples analyzed account for only 13.2 individuals in a ideal panmitic population. The results show that this species has potential for in situ genetic conservation, although the collection of seeds to maintain the effective size should use a large number of trees. It is suggested that the studied areas be treated as evolutionary significant units and as independent units for management.
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Postglacial Population History of the Common Shrew (<i>Sorex araneus</i>) in Fennoscandia : Molekylära studier av återkolonisation, könsbundet genflöde och kromosomrasbildning. / Den vanliga näbbmusens (<i>Sorex araneus</i>) postglaciala populationshistoria i Fennoskandien : Molekylära studier av återkolonisation, könsbundet genflöde och kromosomrasbildning.

Andersson, Anna-Carin January 2004 (has links)
<p>The common shrew, <i>Sorex araneus</i>, has one of the most variable karyotypes among mammals, displaying numerous chromosomes races throughout its distribution, which can be categorized into different karyotypic groups. The objective of this thesis was to examine the postglacial population history of Fennoscandian common shrews using autosomal microsatellites, mitochondrial DNA (mtDNA) and a Y chromosome specific microsatellite (L8Y).</p><p>Autosomal microsatellites and mtDNA revealed weak genetic structure over a hybrid zone between the karyotypically divergent Northern and Western karyotypic groups. However, the genetic structure displayed by the Y chromosome microsatellite was orders of magnitude higher. Hence, considerable chromosomal differences between the groups do not prevent female gene flow, while male gene flow is reduced (cf. Haldane's rule). Further, the results suggest that the Haldane effect may be caused by the chromosomal differences between the karyotypic groups.</p><p>No mtDNA differentiation was observed either between chromosome races or between the Northern and Western karyotypic groups in Fennoscandia. The combined pattern of karyotypic and mtDNA variation of Fennoscandian common shrews, suggest bi-directional postglacial recolonisation from a single refugium in Europe. The variation of the Y-linked microsatellite supported this conclusion. In contrast, significant mtDNA structure, discordant with the karyotypic variation, revealed that common shrews in southern Finland belong to a different lineage than remaining Fennoscandian regions, implying postglacial recolonisation from a different source.</p><p>MtDNA variation of the chromosome races in Sweden supports the hypothesis that three races of the Western karyotypic group have been formed through whole arm reciprocal translocations (WARTs), as suggested by their mutual karyotypic variation. The variation of the molecular markers supports the theory of rapid karyotypic evolution in the common shrew.</p>
90

Postglacial Population History of the Common Shrew (Sorex araneus) in Fennoscandia : Molekylära studier av återkolonisation, könsbundet genflöde och kromosomrasbildning. / Den vanliga näbbmusens (Sorex araneus) postglaciala populationshistoria i Fennoskandien : Molekylära studier av återkolonisation, könsbundet genflöde och kromosomrasbildning.

Andersson, Anna-Carin January 2004 (has links)
The common shrew, Sorex araneus, has one of the most variable karyotypes among mammals, displaying numerous chromosomes races throughout its distribution, which can be categorized into different karyotypic groups. The objective of this thesis was to examine the postglacial population history of Fennoscandian common shrews using autosomal microsatellites, mitochondrial DNA (mtDNA) and a Y chromosome specific microsatellite (L8Y). Autosomal microsatellites and mtDNA revealed weak genetic structure over a hybrid zone between the karyotypically divergent Northern and Western karyotypic groups. However, the genetic structure displayed by the Y chromosome microsatellite was orders of magnitude higher. Hence, considerable chromosomal differences between the groups do not prevent female gene flow, while male gene flow is reduced (cf. Haldane's rule). Further, the results suggest that the Haldane effect may be caused by the chromosomal differences between the karyotypic groups. No mtDNA differentiation was observed either between chromosome races or between the Northern and Western karyotypic groups in Fennoscandia. The combined pattern of karyotypic and mtDNA variation of Fennoscandian common shrews, suggest bi-directional postglacial recolonisation from a single refugium in Europe. The variation of the Y-linked microsatellite supported this conclusion. In contrast, significant mtDNA structure, discordant with the karyotypic variation, revealed that common shrews in southern Finland belong to a different lineage than remaining Fennoscandian regions, implying postglacial recolonisation from a different source. MtDNA variation of the chromosome races in Sweden supports the hypothesis that three races of the Western karyotypic group have been formed through whole arm reciprocal translocations (WARTs), as suggested by their mutual karyotypic variation. The variation of the molecular markers supports the theory of rapid karyotypic evolution in the common shrew.

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