Dissertations / Theses: 'Founder population'

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黃冠萍 and Kwun-ping Flora Wong. "A study of MSH2 founder mutation in Hong Kong population." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2008. http://hub.hku.hk/bib/B41712316.

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Wong, Kwun-ping Flora. "A study of MSH2 founder mutation in Hong Kong population." Click to view the E-thesis via HKUTO, 2008. http://sunzi.lib.hku.hk/hkuto/record/B41712316.

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Väisänen, M. L. (Marja-Leena). "Fragile X syndrome in Northern Finland:molecular, diagnostic and population genetic aspects." Doctoral thesis, University of Oulu, 1999. http://urn.fi/urn:isbn:9514253779.

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Abstract Fragile X syndrome, the most common inherited form of mental retardation syndrome, is caused by an expansion of the CGG trinucleotide repeat in the 5' UTR of the FMR1 gene, with concurrent hypermethylation of the region, which represses FMR1 expression. The syndrome is associated with the folate-sensitive chromosomal fragile site at Xq27.3 (FRAXA), where the gene responsible for the syndrome was first localized by linkage analysis using RFLP markers. In this study the linkage relationships of the RFLP markersat Xq27-28 and the characteristics of the CGG repeat expansion were investigated in northern Finnish fragile X families and molecular diagnostic methods were applied in order to improve diagnosis of the syndrome. Furthermore, the origin of fragile X mutations in the northern part of Finland was studied by haplotype analysis. Linkage studies were performed in 34 northern Finnish fragile X families/pedigrees using a total of 15 RFLPs (defining 11 loci). A refined genetic map around FRAXA including five RFLP markers having recombination fractions of 0.04 or less with FRAXA was obtained in an international study of 112 affected families, containing linkage data on twelve northern Finnish families. Linkage analysis significantly improved carrier detection in fragile X families compared with previous cytogenetic methods used in diagnosis. The most efficient RFLP-based protocol for carrier detection was proposed, which is based on use of the most adjacent markers and a minimum number of restriction enzymes. CGG repeat expansion of the FMR1 gene was investigated in original families collected for linkage studies and additional new ones. Large CGG repeat expansions (Δ > 500 bp) with concomitant methylation of the adjacent CpG island, i.e. full mutations, were found to be associated with mental retardation completely in males, but only 50% of the females having a full mutation were mentally impaired. Premutations (Δ < 700 bp) were found in healthy carriers. There was a size range of Δ = 500 to 700 bp, where the expansions could be either abnormally methylated or non-methylated, and it appeared that methylation is more important in determining the phenotype than the exact size of an expansion. Instability of the enlarged CGG repeats was detected, leading preferentially to size increases in successive generations. The instability of premutations was found to be stronger and the size increases larger in maternal than in paternal transmissions, and transition to a full mutation occurred only in female transmissions. In addition, the size of a maternal premutation was shown to have an important influence on the risk of its transition to a full mutation when transmitted. The critical premutation size leading invariably to full mutation in the offspring was found to be between Δ = 175 to 200 bp. In one of the studied families a rare contraction of a paternal premutation to a normal CGG repeat number in one of the daughters and further in her son was detected. Direct mutation analysis including measurement of the CGG repeat size and hypermethylation allowed unambiguous diagnosis of carriers and affected individuals in most cases. Haplotype analysis using two tightly linked microsatellite markers flanking the CGG repeat mutation was performed in 60 unrelated northern and eastern Finnish fragile X families. A significant difference was found in allelic and haplotypic distributions between normal X and fragile X chromosomes. A single haplotype, which was present only in 8% of the normal X chromosomes, accounted for 80% of the fragile X chromosomes. This enrichment of one fra(X) mutation in the Finnish population suggests founder effect.

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Roos, J. L. (Johannes Louw). "Genetic variation and clinical variables contributing to Schizophrenia in a Founder Population from South Africa." Thesis, University of Pretoria, 2014. http://hdl.handle.net/2263/44335.

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Thirty publications are submitted. They deal with findings of the genetic architecture of schizophrenia in an Afrikaner founder population and clinical related variables pertaining to this population. The initial research findings supported the appropriateness of the Afrikaner population for mapping complex traits using both linkage and linkage disequilibrium (LD) approaches. Basic sample descriptors and cardinal symptoms of schizophrenia in the US and South African populations were equivalent. It was concluded that the results from our genetic study of schizophrenia in the Afrikaner sample will be applicable to other populations. It was found that early non-psychotic childhood deviance (in the first ten years of life) distinguished a distinct subtype of schizophrenia patient, and that the form of early deviance manifested, was meaningful linked to later disease outcome; and that it may be a possible endophenotypic marker in schizophrenia but not in bipolar disorder. Schizophrenia genetic research used linkage analysis, association studies and exome sequencing studies as it became available in the last few years. We addressed the role of the individual genes from the 22q11 locus (prototype CNV described in schizophrenia). Systematic screening of the 26 genes residing in this locus identified PRODH2, ZDHHC8, NOGO Receptor 1 (RTN4R) gene as contributing to schizophrenia risk associated with this region. Linkage genome-wide scans, using both less dense (10cM) and more dense scans (2cM), identified a locus on chromosome 1 and 13. Recent fine mapping on chromosome 13q32-34 and brain expression analysis implicates MYO16 in schizophrenia (not included in the 30 publications). For the first time a probound with a uniparental disomy (UPD) of the entire chromosome 1, was identified, which further support the involvement of chromosome 1 in schizophrenia. We confirmed the previous reported rate of 2% frequency of 22q11 deletions in adult schizophrenia Afrikaner patients and provided a two-stage screening protocol to identify these patients in clinical practice. As more patients were recruited for this study certain comorbid conditions became obvious including marijuana use/abuse and obsessive compulsive disorder (OCD) and obsessive compulsive symptoms (OCS). Approximately half of the male patients and a quarter of the female patients used or abused marijuana. Male users of marijuana with prominent early non-psychotic deviant behaviour in the first 10 years of life had the lowest mean age of criteria onset (18.4 years) with a poor prognosis. The prevalence of OCD/OCS in this population was 13.2% and differs from other ethnic groups in South Africa, and was associated with significant psychopathology and poor prognosis. As the research progressed the emphasis has changed from familial cases with the disease to sporadic cases (non-familial). We offered the first clear view of the genetic landscape of schizophrenia. We found that rare de novo structural mutations at many different loci are significantly enriched and contribute to schizophrenia vulnerability in sporadic cases with the disease. We also demonstrated that genes contribute to familial schizophrenia, while new mutations are less prominent. The study of schizophrenia in the Afrikaner founder population has helped to clear the view of the genetic landscape of schizophrenia. Thesis (DSc)--University of Pretoria, 2014. tm2015 Psychiatry DSc Unrestricted

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Kayim, Mehmet. "Founder Effect In Reintroduced Anatolian Mouflon Ovis Gmelinii Anatolica Valenciennes 1856 Populations." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12610015/index.pdf.

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Reintroduction of Anatolian mouflon population at Bozdag Protection &amp Breeding Station to its former habitats(Emremsultan Wildlife Development Area in Ankara-Nallihan, and Karadag in Karaman) started in 2004. The magnitude of genetic change among Bozdag and reintroduced populations was evaluated by 11 microsatellite loci. Study populations revealed close results (&plusmn st.dev.) &ndash Bozdag population: nk = 2.9091 (&plusmn 1.1362), AE = 2.0250 (&plusmn 0.9537), Ho = 0.3830 (&plusmn 0.2717), He = 0.3956 (&plusmn 0.2746) Nallihan population: nk = 2.9091 (&plusmn 1.1362), AE = 2.0592 (&plusmn 0.9451), Ho = 0.4086 (&plusmn 0.2977), He = 0.4052 (&plusmn 0.2767) and Karadag population: nk = 2.5455 (&plusmn 1.1282), AE = 1.8809 (&plusmn 0.8758), Ho = 0.3388 (&plusmn 0.2775), He = 0.3607 (&plusmn 0.2716). Population differences for major genetic parameters were not significant (p &gt 0.05) by comparisons with paired t-test. Also, temporal change in genetic diversity for Bozdag population was investigated by comparison with temporal data. Temporal changes in genetic parameters were found to be not significant and possible causes for differences were argued. Additionally, genetic diversity and PI computations for different traps were verified and compared to uncover any potential bias due to the catching method. Comparisons did not reveal significant differences illustrating the homogeneity among traps. On the other hand, simulations detected the higher sensitivity of allelic diversity (A) to founder events than P and heterozygosity (Ho &amp He) levels which supports heterozygosity excess method for bottleneck analysis. With the same simulation analysis, observed genetic diversity within reintroduced samples were found to be in the ranges of expectation (99% CI) indicating that translocated individuals were chosen randomly. Bottleneck analysis based on heterozygosity excess method (one-tailed test for heterozygosity excess: pSMM = 0.28515, pTPM = 0.06445, pIAM = 0.02441) and allele frequency distributions method (normal L-shaped) could not detect a recent genetic bottleneck for Bozdag population. However, simulations determined that these two methods are prone to type II error. Bottleneck detection failure for the study population is probably due to type II error instead of other sources of error like violations of model assumptions.

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Paré, Guillaume. "Genetic analysis of 100 loci for coronary artery disease and associated phenotypes in a founder population." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=99196.

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Coronary artery disease (CAD) is a major health concern for both developed and developing countries. With a heritability estimated at around 50%, there is a strong rationale to better define the genetic contribution of CAD. In order to do so, my thesis project consists in the genetic analysis of over 1400 individuals from the Saguenay Lac St-Jean region using 1536 single nucleotide polymorphisms in 103 candidate genes for CAD. Using this data, suggestive linkage for HDL cholesterol was found on chromosome 1 and several significant associations were observed with lipoprotein-related traits as well as adiponectin plasma concentration, including two novel associations.

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Wajiki, Yuichi. "Studies on Genetic Diversity and Its Maintenance in the Japanese Population of Japanese Crested Ibis (Nipponia nippon)." Kyoto University, 2016. http://hdl.handle.net/2433/215226.

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Cameron, Emilie C. "Fruit Fly Pests of Northwestern Australia." University of Sydney, 2007. http://hdl.handle.net/2123/1711.

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Doctor of Philosophy(PhD), Until recently, Northwestern Australia was thought to be relatively free of serious fruit fly pests. Although a noxious strain, present in Darwin since 1985, was widely believed to be an infestation of the Queensland fruit fly, Bactrocera tryoni, from the East coast, the fruit flies present outside this area were believed to be the benign endemic species, B. aquilonis. However, during the year 2000, infestations of fruit flies were discovered on major commercial crops in both Western Australia and the Northern Territory. It was not known whether these outbreaks were due to an invasion of the major pest species, Bactrocera tryoni, a change in the behaviour of B. aquilonis, or a hybridisation event between the two species. Finding the source of these outbreaks has been complicated by the fact that, since B. tryoni and B. aquilonis are virtually indistinguishable morphologically, it was not known which species are present in the region. Traditionally any tryoni complex fly caught in the Northwest was called B. aquilonis based solely on location. In order to get a good population profile of the region, an extensive trapping program was set up to include flies from urban areas, commercial crops and natural areas where the benign strain is thought to remain. Tests of genetic differentiation and clustering analyses revealed a high degree of homogeneity in the Northwest samples, suggesting that just one species is present in the region. The Northwest samples were genetically differentiated from the Queensland samples but only to a small degree (FST =0.0153). MtDNA sequencing results also showed a small degree of differentiation between these regions. A morphological study of wing shape indicated that there are some minor identifiable morphological differences between East coast and Northwest laboratory reared flies. This difference was greater than that seen between B. jarvisi populations across the same geographic range. The results suggest that the flies caught in the Northwest are a separate population of B. tryoni. Soon after pest flies were discovered in Darwin, a population became established in Alice Springs. This population had a low genetic diversity compared with Queensland and Darwin populations, and showed evidence of being heavily founded. In 2000, an outbreak was discovered in the nearby town of Ti Tree. Due to the geographic and genetic similarity of these populations, Alice Springs was determined to be the source of the Ti Tree outbreak. To investigate the founding of these populations, a program was developed to estimate the propagule size. Using a simulation method seven different statistics were tested for estimating the propagule size of an outbreak population. For outbreaks originating from populations with high genetic diversity, the number of alleles was a good estimator of propagule size. When, however, the genetic diversity of the source population was already reduced, allele frequency measures, particularly the likelihood of obtaining the outbreak population from the source population, gave more accurate estimates. Applying this information to the Alice Springs samples, it was estimated that just five flies were needed to found the major population in and around Alice Springs. For Ti Tree, the propagule size was estimated to be 27 flies (minimum 10). In 2000, a much larger outbreak occurred in the developing horticultural region of Kununurra in northern Western Australia. An important question for the management of the problem is whether there is an established fly population or the flies are reinvading each year. This population was found to have a large amount of gene flow from the Northern Territory. Within the Kununurra samples, one group of flies was genetically differentiated from all the other samples. This group came from a small geographic area on the periphery of Kununurra and appeared to be the result of an invasion into this area at the time when the population was building up following the dry season. A further threat to the Northwest horticultural regions comes from B. jarvisi. A recent increase in the host range of this species has lead to speculation that it may become a greater pest in Northwestern Australia. At the present time, protocols for the population monitoring and disinfestation of this species are not in place. Here it is shown that B. jarvisi eggs are more heat tolerant than B. tryoni eggs and that monitoring of B. jarvisi populations is possible using cue lure traps placed according to fruiting time and location of their favoured host, Planchonia careya.

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9

Cameron, Emilie C. "Fruit Fly Pests of Northwestern Australia." Thesis, The University of Sydney, 2006. http://hdl.handle.net/2123/1711.

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Until recently, Northwestern Australia was thought to be relatively free of serious fruit fly pests. Although a noxious strain, present in Darwin since 1985, was widely believed to be an infestation of the Queensland fruit fly, Bactrocera tryoni, from the East coast, the fruit flies present outside this area were believed to be the benign endemic species, B. aquilonis. However, during the year 2000, infestations of fruit flies were discovered on major commercial crops in both Western Australia and the Northern Territory. It was not known whether these outbreaks were due to an invasion of the major pest species, Bactrocera tryoni, a change in the behaviour of B. aquilonis, or a hybridisation event between the two species. Finding the source of these outbreaks has been complicated by the fact that, since B. tryoni and B. aquilonis are virtually indistinguishable morphologically, it was not known which species are present in the region. Traditionally any tryoni complex fly caught in the Northwest was called B. aquilonis based solely on location. In order to get a good population profile of the region, an extensive trapping program was set up to include flies from urban areas, commercial crops and natural areas where the benign strain is thought to remain. Tests of genetic differentiation and clustering analyses revealed a high degree of homogeneity in the Northwest samples, suggesting that just one species is present in the region. The Northwest samples were genetically differentiated from the Queensland samples but only to a small degree (FST =0.0153). MtDNA sequencing results also showed a small degree of differentiation between these regions. A morphological study of wing shape indicated that there are some minor identifiable morphological differences between East coast and Northwest laboratory reared flies. This difference was greater than that seen between B. jarvisi populations across the same geographic range. The results suggest that the flies caught in the Northwest are a separate population of B. tryoni. Soon after pest flies were discovered in Darwin, a population became established in Alice Springs. This population had a low genetic diversity compared with Queensland and Darwin populations, and showed evidence of being heavily founded. In 2000, an outbreak was discovered in the nearby town of Ti Tree. Due to the geographic and genetic similarity of these populations, Alice Springs was determined to be the source of the Ti Tree outbreak. To investigate the founding of these populations, a program was developed to estimate the propagule size. Using a simulation method seven different statistics were tested for estimating the propagule size of an outbreak population. For outbreaks originating from populations with high genetic diversity, the number of alleles was a good estimator of propagule size. When, however, the genetic diversity of the source population was already reduced, allele frequency measures, particularly the likelihood of obtaining the outbreak population from the source population, gave more accurate estimates. Applying this information to the Alice Springs samples, it was estimated that just five flies were needed to found the major population in and around Alice Springs. For Ti Tree, the propagule size was estimated to be 27 flies (minimum 10). In 2000, a much larger outbreak occurred in the developing horticultural region of Kununurra in northern Western Australia. An important question for the management of the problem is whether there is an established fly population or the flies are reinvading each year. This population was found to have a large amount of gene flow from the Northern Territory. Within the Kununurra samples, one group of flies was genetically differentiated from all the other samples. This group came from a small geographic area on the periphery of Kununurra and appeared to be the result of an invasion into this area at the time when the population was building up following the dry season. A further threat to the Northwest horticultural regions comes from B. jarvisi. A recent increase in the host range of this species has lead to speculation that it may become a greater pest in Northwestern Australia. At the present time, protocols for the population monitoring and disinfestation of this species are not in place. Here it is shown that B. jarvisi eggs are more heat tolerant than B. tryoni eggs and that monitoring of B. jarvisi populations is possible using cue lure traps placed according to fruiting time and location of their favoured host, Planchonia careya.

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Broders, Hugh G. "Population genetic structure and the effect of founder events on the genetic variability of moose (Alces alces) in Canada." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0035/MQ47418.pdf.

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11

Alphonse, Peter AS. "Genetic variants affecting responses of plasma lipids and cholesterol kinetics to dietary cholesterol versus plant sterol consumption in a founder population." Lipids-Springer, 2015. http://hdl.handle.net/1993/31823.

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Lowering plasma LDL-cholesterol (LDL-C) and increasing HDL-cholesterol (HDL-C) concentrations remain the primary targets in cardiovascular disease (CVD) risk reduction. Dietary cholesterol and plant sterols differentially modulate cholesterol kinetics and lipoprotein distribution. Inter-individual variations in the rates of cholesterol absorption and synthesis, and the reciprocal interaction between them affect the responses to dietary sterols. Genetic heterogeneity profoundly influences such responsiveness. However, limited research exists on the genetic determinants of dietary cholesterol versus plant sterols responsiveness in healthy individuals, especially in a founder population, such as the Hutterites in Manitoba of European descent who practice a communal living system. Our study examined the differential effects of dietary cholesterol versus plant sterol consumption on plasma lipoprotein levels, subclasses, and cholesterol kinetics and assessed how genetic variants influenced these responses. A double-blind, randomized, crossover study with three interventional periods of 4 wk duration each was conducted. Healthy Hutterite individuals (n=49) from Manitoba consumed daily either 2 g of plant sterols or 600 mg of cholesterol incorporated into milkshakes, or a placebo during each period. Plasma lipid profile and lipoprotein subclass distribution were determined. Cholesterol absorption and synthesis were assessed by stable isotopic tracer techniques. Participants were genotyped for 38 candidate single nucleotide polymorphisms across 25 genes involved in cholesterol and lipoprotein metabolism. Dietary cholesterol consumption increased plasma TC, HDL-C concentrations and large HDL subclasses with no changes in cholesterol absorption or synthesis. In contrast, plant sterol intake failed to reduce LDL-C concentrations, with a modest reduction in cholesterol absorption, and did not affect lipoprotein subclasses. However, a large non-compensatory increase in cholesterol synthesis was observed due to plant sterol consumption. Gender and common genetic variants affected plasma HDL-C and HDL subclass distribution to dietary cholesterol and plant sterol consumption. ACAT2 and NPC1L1 gene variants affected plasma campesterol and β-sitosterol concentrations respectively, to plant sterol intake by modifying cholesterol absorption. In summary, our results demonstrate that dietary cholesterol and plant sterol intake differentially modulate cholesterol trafficking in a manner dependent on common genetic variants and gender in healthy individuals. Such knowledge facilitates the development of effective cholesterol lowering strategies for the alleviation of CVD burden. October 2016

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12

Wang, Sophie. "Optimizing rare variant association studies in theory and practice." Thesis, Harvard University, 2014. http://dissertations.umi.com/gsas.harvard:11430.

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Genome-wide association studies (GWAS) have greatly improved our understanding of the genetic basis of complex traits. However, there are two major limitations with GWAS. First, most common variants identified by GWAS individually or in combination explain only a small proportion of heritability. This raises the possibility that additional forms of genetic variation, such as rare variants, could contribute to the missing heritability. The second limitation is that GWAS typically cannot identify which genes are being affected by the associated variants. Examination of rare variants, especially those in coding regions of the genome, can help address these issues. Moreover, several studies have recently identified low-frequency variants at both known and novel loci associated with complex traits, suggesting that functionally significant rare variants exist in the human population.

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Herzig, Anthony Francis. "Studying the genetic architecture of complex traits in a population isolate." Thesis, Sorbonne Paris Cité, 2019. http://www.theses.fr/2019USPCC110.

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Mon projet de thèse vise à exploiter le potentiel des isolats de population pour étudier la composante génétique des maladies multifactorielles. En effet, les isolats peuvent faciliter l'identification des facteurs génétiques habituellement trop rares en population générale. Cette thèse est composée de deux études principalement : l'imputation génétique et l'analyse de l'héritabilité. Chacune de ces études ont été abordée sous deux angles : l’un théorique, s’appuyant sur une vaste étude de simulations basée sur les caractéristiques de la population isolée du Cilento, permettant d’évaluer des stratégies d’analyse et de déterminer la plus adéquate ; l’autre appliqué, s’appuyant sur l’analyse de données génétiques réelles issues de la même population.L'imputation génétique est une étape cruciale pour effectuer des analyses d'association dans un isolat et représente une méthode peu couteuse pour obtenir les séquences complètes du génome ou de l’exome des individus de la population. L'efficacité de cette approche dépend de la précision de l’imputation ; nous avons donc étudié plusieurs stratégies pour obtenir une précision d'imputation maximale dans un isolat. Nous avons montré que les logiciels utilisant des algorithmes qui s’appuient sur les caractéristiques particulières des isolats n’étaient pas, de façon inattendue, aussi performants que ceux conçus pour les populations générales. De plus, malgré la disponibilité de panels de référence publics contenant plusieurs milliers de chromosomes, nous avons confirmé qu’un panel de référence spécifique de la population d’étude, même de taille très réduite, était essentiel pour la qualité de l’imputation. Ceci était d’autant plus vrai pour les variantes rares.Pour de nombreux traits, il existe des discordances entre les estimations de l'héritabilité obtenues à partir d’individus apparentés et à partir d’individus non apparentés. En particulier, la plupart des chercheurs considère que les effets dominants (non additifs) ne jouent pas un rôle majeur malgré les résultats contrastés des études sur les isolats. Notre deuxième analyse a révélé des mécanismes possibles pour expliquer la disparité de ces estimations publiées entre populations isolées et populations générales. Cela nous a permis de faire des déductions intéressantes pour nos propres analyses dans le Cilento. En particulier, nous avons identifié la possibilité d'une composante de dominance non nulle pour les niveaux de lipoprotéines de basse densité (LDL). Cela nous a amenés à effectuer des analyses d'association pan-génomique des composantes additives et non-additives pour LDL dans le Cilento et nous avons pu identifier des gènes qui avaient déjà été liés au trait dans d'autres études.Dans le contexte de nos deux études, nous avons observé l'importance de conserver l'incertitude génotypique (dosage pour l’imputation, vraisemblance des génotypes pour les données de séquençage). Dans la perspective de cette thèse, nous avons proposé des moyens d’incorporer cette incertitude à certaines méthodes utilisées dans ce projet.Nos résultats concernant les stratégies d'imputation et l'analyse de l'héritabilité seront très utiles pour la poursuite de l'étude de l'isolat de Cilento. Mais, ils seront également instructifs pour les chercheurs travaillant sur d'autres populations isolées et également applicables plus généralement à l'étude des maladies complexes My thesis project is concerned with tapping the potential of population isolates for the dissection of complex trait architecture. Specifically, isolates can aid the identification of variants that are usually rare in other populations. This thesis principally contains in depth investigations into genetic imputation and heritability analysis in isolates. We approached both of these studies from two main angles; first from a methodological standpoint where we created extensive simulation datasets in order to investigate how the specificities of an isolate should determine strategies for analyses. Secondly, we demonstrated such concepts through analysis of genetic data in the known isolate of Cilento. Imputation is a crucial step to performing association analyses in an isolate and represents a cost-efficient method for gaining dense genetic data for the population. The effectiveness of imputation is of course dependent on its accuracy. Hence, we investigated the wide range of possible strategies to gain maximal imputation accuracy in an isolate. We showed that software using algorithms which specifically evoke known characteristics of isolates were, unexpectedly, not as successful as those designed for general populations. We also demonstrated a very small study specific imputation reference panel performing very strongly in an isolate; particularly for rare variants. For many complex traits, there exist discordances between estimates of heritabilities from studies in closely related individuals and from studies on unrelated individuals. In particular, we noted that most researchers consider dominant (non-additive) genetic effects as unlikely to play a significant role despite contrasting results from previous studies on isolates. Our second analysis revealed possible mechanisms to explain such disparate published heritability estimates between isolated populations and general populations. This allowed us to make interesting deductions from our own heritability analyses of the Cilento dataset, including an indication of a non-null dominance component involved in the distribution of low-density lipoprotein level measurements (LDL). This led us to perform genome-wide association analyses of additive and non-additive components for LDL in Cilento and we were able to identify genes that had been previously linked to the trait in other studies. In the contexts of both of our studies, we observed the importance of retaining genotype uncertainty (genotype dosage following imputation or genotype likelihoods from sequencing data). As a prospective of this thesis, we have proposed ways to incorporate this uncertainty into certain methods used in this project. Our findings for imputation strategies and heritability analysis will be highly valuable for the continued study of the isolate of Cilento but will also be instructive to researchers working on other isolated populations and also applicable to the study of complex diseases in general

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MORANI, GABRIELE. "Identification of plasma proteins causally related to Multiple Sclerosis via a Mendelian Randomization approach: a study on multiplex families from the founder population of the Nuoro province (Sardinia)." Doctoral thesis, Università degli studi di Pavia, 2019. http://hdl.handle.net/11571/1246630.

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Background: The pathogenesis of Multiple Sclerosis (MS) is poorly understood. A better understanding of the causal pathways involved in this disease is needed as a basis for developing new therapies. Objectives: With this study we try to assess the existence of causal relationships between a large set of candidate plasma proteins and MS. Our analysis is based on 20 multiplex families from the founder and genetically homogeneous population of the Nuoro province, Sardinia (Italy). Our aim is to improve our understanding of the pathophysiological bases of this disease, providing important candidates to be prioritized for further studies on MS and for drug discovery possibly leading to the improvement of the clinical conditions of the subjects affected by this disabling disease. Methods: We investigated each protein, in turn, for a possible causal effect on MS, taking advantage of the use of Mendelian Randomization (MR) methods to avoid the classical biases that affects observational studies. To overcome the limitations of observational studies we adopted a MR approach to the analysis, where genetic variants act as instrumental variables for the assessment of the putative causal effect. We applied different MR methods based on summary statistics: Inverse-Variance Weighted as the main method and the Weighted Median Estimator and Egger regression for sensitivity analysis purpose. The data supported causality of a number of proteins, which we then checked via bidirectional MR analysis to assess potential reverse causation. Results: In the end, 3 proteins showed significant results with both Bonferroni and Benjamini-Hochberg corrections, in particular MOBP, ZMYND19 and EFCAB14. Following the bidirectional analysis though, ZMYND19 showed a significant result in the reverse-direction too, suggesting some reverse causation effect. It seems that, in this case, the disease itself could influence the level of this protein in plasma. The final and most interesting findings in the end are therefore MOBP and EFCAB14. Conclusion: Whereas MR methods are typically applied to high-level exposures, such as obesity and cholesterol, ours is one of the few studies that uses standard MR methods to identify genes that drive the disease by influencing the concentration of their coded proteins, applying a systematic routine of analysis on a very large set of candidate proteins in what seems to be a very promising and useful exploratory approach. We confirmed two proteins being causally related to MS. The variants in the genes coding for these proteins were found statistically associated to MS in previous studies.

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Andersson, Bea Angelica. "Analysis of Selection and Genetic Drift in a Dioecious Plant : Spatial Genetic Structure and Selection in Phenotypic Traits in a Young Island Population of Silene dioica." Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-96275.

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Selection and genetic drift are often competing forces in shaping genetic structure in populations. Genetic drift will often effectively cancel out the effect of selection when population sizes are small, such as in colonizing island populations. On a small island in the Skeppsvik Archipelago in northern Sweden, a newly founded population of Silene dioica has been monitored since it first established around 1993. Though inhabiting an area of merely 173 m2, the population has been shown to exhibit a genetically differentiated patch structure where closely related individuals are tightly grouped, distanced from other family groups. In this study, the effect of selection was evaluated as compared to that of genetic drift. Variation in phenotypic traits in flowers, leaves and stalks were compared to that of neutral markers, in the form of PST and FST measures, to assess a measure of what proportion of differentiation among patches in phenotypic traits could not be attributed to genetic drift. Males and females were analysed separately to obtain measures of sex specific selection. Signs of divergent and stabilizing selection were found in several traits in both males and females despite the small spatial scale and short time since colonization. Further analysis is needed to assess explanations for trait divergence among patches and direction of selection.

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Osmers, Karl Benjamin. "Genetic structuring between gemsbok (oryx gazella) populations and the impact of the founder effect on isolated populations." Thesis, University of Limpopo (Turfloop Campus), 2012. http://hdl.handle.net/10386/746.

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Thesis (M.Sc. (Zoology)) --University of Limpopo, 2012 A microsatellite-based study was performed on five populations of Gemsbok (Oryx gazella). This study was aimed at estimating genetic diversity in introduced South African gemsbok populations (an opportunity that arose when additional animals from the same source were imported into South Africa), and determine genetic structure. Population sizes at the time of sampling were: Namibia (n = 6500), Cohen (n = 70), Tempelhof (n = 55), STS Kalahari Game Ranch (n = 1000) and Elias (n = 35). The purpose of the study was to determine the genetic structure of the aforementioned O. Gazelle populations, and to assess the impact of the founder effect on isolated populations. The following primers (BMS1237, MAF46, OARFC304, OARHH64, ETH225, RBP3, MAF50, HDZ8) developed for commercial purposes in the bovine group were used. Genetic diversity were calculated as Expected Heterozygosity (He), proportion of polymorphic loc (P) and number of alleles per locus (A). Conformation to expected Hardy-Weinberg equilibrium of genotypes was also determined, using a Chi-square test. Tests for the signature of bottlenecks in the populations studied were also performed. Genetic drift/differentiation was tested by using FST and RST coefficients. Assignment tests were performed to identify the true number of genetic populations (clusters). Genetic distance was used as an additional measure of differentiation. The results indicated that all loci showed allelic polymorphism in all the populations except one (at the OARHH64 locus). The South African Cohen population displayed the highest level of genetic diversity, with He = 0.595 ± 0.247. This population also did not show evidence of a bottleneck. Genetic distance values indicated the greatest similarity between the Cohen and Namibian populations, in line with the Namibian origin of the Cohen group. Greatest distance was observed between the STS and Tempelhof populations. conclusion, results from this study reflects the origins of populations and suggest that inbreeding in small isolated populations may be less than previously estimated.

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Kohn, Deborah Diane. "Effects of genetic variability and founder number in small populations of an annual plant." Thesis, Imperial College London, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.286448.

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Eriksson, Viktor. "Lämpliga stampopulationer av mellanspett (Dendrocopos medius) för återintroduktion i Linköping, Östergötland." Thesis, Linköpings universitet, Institutionen för fysik, kemi och biologi, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-158034.

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The middle spotted woodpecker (Dendrocopos medius) became extinct in Sweden in 1982. The last population inhabited a fragmented area of 300 km2 and were for a long time a characteristic species for the oak stands of Sturefors and BjärkaSäby, south of Linköping. The reason why the species got extinct depends mostly on habitat fragmentation. Also, the extinction got hasten by harsh wintering conditions. The purpose of this study is to evaluate which of current populations of Dendrocopos medius could best serve as source of founders for a possible reintroduction of the species in Linköping. Populations from Poland, Germany, Latvia and Lithuania were considered, taking their ecology, phylogeny and genetic diversity into account. The population’s abiotic conditions, in combination with their ability to adapt to different habitat was also considered crucial to conduce a successful reintroduction of middle spotted woodpecker in Linköping. Populations from Bialowieza and Krotoszyn in Poland, Wolfsburg in Germany and Kaunas and Marijampole in Lithuania were considered most suitable to contribute with founders. Since the middle spotted woodpecker could work as a flagship species for old and open oak stands, a reintroduction of the species could turn up the awareness for nature conservation, species conservation and biodiversity.

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Tayler, Sally. "Composition and activity of bacterial populations found on decaying stonework." Thesis, University of Portsmouth, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.304908.

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Lord, Linda K. "Epidemiological study of Ohio animal shelters and lost and found pet population issues." Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1163187060.

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Taniguchi, Yukio. "Genetic Diversities among Founder Populations of the Endangered Avian Species, the Japanese Crested Ibis and the Oriental Stork in Japan." Kyoto University, 2016. http://hdl.handle.net/2433/204565.

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Kyoto University (京都大学) 0048 新制・論文博士 博士(農学) 乙第12986号 論農博第2826号 新制||農||1038(附属図書館) 学位論文||H28||N4961(農学部図書室) 32456 名古屋大学大学院農学研究科生化学制御専攻 (主査)教授祝前博明, 教授今井裕, 教授廣岡博之 学位規則第4条第2項該当

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Fohl, Jr George Christopher. "The Influence of Universal Screening Measures on the Diversity of Students Found Eligible for Gifted Education Program Services." Diss., Virginia Tech, 2021. http://hdl.handle.net/10919/103229.

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Underrepresentation among those identified for gifted programs has been a concern in the field of gifted education for over a century, affecting students of color, students with disabilities, English language learners, and economically disadvantaged students. Universal screening has emerged as a possible strategy to increase referrals of students from underrepresented populations and to produce gifted population demographics more reflective of total student enrollment. The purpose of this study was to investigate the influence of universal screening measures on the diversity of students found eligible for gifted education services. The study examined the following research questions: 1. What is the relationship between a referral source and the gifted identification of elementary school students? 2. To what extent do universal screening measures influence the diversity of students eligible for gifted education services? This study used existing referral and eligibility data of elementary school students in a medium-sized school district who were administered a universal screening measure during the 2019-2020 school year. Pearson chi-square tests with Yates' continuity correction were used to determine the existence of possible associations between referral source and gifted identification status, and Cramér's V was used as a measure of effect size. Referral rates, accuracy, and effectiveness of referral sources were also computed. Across all demographic groups, universal screeners referred more students than any other referral source, and the highest number of students identified gifted after the full gifted evaluation came from universal screener referrals. Teacher referrals and universal screener referrals produced the most diverse identified gifted results after evaluation. Universal screeners displayed the highest referral rates and were the most accurate and effective referral source across all demographic groups. This study provides the field of gifted education further research on universal screening, and the findings of this study provide educational leaders data to inform practice. Implications for school and district leaders involve multiple stakeholders and address different areas to promote diversity among the gifted student population. The implications center on parent and community engagement, professional learning, best practices in gifted education, and evaluation of gifted identification processes. Doctor of Education Historically, students of color, students with disabilities, English language learners, and economically disadvantaged students have been underrepresented in gifted programs. Universal screening has emerged as a potential practice to refer more students from underrepresented populations and consequentially identify a more diverse gifted population, but few studies exist to support adoption of the practice and to justify the financial expense and amount of instructional time devoted to administering the assessments. This study used existing data of elementary school students in a medium-sized school district who were administered a universal screening measure to investigate the influence of universal screening measures on the diversity of students found eligible for gifted education services. Possible associations between referral source and gifted status were determined, and referral rates, accuracy and identification rates, and effectiveness of various referral sources were calculated. Across demographic groups, universal screeners referred more students than any other referral source, and the highest number of students identified gifted after the full gifted evaluation resulted from these referrals. Teacher referrals and universal screener referrals were found to produce the most diverse identified gifted populations after evaluation; universal screeners displayed the highest referral rates and were the most accurate and effective referral source across all demographic groups. This study adds further research on universal screening to the field of gifted education, and the findings of this study provide educational leaders information regarding the effectiveness of universal screening to translate into institutional practice.

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Vanderberghe-Descamps, Mathilde. "Impact of oral physiology of elderly people on their food consumption; what solutions can be found to maintain nutritional status?" Thesis, Bourgogne Franche-Comté, 2018. http://www.theses.fr/2018UBFCK011/document.

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Contexte. Chez l’homme, la mise en bouche d’un aliment est l’étape ultime de la chaîne alimentaire et le début du processus de dégradation et de digestion. Avec l’âge la santé orale évolue et peut parfois rendre l’acte alimentaire difficile.Objectif. L’objectif de cette étude est de déterminer les facteurs (salivaire, dentaire, musculaire) impactant sur les dimensions physiologiques (faculté à former un bol alimentaire, libération et perception de la flaveur) de l’acte alimentaire et/ou la prise alimentaire et la corpulence des séniors. Ceci permettra de d’identifier des techniques culinaires permettant d’adapter la texture des aliments aux problèmes bucco-dentaires.Matériel et méthode. 108 séniors (>65 ans) vivant à domicile et ne présentant pas de pathologie chronique ont été recrutés et caractérisés sur la base des dimensions suivantes : santé orale (examen clinique), auto-évaluation de la santé orale, perceptions sensorielles, faculté à former un bol alimentaire, comportement alimentaire, état de santé général. En parallèle, des techniques culinaires permettant d’améliorer la texture de la viande ont été testées. Leur efficacité a été évaluée via des mesures rhéologiques et la perception du confort en bouche par les séniors eux-mêmes.Résultats et conclusion. L’analyse multidimensionnelle des données montre que les facteurs de santé orale (dentition, salivation, force musculaire) jouent des rôles différents dans les processus de mastication et de prise alimentaire chez les personnes âgées. De plus, l’étude du confort en bouche a permis de sélectionner des techniques culinaires optimisant la tendreté et la jutosité de la viande. Ces résultats permettront de développer une offre alimentaire adaptée aux troubles oraux survenant avec l’âge Context. In human, oral food intake is the ultimate stage of food supply chain and the beginning of food disintegration and the digestion process. During aging, the oral health changes and sometimes eating food can be a real challenge as food can be hard to masticate, humidify or swallow.Objective. The aim of the present study is to determine which oral factors (salivary, dental, tongue strength) have an impact on physiological – ability to form a food bolus – and psychological – pleasure to eat – dimensions of food oral processing in order to select culinary techniques and help elderlies maintaining an appropriate protein intake in spite of the occurrence of poor oral health.Material and method. Resting and stimulated salivary flow, oral status, the ability to form a food bolus, the pleasure induced by food consumption and the nutritional status were measured on 108 elderly people (65-92 years old, living at home, with no acute pathology at the time of the study). In parallel, culinary technics that aimed at improving meat texture were developed and evaluated throughout physical measurements and oral comfort assessment by the elderly volunteers.Results and conclusion. Multivariate analysis highlighted the fact that oral factors (salivary, dental, muscular) play different roles in food oral processing and eating behavior in elderly people. Moreover, the assessment of oral comfort on the culinary technics showed that some technics improve significantly meat tenderness and juiciness. Those results will help the development of food offer tailored to elderly people with or without oral health impairments

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McGrath, Michelle A. "The use of three-dimensional motion analysis to determine whether quantitative criteria can be found for the Prechtl's qualitative assessment method of general movement classifications of writhing and fidgeting in the normative infant population." Thesis, Queensland University of Technology, 2018. https://eprints.qut.edu.au/119181/1/Michelle_McGrath_Thesis.pdf.

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This novel, preliminary study developed an infant 3DMA technical protocol to collect infant movement data using the latest three-Dimensional Motion Analysis technology. The collected data were used to quantify Prechtl's General Movements Assessment (GMsA) classifications using mathematical pattern recognition techniques, in a small cohort of healthy full term infants. These mathematical pattern recognition techniques included Fourier transform analysis, Cross Correlation and Fuzzy entropy. Fuzzy entropy is a measure of regularity in time series data and was found for this cohort to be the most useful mathematical pattern recognition technique to separate GMsA movement classifications.

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Haddad, N., S. Fuchs, H. R. Hepburn, and S. E. Radloff. "Apis florea in Jordan: source of the founder population." 2009. http://hdl.handle.net/10962/d1011047.

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A recent isolated population of Apis florea has been reported from Aqaba in Jordan at the Red Sea, consisting of numerous colonies within a still limited range which apparently is expanding. This region is about 1500 km apart from its next occurrences in Sudan where it had been introduced and first detected in 1985 and about 2000 km apart from its next natural occurrences in Iran and Oman. These bees apparently have been imported by human transport, most likely by ship. This new location thus represents a major jump in the progression of the species still to fill a wide area of possible locations offering adequate living conditions. Here we attempt to track the possible origin of this new population by morphometric methods. This analysis indicated closest relation to A. florea from Oman, thus being the most likely source of this population.

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Gauvin, Héloïse. "The French Canadian founder population : lessons and insights for genetic epidemiological research." Thèse, 2015. http://hdl.handle.net/1866/14114.

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La population canadienne-française a une histoire démographique unique faisant d’elle une population d’intérêt pour l’épidémiologie et la génétique. Cette thèse vise à mettre en valeur les caractéristiques de la population québécoise qui peuvent être utilisées afin d’améliorer la conception et l’analyse d’études d’épidémiologie génétique. Dans un premier temps, nous profitons de la présence d’information généalogique détaillée concernant les Canadiens français pour estimer leur degré d’apparentement et le comparer au degré d’apparentement génétique. L’apparentement génétique calculé à partir du partage génétique identique par ascendance est corrélé à l’apparentement généalogique, ce qui démontre l'utilité de la détection des segments identiques par ascendance pour capturer l’apparentement complexe, impliquant entre autres de la consanguinité. Les conclusions de cette première étude pourront guider l'interprétation des résultats dans d’autres populations ne disposant pas d’information généalogique. Dans un deuxième temps, afin de tirer profit pleinement du potentiel des généalogies canadienne-françaises profondes, bien conservées et quasi complètes, nous présentons le package R GENLIB, développé pour étudier de grands ensembles de données généalogiques. Nous étudions également le partage identique par ascendance à l’aide de simulations et nous mettons en évidence le fait que la structure des populations régionales peut faciliter l'identification de fondateurs importants, qui auraient pu introduire des mutations pathologiques, ce qui ouvre la porte à la prévention et au dépistage de maladies héréditaires liées à certains fondateurs. Finalement, puisque nous savons que les Canadiens français ont accumulé des segments homozygotes, à cause de la présence de consanguinité lointaine, nous estimons la consanguinité chez les individus canadiens-français et nous étudions son impact sur plusieurs traits de santé. Nous montrons comment la dépression endogamique influence des traits complexes tels que la grandeur et des traits hématologiques. Nos résultats ne sont que quelques exemples de ce que nous pouvons apprendre de la population canadienne-française. Ils nous aideront à mieux comprendre les caractéristiques des autres populations de même qu’ils pourront aider la recherche en épidémiologie génétique au sein de la population canadienne-française. The French Canadian founder population has a demographic history that makes it an important population for epidemiology and genetics. This work aims to explain what features can be used to improve the design and analysis of genetic epidemiological studies in the Quebec population. First we take advantage of the presence of extended genealogical records among French Canadians to estimate relatedness from those records and compare it to the genetic kinship. The kinship based on identical-by-descent sharing correlates well with the genealogical kinship, further demonstrating the usefulness of genomic identical-by-descent detection to capture complex relatedness involving inbreeding and our findings can guide the interpretation of results in other population without genealogical data. Second to optimally exploit the full potential of these well preserved, exhaustive and detailed French Canadian genealogical data we present the GENLIB R package developed to study large genealogies. We also investigate identical-by-descent sharing with simulations and highlight the fact that regional population structure can facilitate the identification of notable founders that could have introduced disease mutations, opening the door to prevention and screening of founder-related diseases. Third, knowing that French Canadians have accumulated segments of homozygous genotypes, as a result of inbreeding due to distant ancestors, we estimate the inbreeding in French Canadian individuals and investigate its impact on multiple health traits. We show how inbreeding depression influences complex traits such as height and blood-related traits. Those results are a few examples of what we can learn from the French Canadian population and will help to gain insight on other populations’ characteristics as well as help the genetic epidemiological research within the French Canadian population.

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Zhang, Jian. "Linkage disequilibrium mapping by the decay of haplotype sharing in a founder population /." 2001. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:3019976.

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Neumann, P., S. E. Radloff, and H. R. Hepburn. "Parasitic Cape bees in the northern regions of South Africa: source of the founder population." 2002. http://eprints.ru.ac.za/334/1/sajs_hepburn_parasitic_cape_bees.pdf.

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Multivariate discriminant analyses of nine standard morphometric characters of honeybee workers were used to track the origin of a social parasitic pseudo-clone of thelytokous laying workers that have invaded colonies of Apis mellifera scutellata in South Africa. Twenty social parasitic workers were sampled from both of two infested A. m. scutellata colonies at two distant apiaries (Graskop and Heilbronn, about 390 km apart) and compared with data obtained from 80 colonies in four different geographical zones (zone I: thelytokous A. m. capensis morphocluster; zone II: natural thelytokous hybrids between A. m. capensis and A. m. scutellata; zone III: thelytokous A. m. scutellata morphocluster; zone IV: an arrhenotokous A. m. scutellata morphocluster). Thelytokous laying workers occur naturally in zones I-III. Highly significant morphometric differences were found among the bees in the four zones. The data support the conclusion that the social parasitic workers belong to the thelytokous A. m. capensis morphocluster. It is most likely that the social parasitic workers originated from the heart of the Cape bee's distribution range in the Western Cape region in zone I. Morphometric analysis makes it feasible to restrict the possible origin of the social parasitic workers from the natural distribution range of thelytoky (approximately 240 000 km2) down to about 12 000 km2, which represents a resolution capacity of about 95%.

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Johar, Angad Singh. "Candidate Sequence Variants for Polyautoimmunity and Multiple Autoimmune Syndrome from a Colombian Genetic Isolate: Implications for Population Genetics." Phd thesis, 2018. http://hdl.handle.net/1885/148841.

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Autoimmunity is an immunological disorder whereby patients have lost immunological tolerance to self-antigen. It has extreme financial and socioeconomic burden with costs of over 100 billion dollars in the USA alone, and an estimated prevalence of 9.4%, and evidence indicates that this estimate has increased at a rate of 5% per year for the past 3 years. These phenotypes can be manifested in more severe forms through polyautoimmunity, whereby patients are carrying 2 or more autoimmune conditions. In addition to that, there is also the most extreme phenotype of autoimmunity known as the Multiple Autoimmune Syndrome (MAS), consisting of cases where patients have 3 or more autoimmune diseases. These extreme phenotypes are extremely important for genetic research as will be elaborated upon in this thesis. For more than 20 years, pedigrees from the world’s largest known genetic isolate, from the Paisa region of Colombia have been ascertained and thoroughly followed by Dr. Juan-Manuel Anaya and Dr. Mauricio Arcos-Burgos. This population has maintained its status as a genetic isolate since the 16th century, during the early colonization by the Spanish Conquistadors. In this thesis, our attempts in identifying potential candidate variants potentially underpinning the genetic etiology of autoimmune conditions in this population is facilitated by the fact that families are derived from individuals carrying extreme phenotypes, from familial cohorts where genetic homogeneity is maximized. Candidates are identified in both sporadic as well as familial cases. This is primarily achieved through combination of linkage analysis and association tests for both rare and common variants, derived from variant-calling pipelines and that had undergone quality control, filtering and functional annotation, via bioinformatic anlayses. Genes harbouring variants with significant evidence of linkage and association were primarily involved in negative regulation of apoptosis, phagocytosis, regulation of endopeptidase activity, response to lipopolysaccharides and plasminogen urokinase receptor activity. These findings, that were obtained by utilizing the combinations of statistical as well as network-based analyses have relevant potential implications in autoimmunity, and can be further supported with additional studies.

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Bourassa, Cynthia. "Découverte d'un gène causant une ataxie spastique héréditaire dominante dans la population de Terre-Neuve." Thèse, 2012. http://hdl.handle.net/1866/7061.

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Les ataxies spastiques héréditaires forment une famille hétérogène de désordres qui ont des points communs avec les ataxies héréditaires et les paraplégies spastiques héréditaires. Un de ces éléments est une ataxie, soit une difficulté de coordination des membres souvent due à un dommage au cervelet. L’autre est une spasticité des membres inférieurs, souvent due à des dommages à la voie cortico-spinale. Une seule ataxie spastique à hérédité autosomique dominante a été rapportée dans la littérature, et il s’agit de SPAX1. À l’aide de trois familles de Terre-Neuve présentant ce phénotype, le locus a été identifié en 2002. Dans ce mémoire, c’est de la découverte du gène causal dont il est question. La mutation a été trouvée dans le gène VAMP1, qui encode la protéine synaptobrévine 1, une protéine synaptique impliquée dans l’exocytose des neurotransmetteurs. Il est aussi question de la caractérisation fonctionnelle de la mutation sur l’ARN et des conséquences possibles sur la protéine, concordant avec les symptômes de la maladie. Hereditary spastic ataxias comprise a family of heterogeneous disorders resembling both hereditary ataxias and hereditary spastic paraplegias. The similar symptoms are ataxia, which is a problem with limb coordination due to cerebellar damage, and lower-limb spasticity due to corticospinal tract degeneration. Only one spastic ataxia inherited in an autosomal dominant fashion has been reported in the literature: SPAX1. The locus was identified in 2002 using three families from Newfoundland with the specific phenotype. This thesis reports the discovery of the causative mutation in the VAMP1 gene, which encodes VAMP1/synaptobrevin 1, a synaptic protein involved in neurotransmitter exocytosis. Experiments characterizing the effect of the mutation on RNA were conducted, leading to a possible molecular explanation of the symptoms.

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Nullmeier, Jens. "The Coalescent in Boundary-Limited Range Expansions." Doctoral thesis, 2014. http://hdl.handle.net/11858/00-1735-0000-0023-9903-5.

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Bhérer, Claude. "Ramifications génétiques et démographiques de l'effet fondateur québécois." Thèse, 2014. http://hdl.handle.net/1866/11846.

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Les événements fondateurs et les expansions territoriales peuvent promouvoir une cascade de changements génétiques et ont ainsi pu jouer un rôle important au cours de l’histoire évolutive de l’Homme moderne. Or, chez les populations humaines, les conséquences évolutives et la dynamique démographique des processus de colonisation demeurent largement méconnues et difficiles à étudier. Dans cette thèse, nous avons utilisé les généalogies de la population fondatrice canadienne-française ainsi que des données génomiques pour étudier ces questions. Les analyses génomiques et généalogiques, remarquablement concordantes, ont dévoilé un nouveau portrait détaillé de la structure de la population du Québec, incluant un continuum de diversité génétique dans l’axe ouest/est et des sous-populations significativement différenciées. L’analyse de l’immigration fondatrice a montré que virtuellement tous les Canadiens français sont métissés. Allant à l’encontre d’une prétendue homogénéité génétique de la population, nos résultats démontrent que le peuplement des régions a engendré une rapide différentiation génétique et expliquent certaines signatures régionales de l’effet fondateur. De plus, en suivant les changements évolutifs dans les généalogies, nous avons montré que les caractéristiques des peuplements fondateurs peuvent affecter les traits liés à la fécondité et au succès reproducteur. Cette thèse offre une meilleure compréhension du patrimoine génétique du Québec et apporte des éléments de réponse sur les conséquences évolutives des événements fondateurs. Founding events and range expansions can promote a cascade of genetic changes and may have played an important role in the evolutionary history of modern humans. Yet the evolutionary consequences and demographic dynamics of these colonization processes remain poorly documented and challenging to study in human populations. In this thesis, we used deep-rooted genealogies from the French Canadian founder population in addition to genomic data to address these questions. Genomic and genealogical analyses were remarkably concordant and revealed a new portrait of Quebec fine-scale population structure, including a continuum of genetic diversity in the west/east axis and sub-populations significantly differentiated. The analysis of the founding immigration showed that virtually all French Canadians are admixed. Contrary to the idea of homogeneity of the population, our results demonstrate that the regional settlement histories led to a rapid genetic differentiation and explain some regional signatures of the founder effect. By monitoring evolutionary changes in real genealogies, we show that founding events impact fertility traits and reproductive success. This thesis leads to a better understanding of the genetic heritage of Quebec and provides insights on how peopling of new territories shaped human evolution.

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Sergerie, François. "Le peuplement fondateur de la région de Lotbinière et ses conséquences démogénétiques." Thèse, 2010. http://hdl.handle.net/1866/4836.

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Un effet fondateur survient lorsqu’un petit nombre d’immigrants forment une nouvelle population et qu’ainsi les descendants ont une majorité de gènes provenant de ces quelques ancêtres. L’effet fondateur québécois, qui résulte de l’établissement de quelques milliers d’immigrants français aux XVIIe et XVIIIe siècles, est bien documenté. Mais des effets fondateurs régionaux ont aussi été identifiés. Ce mémoire de maîtrise vise à déterminer si un effet fondateur régional est à l’oeuvre dans la région de Lotbinière (Chaudière-Appalaches), dont le peuplement initial remonte à la fin du XVIIe siècle. Le fichier BALSAC et le Registre de la population du Québec ancien ont permis de constituer deux groupes de descendants, 715 individus mariés à la fin du XVIIIe siècle, et 60 autres mariés à la fin du XXe siècle. Par généalogies ascendantes et descendantes, les fondateurs immigrants et régionaux de la région ont par la suite été identifiés. Les résultats indiquent que l’effet fondateur régional avait encore une forte empreinte chez le groupe de descendants du XVIIIe siècle, mais que l’impact s’atténue en ce qui concerne les descendants contemporains. L’homogénéité démontrée par les coefficients d’apparentement et l’indice de contribution génétique uniforme, le petit nombre de fondateurs régionaux et le fait que 65 % des gènes contemporains étaient déjà introduits en 1800 sont des signes qui pointent vers un effet fondateur régional. Par contre, le nonisolement de la région, la proportion modérée de gènes contemporains introduits par les premiers fondateurs régionaux et les niveaux de consanguinité semblables aux autres régions du centre du Québec, incitent à nuancer cette conclusion. En fait, il y a possiblement deux Lotbinière : le Lotbinière ancien, sur la rive et le Lotbinière nouveau, dans les terres; chacun ayant son pool génique et son historique de peuplement propre. A founder effect occurs when a small number of immigrants form a new population and thus the descendants carry a majority of genes from these few ancestors. Québec’s founder effect, which resulted from the settlement of a few thousand French immigrants during the 17th and 18th centuries, is well documented. But regional founder effects have also been identified. This master’s thesis aims to determine whether a regional founder effect is at work in the Lotbinière region (Chaudière-Appalaches), where the initial settlement goes back to the 17th century. With the BALSAC database and the Registre de la population du Québec ancien, two groups of descendants have been set up: 715 individuals married during the late eighteenth century, and 60 others married during the late twentieth century. By reconstituting ascending and descending genealogies, immigrant founders and regional founders of the area have been identified. The results indicate that the regional founder effect still had a strong footprint among the group of eighteenth century descendants, but that this impact diminishes for the contemporary descendants. The homogeneity demonstrated by kinship coefficients and the founder’s uniform number, the small number of regional founders and the fact that 65 % of contemporary genes were already introduced in 1800 are signs that point to a regional founder effect. However, the nonisolation of the region, the moderate proportion of contemporary genes introduced by the first regional founders and inbreeding levels which are similar to other regions of central Quebec, suggest a less straightforward conclusion. In fact, there are possibly two Lotbinière: the old Lotbinière, on the river bank, and the new Lotbinière, inland, each one having its own gene pool and settlement history.

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Poirier, St-Georges Emmanuelle. "Exclusion de liaison génétique au locus SPAX2 de cas canadiens-français d’ataxie spastique." Thèse, 2011. http://hdl.handle.net/1866/6081.

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Les ataxies héréditaires sont des désordres neuro-dégénératifs qui causent une ataxie comme symptôme primaire; soit une perte de coordination des mouvements volontaires, un sens de l’équilibre déficient et un trouble à la motricité. Elles forment un groupe cliniquement et génétiquement hétérogène. De ce fait, de nombreuses classifications existent basées sur différents critères. Cependant, le consensus actuel veut que le mode de transmission soit le critère premier de classement. On estime la prévalence mondiale des ataxies héréditaires à 6/100 000 bien que ce nombre diffère entre régions. C’est le cas du Québec où la structuration historique du bassin génétique canadien-français a menée à des effets fondateurs régionaux, ce qui a eu comme conséquence de hausser la prévalence régionale de certaines maladies. L’Acadie est également une région canadienne-française avec des effets fondateurs où le taux de prévalence de certaines ataxies héréditaires est plus élevé. Nous avons recruté huit familles canadiennes-françaises provenant de diverses régions du Québec, ayant un lien génétique plus ou moins rapproché avec l’Acadie, dans lesquelles nous avons observé dix cas d’une forme d’ataxie spastique autosomique récessive relativement légère qui a résistée à l’analyse des gènes d’ataxies connues. Nous avons émis l’hypothèse d’être en présence d’une nouvelle forme d’ataxie à effet fondateur pour la population canadienne-française. Afin d’identifier le gène muté responsable de cette ataxie, un criblage génomique des marqueurs SNP pour les individus recrutés fut effectué. Puis, par cartographie de l’homozygotie, une région de 2,5 Mb fut identifiée sur le chromosome 17p13 dans une famille. Une revue de la littérature nous a permis de constater, qu’en 2007, quatre familles nord-africaines atteintes d’une ataxie dénommée SPAX2 qui présentaient des manifestations cliniques semblables avaient déjà été liées au même locus sur le chromosome 17. Afin de supporter notre hypothèse que les malades étaient porteurs de deux copies de la même mutation fondatrice et de cartographier plus finement notre région d’intérêt, les haplotypes de tous les atteints de nos huit familles furent étudiés. Nous avons établie qu’un intervalle de 200 kb (70 SNP), soit du marqueur rs9900036 à rs7222052, était partagé par tous nos participants. Les deux gènes les plus prometteurs des 18 se trouvant dans la région furent séquencés. Aucune mutation ne fut trouvée dans les gènes SLC25A11 et KIF1C. Par la suite, une analyse de liaison génétique stricte avec calcul de LOD score nous a permis d’exclure ce locus de 200 kb comme étant celui porteur du gène muté causant l’ataxie dans la majorité de nos familles. Nous avons donc conclus que malgré qu’une famille soit homozygote pour une grande région du chromosome 17, l’absence d’Informativité des marqueurs SNP dans la région de 200 kb fut responsable de l’apparent partage d’haplotype homozygote. Le travail reste donc entier afin d’identifier les mutations géniques responsables de la présentation ataxique chez nos participants de souche acadienne. Hereditary ataxias are neurodegenerative disorders which share ataxia as common feature is manifested by a decrease in limb coordination, imbalance and an unsteady gait. They consist in a clinically and genetically heterogeneous group. Many ataxia classifications have been proposed, however, the current consensus is to first characterize them according to their mode of transmission. Hereditary ataxias as a whole have a prevalence of 6/100 000, with variable estimation between country and region. In the Province of Quebec where the French Canadian genetic pool can be seen has a mosaic of regional gene pools there is clear differences in local variation in the prevalence of different ataxias. Acadia is also a French Canadian region with a history of many founder effects and a higher prevalence for certain hereditary ataxias. We recruit 8 French Canadian families from Quebec and with genealogical links with Acadia in which 10 cases manifest a presumably relatively mild autosomal recessive spastic ataxia of unknown etiology. The shared phenotype and Acadian background raised the possibility that they suffered from a new form of ataxia with a founder effect. To identify the mutated gene causing this ataxia, the individuals recruited were genotyped. By homozygosity mapping, a region of 2,5 Mb was identified in one family on chromosome 17p13. A literature review established that in 2007 four North Africans families segregating also a mild spastic ataxia were linked to the same locus on chromosome 17. To support our hypothesis that our patients were carrier of the same founder mutation we look closer at their haplotype in the region. We defined an interval of 200kb (70 SNP) between markers rs9900036 and rs7222052 shared by all affected cases. The two most promising gene in the interval were sequenced. No mutation was found in SLC25A11 and KIF1C. Thereafter a linkage analysis by LOD score excluded the candidate interval of 200 kb in the majority of our families. We conclude that even if in one family exists a large homozygous region on chromosome 17, the lack of informative SNP in the 200 kb region was responsible for the apparent sharing rather than they shared a common mutation. Further work will be necessary to identify the mutate gene causing the ataxia presentation in these cases of mild spastic ataxia.

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Simoneau, Marie-Eve. "Étude démogénétique de la population canadienne française de l'île de Montréal." Thèse, 2008. http://hdl.handle.net/1866/7723.

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Guterman, Mark. "Nhe6 and Nhe9 are sodium hydrogen exchangers found on separate mobile endosome populations in neuronal dendrites." Thesis, 2013. http://spectrum.library.concordia.ca/977790/1/Guterman_MSc_F2013.pdf.

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This dissertation reports the endosomal locations of NHE6 and NHE9, sodium hydrogen exchangers that contribute to pathogenesis of Autism Spectrum Disorders (ASDs) within dendrites of cultured hippocampal neurons. ASDs are debilitating, neurological disorders characterized by deficient social interaction; obsessive, repetitive behaviors; and often accompanied by mental retardation, epilepsy, and attention deficit hyperactivity disorder (ADHD). For normal brain function to occur neurons form circuits at synapses and their size and strength change based on use, known as synaptic plasticity. Disruption of synaptic plasticity is thought to underlie ASDs. Because endocytosis is required for synaptic plasticity and the yeast ortholog of human Nhe6 and Nhe9 is known to contribute to this process, I hypothesized that Nhe6 and Nhe9 are found on endosomes in hippocampal neurons where they contribute to endocytosis and synaptic plasticity. Using fluorescence microscopy, I initially demonstrate that Nhe6 and Nhe9 are localized to different pools of endosomes with cultured HeLa cells using Rab-GTPases as markers of the endocytic pathway. Nhe6 and Nhe9 showed similar distribution within the dendrites of hippocampal neurons cultured from mice or rats whereby Nhe6 was present in Rab5 and Rab11-positive endosomes and Nhe9 was found in Rab11, Rab7, and Rab9-positive endosomes later in the pathway. Live neuron imaging revealed that both Nhe6 and Nhe9 endosomes are mobile and that Nhe9-positive endosomes appear to undergo transient fusion and fission events from Rab7, Rab9, or Rab11-positive endosomes. Together, these data imply roles for Nhe6 and Nhe9 in endosome mobility and fusion underlying endocytosis required for synaptic plasticity.

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Rosa, Michel Fernandes da. "Os Atingidos de Belo Monte: experiências de sofrimento e agravos à saúde no contexto de um megaprojeto hidroelétrico na Amazônia brasileira." Doctoral thesis, 2016. http://hdl.handle.net/10316/31193.

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Tese de doutoramento em Sociologia, apresentada à Faculdade de Economia da Universidade de Coimbra A presente tese consiste em um estudo sociológico a partir do caso da Usina Hidroelétrica Belo Monte, em construção no Estado do Pará, na Amazônia brasileira. O objetivo deste estudo foi dedicar um olhar para a questão da saúde a partir da perspectiva das populações atingidas pelo megaprojeto hidroelétrico. O trabalho inicia com uma apresentação do histórico dos projetos de barramento do rio Xingu, em meados dos anos 1970. Dos primeiros estudos da bacia hidrográfica do Xingu até o início da obra de Belo Monte passaram-se aproximadamente trinta anos e, durante esse período, muitas polémicas e disputas envolveram as populações atingidas, políticos, intelectuais, artistas, cientistas, ativistas e movimentos sociais. Também é discutido nesta tese o modelo de desenvolvimento económico brasileiro, para se compreender como se dá a opção pela construção de grandes projetos de infraestrutura, como é o caso de Belo Monte. A partir dessa primeira abordagem ao megaprojeto, passo a dar ênfase à perspectiva das populações atingidas por Belo Monte. Para tanto, foi necessário, primeiramente, conhecer melhor o universo de populações atingidas, compostas por populações urbanas, rurais, comunidades ribeirinhas e indígenas. Através do trabalho empírico realizado em Brasília/DF e Altamira/PA, foi possível conhecer e reconhecer a diversidade dessas populações e, assim identificar algumas questões importantes que não foram objeto de debate com o poder público e o empreendedor. É o que Boaventura de Sousa Santos (2006) chama de produções de não existência, ou invisibilidades. A utilização da matriz teórica das epistemologias do Sul (Santos, 2002) permitiu o reconhecimento dessas invisibilidades, isto é, permitiu ver como as alterações no ambiente e nos modos de vidas das populações atingidas por Belo Monte afetam a saúde e a qualidade de vida destas. É a partir dessa lente que se dedica o olhar para a saúde das populações atingidas, e a problematização dessa questão é realizada nesta tese tendo como protagonistas as próprias populações atingidas. Assim foi identificado como um dos problemas relevantes decorrentes da construção da Usina Hidroelétrica Belo Monte a relação entre o sofrimento sentido pelas populações atingidas e o surgimento de agravos à saúde. O sofrimento difuso é um conceito desenvolvido por Valla (2001) que será discutido nesta tese na medida em que é constatado como uma consequência de Belo Monte invisibilizada. Isto porque não foi previsto ou discutido como uma possibilidade, nem no Estudo de Impacto Ambiental (EIA), nem no seu respectivo Relatório de Impacto Ambiental (Rima). Também não foi percebido como uma situação merecedora de atenção por parte do órgão fiscalizador responsável pela conceção das licenças que permitiram Belo Monte ser construída, o Ibama. Ainda, a relação entre o sofrimento e os agravos à saúde das populações atingidas não foi alvo de políticas públicas na área da saúde pública. Dessa forma, pretende este trabalho contribuir para a discussão sobre a saúde das populações atingidas pelo megaprojeto Belo Monte, a partir do reconhecimento das populações atingidas como detentoras e produtoras de conhecimento relevante. ~This thesis consists of a sociological study from the case of Belo Monte Hydroelectric Power Plant, under construction in the State of Pará, in the Brazilian Amazon. The aim of this study was to dedicate a look at the issue of health from the perspective of the people affected by hydroelectric megaproject. The work begins with a presentation of the history of the Xingu River dam projects in the mid-1970s From the first studies of the watershed of the Xingu to the early work of Belo Monte it took about thirty years and during this period, many controversies and disputes involving the populations concerned, politicians, intellectuals, artists, scientists, activists and social movements. It is also discussed in this thesis the Brazilian model of economic development, to understand how is the option for the construction of large infrastructure projects, such as the case of Belo Monte. From this first approach to megaproject, then I give emphasis to the perspective of populations affected by Belo Monte. Therefore, it was necessary, firstly, to know the universe of affected populations, composed of urban, rural populations, coastal communities and indigenous people. Through the empirical work done in Brasilia / DF and Altamira / PA, it was possible to know and recognize the diversity of these populations and thus identify some important issues that were not subject to discussion with the government and the entrepreneur. It's what Boaventura de Sousa Santos (2006) calls invisibilities. Using the theoretical framework of South epistemologies (Santos, 2002) allowed the recognition of these invisibilities, allowed to see how changes in the environment and ways of life of the populations affected by Belo Monte affect the health and quality of life of that people. It is from this lens that is dedicated to looking at the health of the populations, and the questioning of this issue is carried out in this thesis having as protagonists the affected populations themselves. Thus it was identified as one of the relevant issues arising from the construction of the Belo Monte Hydroelectric Plant the relationship between the suffering experienced by the affected populations and the emergence of health problems. The diffuse suffering is a concept developed by Valla (2001) which will be discussed in this thesis since it is found as a result of Belo Monte. This is because it was not planned or discussed as a possibility, or the Environmental Impact Study (EIA), or in their respective Environmental Impact Report (RIMA). It was also not perceived as a worthy position of attention by the supervisory body responsible for the design of the licenses that allowed Belo Monte is built, the Ibama. Also, the relationship between suffering and health problems of the affected population was not the target of public policies in the field of public health. Thus, this work aims to contribute to the discussion on the health of populations affected by Belo Monte mega-project, from the recognition of the people affected as having relevant knowledge. Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) - Nº BEX 1749-13-7

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MacLeod, Suzanne. "From the "rising tide" to solidarity: disrupting dominant crisis discourses in dementia social policy in neoliberal times." Thesis, 2014. http://hdl.handle.net/1828/5213.

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As a social worker practising in long-term residential care for people living with dementia, I am alarmed by discourses in the media and health policy that construct persons living with dementia and their health care needs as a threatening “rising tide” or crisis. I am particularly concerned about the material effects such dominant discourses, and the values they uphold, might have on the collective provision of care and support for our elderly citizens in the present neoliberal economic and political context of health care. To better understand how dominant discourses about dementia work at this time when Canada’s population is aging and the number of persons living with dementia is anticipated to increase, I have rooted my thesis in poststructural methodology. My research method is a discourse analysis, which draws on Foucault’s archaeological and genealogical concepts, to examine two contemporary health policy documents related to dementia care – one national and one provincial. I also incorporate some poetic representation – or found poetry – to write up my findings. While deconstructing and disrupting taken for granted dominant crisis discourses on dementia in health policy, my research also makes space for alternative constructions to support discursive and health policy possibilities in solidarity with persons living with dementia so that they may thrive. Graduate 0452 0680 0351 macsuz@shaw.ca

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Dissertations / Theses on the topic 'Founder population'

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