Thesis (Ph.D.)--Ohio University, November, 2004. / Title from PDF t.p. Includes bibliographical references (p. 94-101)

Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (p. 64-73).

Magister Scientiae - MSc / The aim of this study was to investigate the forensic usefulness of various Y-chromosome short tandem repeat loci among South African sub-populations. Three different sets of Y-chromosome short tandem repeat loci were chosen for investigation. / South Africa

Apolipoprotein E (apoE) is a lipid transport protein which plays a key role in lipid metabolism. In addition to the well known polymorphic coding alleles epsilon2, epsilon3 and epsilon4, APOE promoter single nucleotide polymorphisms (SNPs) have also been reported to modify disease susceptibilities in humans. / In a case-control study involving 710 Chinese type 2 diabetes and 198 non-diabetic subjects, genotyping of three SNPs (-491A/T, -219G/T and +113G/C) within the APOE proximal promoter identified that -491A was associated with increased risk for type 2 diabetes in women (OR=2.44, 95%CI=1.15-5.19, p=0.017). However, the three tested SNPs were not associated with the risk of diabetic nephropathy (DN). Yeast one-hybrid screening of the human brain cDNA library using the polymorphic DNA sequences spanning the APOE promoter -491 site as the 'baits' identified one of the interacting transcription factors being the activating transcription factor 4 (ATF4). Electrophoretic-mobility-shift assay confirmed the physical interaction of the purified recombinant ATF4 protein and APOE promoter -491 A/T spanning region (-521 to -461). The binding of ATF4 to the -491T-containing sequence was stronger than that of the -491A-containing sequence. Chromatin immunoprecipitation (ChIP) assay further confirmed the interaction between ATF4 and APOE promoter -491-spanning region in vivo. The functional significance of APOE -491A/T polymorphism was supported by the dual-luciferase reporter assay showing that -491 A to T single nucleotide substitution significantly decreased the activity of the cloned APOE promoter (-1019 to +407) in human kidney (293), liver (WRL-68) and astrocyte (U-87) cell lines. Further analysis showed that ATF4 over-expression significantly down-regulated the activities of the cloned APOE promoter. The suppression of ATF4 on APOE promoter with -491A allelic form was significantly stronger than that with -491T allelic form in 293 cells (p<0.05). Interestingly, overexpression of recombinant ATF4 stimulated endogenous APOE transcription by about 10% in WRL-68 cells. / In conclusion, APOE promoter -491A/T polymorphism modifies the risk of type 2 diabetes in Hong Kong Chinese women. The -491A/T polymorphism controls APOE promoter activity and is interactive with transcription factor ATF4. / My thesis project aimed at testing two hypotheses: (1) APOE promoter SNPs associate with the risks of type 2 diabetes and diabetic nephropathy, (2) APOE promoter SNPs modify transcriptional control of the gene. / Geng, Hua. / "September 2007." / Source: Dissertation Abstracts International, Volume: 69-08, Section: B, page: 4559. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (p. 140-151). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

Frequency-dependent selection has long been a popular heuristic explanation for the maintenance of genetic diversity in natural populations. Indeed, a large body of theoretical and empirical work has already gone into elucidating the causes and consequences of frequency-dependent selection. Most theoretical work, to date, has focused either on the diallelic case, or dealt with only very specific forms of frequency-dependence. A general model of the maintenance of multiallelic genetic diversity has been lacking. Here we extend a flexible general model of frequency-dependent selection, the pairwise interaction model, to the case of multiple alleles. First, we investigate the potential for genetic variation under the pairwise interaction model using a parameter-space approach. This approach involves taking a large random sample of all possible fitness sets and initial allele-frequency vectors of the model, iterating each to equilibrium from each set of random initial conditions, and measuring how often variation is maintained, and by which parameter combinations. We find that frequency- dependent selection maintains full polymorphism more often than classic constant-selection models and produces more skewed equilibrium allele frequencies. Fitness sets with some degree of rare advantage maintained full polymorphism most often, but a variety of non-obvious fitness patterns were also found to have positive potential for polymorphism. Second, we further investigate some unusual dynamics uncovered by the parameter-space approach above. Long-period allele-frequency cycles and a small number of aperiodic trajectories were detected. We measured the number, length and domains of attraction of the various attractors produced by the model. The genetic cycles produced by the model did not have periods short enough to be observable on an ecological time scale. In a real world system, allele-frequency cycling is likely to be indistinguishable from stable equilibrium when observed over short time scales. Third, we use a construction approach to model frequency-dependent selection with mutation under the pairwise interaction model. This approach involves the construction of an allelic polymorphism by bombarding an initial monomorphism with mutant alleles over many generations. We find that frequency-dependent selection is able to generate large numbers of alleles at a single locus. The construction process generates a wide range of allele- frequency distributions and genotypic fitness relationships. We find that constructed polymorphisms remain permanently invasible to new mutants. Analysis of constructed fitness sets may even reveal a signature of positive frequency dependence. Finally, we examine the numbers and distributions of fitnesses and alleles produced by construction under the pairwise interaction model with mutation from existing alleles, using several different methods of generating mutant fitnesses. We find that, relative to more general construction models, generating mutants from existing alleles lowers the average number of alleles maintained by frequency-dependent selection. Nevertheless, while the overall numbers of alleles are lower, the polymorphisms produced are more stable, with more natural allele-frequency distributions. Overall, frequency-dependent selection remains a powerful mechanism for the maintenance of genetic variation, although it does not always work in intuitively obvious ways.

Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2003. / Includes bibliographical references (leaves 95-105). Also available in electronic version. Access restricted to campus users.

Thesis (M.Sc. Biological Sciences)--University of Waikato, 2007. / Title from PDF cover (viewed February 27, 2008) Includes bibliographical references (p. 189-199)

Thesis (Ph. D.)--University of Texas Health Science Center at Houston, School of Public Health, 2007. / Source: Dissertation Abstracts International, Volume: 68-10, Section: B, page: 6419. Advisers: Christopher I. Amos; Ralph F. Frankowski. Includes bibliographical references.

Made available in DSpace on 2014-06-11T19:33:31Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-08-20Bitstream added on 2014-06-13T19:04:33Z : No. of bitstreams: 1 boschiero_c_dr_botfmvz.pdf: 635473 bytes, checksum: feca4297f6abf36be6a9c8cf72ce1eb6 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Universidade Estadual Paulista (UNESP) / A partir de resultados de um estudo anterior, no qual foram mapeados QTLs para características de peso vivo, peso do coração e pulmões no GGA1, foi definida uma região no intervalo entre os marcadores ADL0234 e LEI0071, abrangendo 82,3 cM. Foram avaliadas três famílias de meios-irmãos paternos que compreendiam sete famílias de irmãos completos, num total de 652 F2 para as características: peso vivo aos 35 e 41 dias de idade, pesos do coração e pulmões e rendimentos de coração e pulmões. Os genótipos de seis marcadores microssatélites foram adicionados aos dez utilizados anteriormente. O mapa de ligação obtido da região compreendeu 110,8 cM com espaçamento médio entre os marcadores de 7,4 cM. Na análise de F2, em um único intervalo (LEI0146-LEI0174), compreendendo 28,8 cM, foram mapeados QTLs para todas as características estudadas, com exceção dos rendimentos de coração e pulmões. Neste intervalo estão localizados o gene IGF1 e o centrômero do cromossomo. A adição de seis marcadores confirmou os QTLs mapeados anteriormente, porém alguns em diferentes posições. A análise de meios-irmãos paternos indicou que os principais QTLs estavam segregando em apenas uma das famílias (7716), na qual cinco QTLs foram mapeados. Na análise de meios-irmãos maternos, duas famílias segregaram QTLs tanto na análise Individual como na Conjunta (7810 e 7971). As diferentes análises permitiram selecionar dois casais F1, que devem ser o alvo dos próximos estudos. Este estudo restringiu a busca por genes candidatos responsáveis pelas características de interesse a uma região de 28,8 cM (9,82 Mb) no GGA1. / Based on the results from a previous study, in which QTL for body weight, heart and lungs weights and heart and lungs percentages were mapped to GGA1, a region was defined between markers ADL0234 and LEI0071, spanning 82.3 cM. Three paternal half-sib families, comprising seven full-sib families, totaling 652 F2 were evaluated for body weight at 35 and 41 days of age, heart and lungs weights and heart and lungs yields. Genotypes of six microsatellite markers were added to those of ten previously used. The linkage map of this region spanned 110.8 cM, with average spacing of 7.4 cM between markers. In a single interval (LEI0146-LEI0174), comprising 28.8 cM, QTLs for all traits, except for heart and lungs yields were mapped in the F2 analysis. In this same interval the IGF1 gene, and the chromosome centromere, are located. The use of six additional markers confirmed the same QTLs mapped previously, but some of them, in different positions. The paternal half-sib analysis indicated that the main QTLs were segregating in one of the families only (7716), in which five QTLs were mapped. In the maternal half-sib analysis, two families segregated QTLs both, in the across and within families analyses (7810 and 7971). These analyses allowed the selection of two F1 couples to be the target for future studies. This study restricted the search for candidate genes responsible for the traits of interest to a region of 28.8 cM (9.82 Mb) in GGA1.

Orientador: Louis Bernard Klaczko / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-08T11:40:37Z (GMT). No. of bitstreams: 1 Rocha_FelipeBastos_M.pdf: 1521732 bytes, checksum: 2e105d0f1d7044bc42e2f93125f6ac49 (MD5) Previous issue date: 2007 / Resumo: Drosophila mediopunctata é uma espécie pertencente ao grupo tripunctata, que tem como traço marcante um padrão de pigmentação abdominal, sob a forma de três pintas na região mediana dos últimos tergitos. Nesta espécie, este padrão é variável, havendo indivíduos com quatro fenótipos, que vão de zero a três pintas. Já se observou que esta variação tem determinação genética, com marcada influência do cromossomo II, e alta plasticidade fenotípica em resposta à temperatura de desenvolvimento. Neste trabalho, buscou-se caracterizar parte destas duas fontes de variação. Por um lado, foram estudadas as normas de reação da pigmentação a um gradiente térmico, investigando-se classes fenotípicas contrastantes. Devido ao desenho experimental, que buscou separar os efeitos desta variável de um possível papel das inversões do cromossomo II, foi possível evidenciar um forte efeito das classes fenotípicas utilizadas sobre a resposta das estirpes ao gradiente térmico, independente do cariótipo. Foram descritos, por polinômios, dois tipos de norma de reação relacionados ao fenótipo, ambos com forma de parábola, mas diferindo em relação ao coeficiente de curvatura. O grupo de estirpes de pigmentação clara apresentou uma curva côncava e o grupo escuro uma curva convexa. A norma de reação da taxa de desenvolvimento de ovo a adulto foi caracterizada a partir do mesmo procedimento. Entretanto, apesar dos efeitos significativos do cariótipo e da classe fenotípica, a homogeneidade das normas de reação descritas por regressões lineares não possibilitou uma interpretação clara destes efeitos. A plasticidade do caráter também foi investigada quanto ao período de desenvolvimento termo-sensível. Assim, foi possível determinar a porção final da fase de pupa como o período no qual ocorre a influência da temperatura sobre o fenótipo de pintas do adulto. Por outro lado, em relação à determinação genética do caráter, foram obtidas estimativas de herdabilidade para o número de pintas abdominais, em condições quase naturais. Visando estabelecer um parâmetro de comparação com outros trabalhos, foi estimada a herdabilidade do tamanho do tórax a partir do mesmo material. Os resultados deste experimento, apresentaram grande contraste entre os dois traços: as estimativas foram baixas ou não significativas para o tamanho do tórax e, em geral, altas e significativas para o número de pintas / Abstract: Drosophila mediopunctata belongs to the tripunctata species group, which has a typical abdomen pigmentation pattern, consisting of three dark spots in the last tergites. In this species, this pattern is variable, with the phenotypes ranging from zero to three spots. It has been noted that this variation has genetical determination, with strong influence from the second chromosome, and high phenotypic plasticity in response to the developmental temperature. In this work, we attempted to describe part of these two variation sources. On one side, the pigmentation reaction norm to a thermal gradient was studied, by investigating the influence of contrasting phenotypical classes. Given the experimental design, which was planned to separate the effects of this variable from a possible influence of the second chromosome inversions, it was possible to detect a strong effect of the phenotypical classes on the lineages response to the thermal gradient, independent of the kariotype. Two types of reaction norms, related to the phenotype, were detected and described by polynomial adjustment. Both had a parabolic shape, but with different curvature coefficients. The light pigmentation lineage group showed a concave curve, and the dark group had a convex curve. The reaction norm of development rate from egg to adult was described according to the same procedure. However, despite the significant effects of the karyotype and phenotypical classes, the homogeneity of reaction norms, described by linear regression, hindered a clear interpretation of these effects. The character plasticity was also investigated in respect to the developmental thermosensitive period. Thus, it was possible to determine that the period in which the temperature influence on the adult phenotype occurs is the last portion of the pupal phase. On another side, relative to the character genetic determination, heritability estimates for the number of abdominal spots were obtained, in nearly natural conditions. Aiming to establish a comparison parameter with other studies, the heritability of thorax length was estimated based on the same material. The results of this experiment reveal a great contrast between these trait estimates: for the thorax they were low or non-significant, and, in general, for the abdominal spot number, they were high and significant / Mestrado / Genetica Animal e Evolução / Mestre em Genética e Biologia Molecular