Navegando por Assunto "polimorfismo"
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Item Caracterização da estrutura genética de populações de Caryocar brasiliense Camb. no estado de Goiás utilizando marcadores moleculares microssatélites(Universidade Federal de Goiás, 2005-08-25) Chaves, Sivany Rodrigues; Sibov, Sérgio Tadeu; http://lattes.cnpq.br/4627553641870284; Sibov, Sérgio Tadeu; Cruz, Aparecido Divino da; Chaves, Lázaro JoséThe species Caryocar brasiliense Camb. (pequizeiro) is a common tree fruitful in the Brazilian savannah (Cerrado) with great economic and social potential. The objective of this study goals the increase of information for an efficient breeding program for specie domestication and conservation. Eleven natural populations of “pequizeiro”, 30 individuals each, was sampled on five different regions of Goiás state. The genetics structure of these natural populations was analyzed based on variability at eight microsatellite loci in about 330 individuals. The number of alleles per locus it varied of 22 to 32 (mean = 28). The waited and observed heterozigosity varied of 0,843 to 0,920 and 0,546 to 0,758, respectively. Measures of genetic differentiation indicated significant differences between most populations (FST = 0,064 and RST = 0,439). RST values among samples were high and much higher than FST indicating a divergence between the model that consider alleles to be identical by descent, and the model of identity by state in these populations. Estimated number of migrants was high, Nm = 3,63 (mean), and the existence of private alleles indicated reduced gene flow and a consequently possible damage to the metapopulations structure. Significant correlation was not found between geographical distance and measure of genetic divergence, suggesting the intense gene flow in the past that joined the populations that are separated today.Item Estudo de associação do polimorfismo de base única no códon 72 do gene humano p53 e as características de pigmentação(Universidade Federal de Goiás, 2010-03-30) COSTA, Kárita Antunes; GUILLO, Lídia Andreu; http://lattes.cnpq.br/3401436781775091The p53 gene encodes a protein which has various functions such as monitoring of the cell cycle, role in repair mechanisms and apoptosis. New functions performed by this protein have been observed and studied as acting in the cascade of skin pigmentation by acting as transcription factor for genes important in this process as POMC (pro-opiomelanocortin) and MC1R (melanocortin receptor 1). Among the genetic polymorphisms, the codon 72 p53 gene is the most commonly studied and this variant has been associated with increased risk for various cancers, including skin. However, the association between this and other types of cancers has generated controversial results. The polymorphism occurs in a substitution G / C codon 72 p53 gene resulting in a change of amino acid sequence (CGC to CCC for arginine and proline). This polymorphism occurs in areas rich in proline generating morphophysiological changes as well as a difference in electrophoretic mobility of the protein. The aim of this study was to establish a possible association between the codon 72 polymorphism of p53 gene with the characteristics of pigmentation such as skin color, hair, eye and skin response after exposure to sunlight (reddening or bronze). The 96 healthy volunteers were recruited randomly and information on skin color, ability to tan and other characteristics of pigmentation were collected through a standardized questionnaire. Genomic DNA was extracted from venous blood and genotyping was performed by polymerase chain reaction (PCR). The polymorphism was investigated by photo documentation after agarose gel electrophoresis. Samples that generated doubts were confirmed by digestion with sitespecific action of the restriction enzyme BstUI. Allele frequencies of 96 volunteers to p53Arg/72 and p53Pro/72 were 67.70% and 32.30% respectively. Genotype frequencies for Arg / Arg, Arg / Pro and Pro / Pro were 50.00% 35.40% 14.60% respectively. We did not detect a significant association between reddening or tanning after sun exposure with the polymorphism (p = 0.678), on the other hand we observed an association between the genotype Pro / Pro and blue eyes / green (p = 0.01) among showing redness of the skin, demonstrating a disadvantage in relation to the sun when there is occurrence of this specific phenotype (eye color) combined with the genotype Pro / Pro.Item O polimorfismo do gene p5372(RP) no câncer de cabeça e pescoço: estudo de associação e meta-análise(Universidade Federal de Goiás, 2009-10-20) SILVA, Antonio Márcio Teodoro Cordeiro; CRUZ, Aparecido Divino da; http://lattes.cnpq.br/7868817504129985Head and neck cancer arises in the oral cavity and nearby regions, larynx, pharynx, including oropharynx, nasopharynx, and hipopharynx. Extensive epidemiologic studies have revealed that chronic tobacco smoking and alcohol consumption as the two main risk factors associated with the multifactorial etiology of head and neck cancers. Additionally, nutritional status, HPV infection, and genetic polymorphism were also related with the disease. A frequently studied polymorphism in Squamous Cell Carcinoma (SCC) of head and neck is a G-to-C SNP (Single Nucleotide Polymorphism) at codon 72 in the p53 gene, which codes for an Arg or Pro (Arginine or Proline) in P53 protein. In order to investigate the distribution and potential association of that SNP in SCC, biological samples were obtained from 331 cases of head and neck SCC from Araújo Jorge Hospital and 271 healthy control individuals from Goiânia (Brazil) population. DNA was isolated and subsequently used for PCR amplification to genotype cases and controls with respect to their p5372 SNP. Additionaly, a meta-analysis was carried out using 29 relevant case-control studies that used p5372 SNP genotyping in SCC of the head and neck. Allelic frequencies for cases were 73.3% and 27.7% for Arg and Pro, respectively. On the other hand, control allelic frequencies were 74.2% and 25.8% for Arg and Pro, respectively (p = 0.119). Genotypic frequencies were 56.8% Arg/Arg, 32.9% Arg/Pro, and 10.3% Pro/Pro for all cases. The control genotypic frequencies were 61.3% Arg/Arg, 25.8% Arg/Pro and 12.9% Pro/Pro (p = 0,137). According to the current data and meta-analysis, no association between p5372 SNP and the development of SCC of the head and neck was found. Although, the homozygous genotype Arg/Arg was found as an important oncogenic risk factor associated with the carcinoma of the oropharynx.Item Avaliação Genético-Molecular do Carcinoma das Células Escamosas da Laringe(Universidade Federal de Goiás, 2009-10-21) SILVA, Cláudio Carlos da; CRUZ, Aparecido Divino da; http://lattes.cnpq.br/7868817504129985The larynx is a structure of the upper aerodigestive tract responsible for the production of sounds as well as protecting the lower airways and helping during the normal act of swallowing. Any pathology which affects the larynx can impose several challenges that disrupt its normal physiological function, and consequently and directly resulting in reduction of the patient s quality of life. Among the different diseases that affect the larynx, cancer is one of the most serious. The squamous cell carcinoma (SCC) of the larynx is a multifactorial disease, influenced by environmental factors and individual behavioral, habits, and susceptibility. The current study describes the molecular and genetic assessment of 20 patients with the squamous cell carcinoma of the larynx. In summary, the study strategy included the analyses of the genetic polymorphism of codon 72 of the TP53, the detection and genotyping of HPV genome, assessing genomic instability (MIS and LOH) and random chromosomal imbalances using PCR and CGH approaches. Regarding to the polymorphism of the TP53 gene, arginine homozygous genotypes (p53AA) and arginine-proline heterozygous genotypes (p53PA) were found in 65% (13/20) and 35% (7 / 20) of cases, respectively. HPV genome was found in association with tumor cells in 20% of SCC cases. HPV 16, 11, and 45 were the genotypes identified. Moreover, co-infection of HPV 11 and 45 was also observed. Both samples found positive for HPV genome were associated with p53AA at the TP53 gene. Our results corroborated the data published in the literature that described an increased susceptibility to the virus-induced carcinogenesis of the larynx in arginine homozygous genotypes. Here in we report genomic instability for a panel of 8 microsatellite markers distributed in 5 chromosomes. One locus (D8S135) was found in homozygous for all cases. On the other hand, RH-92600 was not included in the analysis mainly because it was also found homozygous for most cases. We found 76.2% (244/320) of informative loci. Thus the mean frequency of MIS was 9.0% (22/244) and LOH was 6.1% (15/244). The frequency of MIS was found higher than the LOH, suggesting that the tumorigenesis of SCC of the larynx follows a mechanism of mutator phenotype. Using CGH, chromosomal gains were observed in 1q21qter. On the other hand, chromosomal losses occurred in chromosome 3p21p28, 11q23, 16p16, 16q12, 17p13pter and 22q13. The techniques of comparative genomic hybridization have improved the understanding of genetic alterations in squamous cell carcinoma of the larynx, especially for characterizing the relationship between early precursors of laryngeal carcinomas, as well as to identify genomic regions that may contain oncogenes and tumor suppressor genes involved in the tumorigenesis of this anatomical site.