Genotipagem seletiva e outras estratégias de amostragem no mapeamento genético e na detecção de QTL em populações F2 simuladas

• Ano de defesa: 2007
• Autor(a) principal: Barros, Willian Silva
• Orientador(a): Cruz, Cosme Damião
• Banca de defesa: Silva, Fabyano Fonseca e , Caixeta, Eveline Teixeira
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Doutorado em Genética e Melhoramento
• Departamento: Genética animal; Genética molecular e de microrganismos; Genética quantitativa; Genética vegetal; Me
• País: BR
• Palavras-chave em Português: Melhoramento genético; Estatística genômica; Mapeamento genético; Locos de caracteres quantitativos
• Palavras-chave em Inglês: Genetic improvement; Genetic mapping; Quantitative traits locos
• Área do conhecimento CNPq: CNPQ::CIENCIAS BIOLOGICAS::GENETICA::GENETICA QUANTITATIVA
• Link de acesso: http://locus.ufv.br/handle/123456789/1413

The genetic analysis at DNA level has becoming more and more efficient. Much information has been generated on the genomes of plants. Though, the main challenge refers to the integrally application of this knowledge on the effective practice of the genetic plant breeding. A considerable number of analytical studies on the mapping of the genes and QTL have been conducted. However, genotyping a great number of individuals for several markers is a limitation, in spite of the revolution caused by the introduction of techniques based on Polymerase Chain Reaction (PCR). So, there is a need for studies involving experimental strategies such as the selective genotyping, that would allow to reduce the number of genotyped individuals, but keeping the detection power of the QTL. The computer simulation has been used for either obtainment of the properties and verification of the performance by the models, methods, size and population types in the genetic mapping and QTL detection. So, a study was carried out to investigate the influence of the heritability levels, gene action, and the linkage group saturations in the genetic mapping and QTL detection. By using simulation, some F2 populations with 1,000 individuals in 36 sceneries were analyzed for phenotypic traits. Another objective was to investigate the influence of the selection intensity in samples obtained by selective genotyping of the F2 populations simulated in the genetic mapping and QTL detection. For 20% selection intensity, the results from the selective genotyping were compared to other experimental strategies for the samplings of the systematic, mixed and random types. In the first chapter, it was found that the genetic mapping was according to the simulated genome in all 3,600 F2 populations. Concerning to the QLT detection, it is observed that 20% heritability levels and the gene levels of 5 and 10% are sceneries that do not allow for an easy detection of QTL, independent from the saturation of the linkage group. In the second chapter, the linkage map differed from the expected one, when the selection intensity of the selective genotyping was 10% in many sceneries. At the other selection intensities, the recovery of the linkage map was possible as expected, even with distorted marks near to the simulated QTL. Concerning to QTL detection, the average values of the "LOD scores" in the populations with 500, 300 and 200 individuals sampled for selective genotyping were slightly lower than those found in the populations with 1,000 individuals. The results obtained from the genomic analyses in experimental strategies of the mixed sampling and selective genotyping were satisfactory. On average, they maintained linkage maps close to the expected, with high power to detecting QTL in comparison to the results obtained in both random and systematic samplings.