Metodos estatisticos para seleção de genes diferencialmente expressos a partir de dados de arranjos de DNA : aplicação a analise da expressão genica induzida em cana-de-açucar por deficiencia de fosfato / Statistical methods for the selection of differentially expressed genes from DNA array data : application to the analysis of the gene expression induced in sugarcane by phosphate deficiency

AUTOR(ES)

Rodrigo Drummond Couto Duarte

DATA DE PUBLICAÇÃO

2006

RESUMO

DNA arrays are a powerful technique for monitoring gene expression in large scale. However, the great amount of data generated by this kind of experiment requires a statistical treatment adequate to its characteristics. An important application of DNA arrays is the identification of differentially expressed genes in different RNA samples. This selection demands refined statistical tests, able of distinguish among the great number of genes usually present in the arrays those which expression is significantly different. In this work, we have developed algorithms for the analysis of DNA array data, efficient in handling the usual problems in this kind of data, as the limited number of replicates. When applied to data simulations the developed algorithms showed to be competitive with other methods of analysis described in the literature and widely used, overperforming them in some situations. The application of these algorithms was also demonstrated in an experiment devoted to the identification of sugarcane genes differentially expressed in response to phosphate deficiency. Phosphorous is an essential macronutrient, absorbed by plants mostly in the form of inorganic phosphate (Pi). The phosphate deficiency is frequent in the nature, especially in the acid soils of tropical and subtropical areas. Because of the great economical importance of sugarcane, the identification of genes that are differentially expressed in response to phosphate deficiency in this species is of great scientific and agronomic interest. Clustering algorithms were also applied to the expression data obtained in the experiment, identifying patterns of gene expression in the different stages of the sugarcane response to the stress, thus providing an additional characterization of it. In the future, the results of this work can lead to the development of sugarcane cultivars that have better performance in phosphate deficient soils, what would be of great agronomic interest

ASSUNTO(S)

data analysis dna arrays sugarcane analise de dados quantitativos cana-de-açucar arranjos de dna fosfato phosfhate deficiency

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