Technology and application of DNA array

Recently DNA macro and micro array has just begun to use for analysis of DNA expression. The array technique allows us to analyze expression pattern of several hundreds and thousands of genes simultaneously. The array method enables us to analyze gene expression levels of each gene among different samples, however it does not provide comparative analysis of the expression level of multiple genes in a single array. Because intensity of each signal on the array is normalized by the expression intensity of several standard house keeping genes, intensity of signals of each genes among different array can be compared by the number of relative intensity based on normalization. Such characteristic feature of array allows us to analyze potential function of the genes even though function of genes are not known or well characterized.