Qualitative assessment of cDNA microarray gene expression data using detrended fluctuation analysis

A number of microarray studies assume gene expression data to be independent of one another. In this report, we provide evidence of correlation in cDNA microarray gene expression data using classical power spectral analysis and the sophisticated detrended fluctuation analysis (DFA). Such correlations are shown to be an outcome of gene's position on the arrays and immune to pre-processing procedures such as normalization. The results presented encourage DFA as a tool for qualitative assessment of microarray gene expression data prior to inferring differential gene expression.