Qualitative Analysis of Gene Regulatory Networks Based on Angular Discretization

It is well known that there is a hypothesis in the analysis of gene regulatory networks, i.e., if two genes expression profiles change in a similar trend, a regulatory relationship may exists in these two genes. Therefore, the use of angular discretization to deal with gene expression data can reflect the changes of gene expression values in tendency and intensity, which makes it possible to analyze the regulatory relationship between genes qualitatively. At first, we draw a line between the neighboring gene expression data. Thus an angle between the connected line and a horizontal line is formed. Secondly, according to the defined rules of angular discretization, we discretize the angle into six states by carrying out several times of discretization operation. The six states reflect not only the trend but also the change degree of gene expression values. In the end, the genes having regulatory relationships will be identified by using the substruction and the relative frequency methods. Experimental results concerning on the Saccharomyces microarray dataset verify the validity of the proposed method.