Processing and quality control of DNA array hybridization data

Motivation: The technology of hybridization to DNA arrays is used to obtain the expression levels of many different genes simultaneously. It enables s earching for genes that are expressed specifically under certain conditions . However the technology produces large amounts of data demanding computati onal methods for their analysis. It is necessary to find ways to compare da ta from different experiments and to consider the quality and reproducibili ty of the data. Results: Data analyzed in this paper have been generated by hybridization o f radioactively labeled targets to DNA arrays spotted on nylon membranes. W e introduce methods to compare the intensity values of several hybridizatio n experiments. This is essential to find differentially expressed genes or to do pattern analysis. We also discuss possibilities for quality control o f the acquired data.