Normalization Methods for Time-Course DNA Microarray Data

Normalization is an important step in any DNA microarray analysis, with the goal of removing sources of bias that may interfere with the identification of truly differentially expressed genes. Many different normalization methods have been proposed in the literature, however, the majority are only applicable to experiments wherein two samples are compared to one another (comparator experiments).  Time-course DNA microarray experiments (and other serial types of experiments), wherein the arrays form a pseudo-continuum of expression, have become more common in recent years, with no concomitant discussion or development of appropriate normalization methods. We have developed a conceptually simple technique for normalizing DNA time-course data that we refer to as sequential normalization.