Temporal and spatial distinct patterns of gene expression regulate biological processes involved in cell development, differentiation, cell cycle, death and pathology. The identification of differential expression gene between the different functional status cells has become an important content of gene research. In recent years, a variety of methods have been developed for analying differentially expressed genes, including subtractive hybridization, mRNA differential display, representational difference analysis, serial analysis of gene expression, suppression subtractive hybridization, expressed sequence tags, DNA chip, quantitative polymerase chain reaction and semiquantitative polymerase chain reaction. This manuscript reviews the two most commonly used technologies of rapid and large-scale screening for differentially expressed genes, and highlights recent applications in dental pulp studies.
