The dynamic range of gene expressions depend on their ontology

In this study we investigate the correlation between the normal variation of gene expressions and their ontologies. Three sets of time-series microarray data are utilized that represent three different but typical physiological/developmental processes. We analyze the dynamic range and the variation of expression levels during these processes for genes in each of the top-level ontologies of the biological process, molecular function and cellular component, as defined by GO. Significant and consistent differences are observed. For example, transcription factors were found to have consistent narrower dynamic range of expression in all three processes. The findings will shed light on study design, statistical evaluation, and data mining of genetic data including microarray data.