RNA profiling in circadian biology.

DNA arrays have become indispensable tools in the study of transcriptional output of the circadian clock and have enabled an increase in the number of outputs from tens to thousands. However, despite their widespread use, many challenges exist in accurately and sensitively identifying all transcriptional targets of the clock. This article discusses aspects of experimental design, including RNA-amplification strategies, data condensation methods, and other aspects that impact the use of these tools for the study of circadian biology.