Figure 1.

The use of systems biology approaches has increased dramatically in the past 20 years. (A) Annual number of publications available on PubMed that contain the keywords “ChIP-seq,” “RNA-seq,” “Metabolomics,” “Proteomics,” and/or “Microarray.” These numbers were obtained directly from PubMed’s “Results by Year” section. (B) A Boolean search was used to filter the number of publications containing the chosen keyword combined with the term “circadian,” “clock,” or both. Both plots depict an increase in the use of functional genomics approaches in biology over the past 5 years, in particular the use of RNA-seq, ChIP-Seq, and metabolomics.