Sketch of GEO data organization. Platform, Sample, and Series records are created from the data supplied by submitters. These records contain: (A) a description of the array or sequencer; (B) a tab-delimited table of the array template definition; (C) a description of the biological sample and protocols to which it was subjected; (D) a tab-delimited table of processed array hybridization results; (E) links to original raw data file, or processed sequence data file; (F) a description of the overall study, study design, and citation information; (G) links for bulk downloading data for the entire study. At periodic intervals, selected records undergo further processing into curated GEO DataSet (H) and GEO Profile (I) records that help users analyze and visualize gene expression.