GEO is a public repository that archives and freely distributes microarray, next-generation sequencing, and other forms of high-throughput functional genomic data submitted by the scientific community. In addition to data storage, a collection of web-based interfaces and applications are available to help users query and download the studies and gene expression patterns stored in GEO. Submitters are encouraged to supply MIAME compliant data.

The MIAME (Minimum Information About a Microarray Experiment) guidelines outline the minimum information that should be included when describing a microarray experiment. The six most critical elements contributing towards MIAME are :

• raw data for each hybridization
• final processed (normalized) data for the set of hybridizations in the experiment
• essential sample annotation including experimental factors and their values
• experimental design including sample data relationships
• sufficient annotation of the array
• essential laboratory and data processing protocols

Many journals require accession numbers for microarray or sequence data before acceptance of a paper for publication. GEO processing times is approximately 5 business days after completion of submission.

GEO is hosetd by the NCBI (National Center for Biotechnology Information).  A detailed documentation is available at the NCBI website. Specific recommendations for Agilent submissions are also available.