GEO Database

Overview

The Gene Expression Omnibus (GEO) is NCBI's public repository for high-throughput gene expression and functional genomics data. It holds hundreds of thousands of studies (Series) and millions of samples from both array-based and sequence-based experiments. For current totals see the GEO browser at https://www.ncbi.nlm.nih.gov/geo/.

When to Use This Skill

Use this skill when searching for gene expression datasets, retrieving experimental data, downloading raw and processed files, querying expression profiles, or integrating GEO data into computational analysis workflows.

Core Workflow

1. Search for relevant studies (E-utilities / Bio.Entrez) → see references/searching.md.
2. Retrieve a series with GEOparse: GEOparse.get_GEO(geo="GSE...", destdir="./data") → see references/geoparse_usage.md.
3. Extract the expression matrix via gse.pivot_samples('VALUE') (genes × samples).
4. Analyze — QC, differential expression, clustering, meta-analysis → see references/expression_analysis.md.

For bulk downloads, skip GEOparse and pull files directly over FTP → see references/data_access.md.