Unrestricted Access


The Nucleotide database is a collection of sequences from several sources, including GenBank, RefSeq, TPA and PDB. Genome, gene and transcript sequence data provide the foundation for biomedical research and discovery.


All NCBI databases and databanks, as wells as items on the NCBI Bookshelf, are covered in the NCBI Helf Manual.  A link is located in the footer at the bottom of each page or directly at 

User tools and features

Nucleotide is accessed like any other Entrez database, namely by

  • querying on any word,
  • restricting the query term to a certain field, or
  • applying filters or properties

A Quick Start Guide for searching the database is available on the home page.  It is written in an FAQ style and provides users will illustrated answers to common questions.  A direct link to the guide is found at .

Dates covered

Most current information available.

Updating frequency

As new information is discovered.


PubMed, published journal literature, genetics/genomics databanks.

Type of coverage

Information from published journal literature, drug information monographs, and published reports.

Producer/content provider

National Center for Biotechnology Information (NCBI)

Vendor/electronic presentation provider

National Center for Biotechnology Information (NCBI)