Skip to main content

Introduction to NCBI Bioinformatics Resources: Sequence Search

A concise introduction to the various bioinformatic data available from NCBI.

BLAST Overview

BLAST Overview

NCBI provides a trademarked tool for sequence searching - Basic Local Alignment Sequence Tool (BLAST).

BLAST can be used to:

  • Find similar database records for protein or nucleic acid sequences
  • Find Conserved Domains within sequences
  • Compare and align sequences

NCBI created a good BLAST tutorial:

Comparative Genomics: Volumes 1 and 2. Bergman NH, ed; Humana Press; 2007
Chapter 9 BLAST QuickStart - David Wheeler and Medha Bhagwat

The BLAST home page: http://blast.ncbi.nlm.nih.gov/

The mathematics behind this resource are fairly complicated.  Please keep in mind that, depending on the specific search, the results may take a long time to appear.


The topics in this guide are:

BLASTP - Protein Sequence Search

BLASTN - Nucleotide Sequence Search

BLAST   - BLAST Results