BLAST: Basic Local Alignment Search Tool

The Basic Local Alignment Search Tool (BLAST) finds regions of local similarity between sequences. The program compares nucleotide or protein sequences to sequence databases and calculates the statistical significance of matches. BLAST can be used to infer functional and evolutionary relationships between sequences as well as help identify members of gene families.

Overview

Added

March 17, 2026

Subject & domain

life-health · evolution-natural-selection

Grade range

Grade 9 (Freshman)–Grade 12 (Senior)

Page kind

Tool

Keywords

blastbasic local alignment search toolsequence similaritysequence alignmentsequence homologybioinformatics

Introduction

Overview of BLAST

  • Purpose: BLAST (Basic Local Alignment Search Tool) identifies regions of local similarity between biological sequences.
  • Functionality: It compares nucleotide or protein sequences against sequence databases and calculates the statistical significance of the matches.
  • Applications: Used to infer functional and evolutionary relationships between sequences and to identify members of gene families.
  • Platform: An official, secure United States government website.
  • Recent Updates: The latest BLAST+ release was highlighted on July 21, 2025.

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