BLAST Heuristic Alignment

Fast sequence alignment using word-based heuristic search. Find similar sequences quickly with BLAST-like algorithm.

Alignment Details

What is BLAST Heuristic Alignment?

BLAST (Basic Local Alignment Search Tool) uses heuristic algorithms to find similar sequences quickly. Instead of comparing every position, it searches for short matching "words" (k-mers) and extends them, making it much faster than exhaustive alignment methods.

How to Use This BLAST Tool

Quick guide to find similar sequences:

  1. Paste your query sequence in the left box
  2. Add database sequences to search against
  3. Adjust word size and threshold parameters
  4. View matches and alignments automatically

When to Use

This tool is useful when you need to:

  • Search large sequence databases quickly
  • Find homologous sequences
  • Identify conserved regions
  • Compare sequences without full alignment

Example Input

Query sequence:

ATCGATCGATCGTAGC

Database: Multiple sequences in FASTA format

Example Output

Alignment results with scores:

Hit 1: Score 85%
Query: ATCGATCG---TAGC
Match: |||||||| ||||
Subj: ATCGATCGAATAGC

FAQ

Q: How does word size affect results?
A: Smaller words find more distant matches but take longer. Larger words are faster but may miss divergent sequences.

Q: What's the difference from full alignment?
A: BLAST uses shortcuts to find likely matches quickly, while full alignment compares every position exhaustively.