UNIT 3.4 Finding Homologs in Amino Acid Sequences Using Network BLAST Searches

  1. Istvan Ladunga

Published Online: 1 FEB 2003

DOI: 10.1002/0471250953.bi0304s00

Current Protocols in Bioinformatics

Current Protocols in Bioinformatics

How to Cite

Ladunga, I. 2003. Finding Homologs in Amino Acid Sequences Using Network BLAST Searches. Current Protocols in Bioinformatics. 00:3.4:3.4.1–3.4.33.

Author Information

  1. Celera Genomics, Foster City, California and Research Group for Evolutionary Genetics Hungarian Academy of Sciences Eötvös University, Budapest, Hungary

Publication History

  1. Published Online: 1 FEB 2003
  2. Published Print: JAN 2003

This is not the most recent version of the article. View current version (1 MAR 2009)


BLAST, Basic Local Alignment Search Tool is used more frequently than any other biosequence database search program. The purpose of this unit is not only to show how to run searches on the Web, but also to demonstrate how to fine-tune arguments for a specific research project. It also offers guidance for interpreting results, handling statistical significance and biological relevance issues, and selecting complementary analyses. This unit covers three classes of the BLAST program: standard protein-to-protein searches, translated searches when either the query or the database consists of nucleotide sequences translated into proteins, and finally programs for comparing two sequences (as opposed to searching one sequence against a database of sequences).