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Exploring Evolutionary Relationships Using BLAST

This workshop will be held virtually on August 3, 2023.

Workshop Duration:  2 hours

Content Difficulty:  Beginner

Target Audience: Life scientists, including research students and educators, who wants to use BLAST in their project or workflow.  Familiarity with genetics and evolutionary biology vocabulary and concepts is recommended

Workshop Description: 
Identification of evolutionarily related DNA or protein sequences (homologs) is a crucial step in many biology workflows. For example, homologous sequences are used to infer relationships between organisms, understand how sequence changes affect observable traits, and identify potential animal models for genetic disorders.  

NCBI’s BLAST program is a standard tool for identifying homologs, and this virtual workshop will teach you best practices for using it for your analysis goals. You will learn when and how to use important but often misunderstood aspects of the BLAST programs and databases, such as when it’s helpful to change the BLAST program by using filters and adjusting parameters such as word size, e-value cutoff, and maximum target sequences.

In this workshop, you will use web-based NCBI resources to: 

  • Select the correct NCBI alignment tool and BLAST database for your search goal 
  • Use other NCBI sequence analysis services including COBALT, a multiple protein sequence alignment tool 
  • Make use of the new organism-based nucleotide and ClusteredNR protein databases to easily assess the taxonomic diversity of your BLAST results 
  • Visually examine results using auxiliary tools such as TreeViewer, Multiple Sequence Alignment, Graphical Sequence, and the Genome Data viewers.  


Data Access Technology:  NCBI website

NCBI Resources:  BLAST, COBALT, ClusteredNR database, TreeViewer, Sequence Viewer

Last Reviewed: July 29, 2023