This tutorial demonstrates how use Nucleotide BLAST to align and compare two or more DNA sequences. To initiate an alignment, in this demonstration, a reference DNA sequence is entered into the query box and compared to additional DNA sequences that are entered into the subject box. Using the descriptions tab within the alignment results, it is possible to get an idea of the coverage as well as the percent identity between each subject alignment with the query. Assessing the alignments using pairwise with dots for identities allows for a quick visualization of differences between two sequences including single base substitutions as well as deletions and insertions.
Nucleotide BLAST: blast.ncbi.nlm.nih.gov/Blast....
Genomic Education at The Jackson Laboratory: www.jax.org/education-and-lea...
BLAST Tutorial Series Playlist: • BLAST Tutorial Series
Key moments:
0:00 Introduction
0:38 Navigating to Nucleotide BLAST (BLASTn)
0:57 Comparing two or more DNA sequences
1:28 What is a reference sequence?
1:36 Entering a Query sequence
2:10 Entering Subject sequences
3:03 BLAST results page navigation
3:33 What is coverage?
4:01 What is percent identity?
4:41 Visualizing sequence alignments
Keywords: BLAST, Nucleotide BLAST, DNA sequence comparison, gene variants