Molecular Systematics of Nematodes - Russian Journal of Nematology

Blast (Sequence Similarity Search)
The graphic display
• Your query sequence in on the top
• Each bar represents the portion of another
sequence similar to your query sequence
• Red bars indicate the most similar sequences,
pink bars indicate matches that are a bit less
good, and green bars indicate matches that
are not impressive at all. Blue and black hits
(not here) are bad hits
The hit list
Each line contains four important features:
• The sequence accession number and the
names: this hyperlink takes you to the
database entry that contains this sequence
• Description
• The bit score: a measure of the statistical
significance of the alignment. The higher the
bit score, the more similar the two sequences.
Matches below 50 bits are very unreliable
• The E-value (the expectation value): by
estimating the number of times you could
have expected such a good much only by
chance. The lower the E-value, the more
similar the sequences. If the E-value is less
than 1 X 10 -50 ,the hit is very similar to the
query sequence and is very likely to be
evolutionarily related.