Do the BLAST scores have any relation between them?
2
0
Entering edit mode
6.0 years ago
Bahrani ▴ 30

Is there any relation among the BLAST scores (E-value, similarity, identity, gap, bit score)?  Is the e-value score for an alignment proportional to other scores, such as similarity score (i.e. the lower the e-value, the higher the similarity)?

Thank you!

BLAST alignment score e-value sequence • 1.8k views
2
Entering edit mode
6.0 years ago

The e-value is calculated by taking the score and including the number of sequences in your database, i.e., "what is the probability that I get this score with this many sequences?"

See previous discussions, E-Value In Blast or Blast E Value Calculation

The score depends on the length of your alignment and your chosen substitution matrix, see these slides

0
Entering edit mode
6.0 years ago

Yes they do.

https://en.wikipedia.org/wiki/BLAST