BLAST analysis

BLAST uses statistics to sort the sequence database and thus, identify the best matches.

Figure 1: Color-coded alignment score.

The user receives the following output:

• Max score

• Total Score

• Query Coverage

• E-value

• Maximum Identity

The E-value or expected value represents the number of hits you expect to find in a database of the same size. Low E-values indicate a significant result. The Maximum Identity represents the percentage of the shared identities between the query and the hit in a nucleotide-to-nucleotide alignment. The alignment scores are numerical values that describe the overall quality of an alignment. The percentage of the query length that is included in the aligned segments is called the query coverage.

Figure 2: Blast result.