BLAST Percent Identity Calculator

Formula

The formula to calculate the BLAST Percent Identity (BI) is:

\[ \text{BI} = \left(\frac{\text{M}}{\text{L}}\right) \times 100 \]

Where:

\( \text{BI} \) is the percent identity
\( \text{M} \) is the number of identical matches
\( \text{L} \) is the total alignment length

What is BLAST Percent Identity?

BLAST Percent Identity is a measure used in bioinformatics to quantify the similarity between two sequences. It represents the percentage of identical matches between the query sequence and the subject sequence over the total length of the alignment. This metric is crucial for understanding the degree of similarity and potential functional or evolutionary relationships between sequences. A higher percent identity indicates a greater similarity between the sequences.

Example Calculation

Let's assume the following values:

Number of Identical Matches (M) = 80
Total Alignment Length (L) = 100

Using the formula to calculate the BLAST Percent Identity:

\[ \text{BI} = \left(\frac{80}{100}\right) \times 100 = 80\% \]

The BLAST Percent Identity is 80%.