sci.sequence-identity Calculator
Calculates percent sequence identity from pairwise sequence alignment: PID = (identical positions/aligned length) × 100%, and similarity with conservative substitutions. Proteins with PID > 30% are likely structurally homologous; PID < 20% requires caution in structure prediction — the 'twilight zone' is 20–30% PID.
Inputs
- Aligned Length
- Linear measurement. Ensure consistent units: 1 m = 1,000 mm = 3.281 ft.
- Identical Positions
- Reference formula or conversion factor shown for context.
- Gap Positions
- Reference formula or conversion factor shown for context.
Results
- sequence identity (%)
- Sample size or count used in the calculation.
- identity (gap-excluded)
- Sample size or count used in the calculation.
- gaps (%)
- Reference formula or conversion factor shown for context.
- E-value threshold
- The computed numeric or monetary value.
- identity interpretation
- Qualitative summary of what the computed numbers mean in practical terms.
- structural similarity
- Reference formula or conversion factor shown for context.
identical sequence alignment positions excluded