Q.No. 54 An algorithm was designed to find globins in protein sequence databases.
A database which has 78 globin sequences was searched using this algorithm.
The algorithm retrieved 72 sequences of which only 65 were globins.
The sensitivity of this algorithm is _____________ % (round off to 2 decimal places).
Sensitivity measures the algorithm’s ability to correctly identify true globins from the database. Here, true positives (TP) are 65 (correctly retrieved globins), and total actual globins are 78, so sensitivity is (65/78) × 100 = 83.33%.
Sensitivity Calculation
Sensitivity, also called true positive rate (TPR) or recall, uses the formula:
TP = 65 (globins correctly retrieved).
FN = 78 – 65 = 13 (globins missed).
Thus, (65 / 78) = 0.8333…, and 0.8333 × 100 = 83.33% (rounded to two decimal places).
Confusion Matrix Breakdown
From the data:
- Total actual globins (positives) = 78
- Retrieved sequences = 72 (TP + FP = 72, where FP = 72 – 65 = 7 false positives)
- Non-globins in database are irrelevant for sensitivity, as it focuses only on detecting true positives among actual positives
No options are provided in the query, but common distractors include confusing sensitivity with precision (65/72 ≈ 90.28%) or accuracy.
Introduction to Globin Sequence Algorithm Sensitivity
In bioinformatics, globin sequence algorithm sensitivity evaluates how well tools detect true globins in protein databases, vital for exams like GATE Biotechnology. This GATE 2020 question (Q.No. 54) tests confusion matrix basics: a database with 78 globins yields 72 retrieved sequences, 65 true positives. Sensitivity formula delivers 83.33%, rounding to two decimals.
Step-by-Step Sensitivity Formula Derivation
Apply formula: Sensitivity = TP/(TP+FN) × 100 = 65/78 × 100
Compute: 65 ÷ 78 = 0.833333…; ×100=83.3333…%; round to 83.33%.
False positives (7) affect precision, not sensitivity.
Common Errors in Globin Algorithm Analysis
- Mistaking for precision: 65/72 × 100 ≈ 90.28%
- Including non-globins: Irrelevant, as sensitivity ignores true negatives
- No rounding: 83.333… must be 83.33%. Perfect for IIT JAM/GATE biotech prep
Bioinformatics Context for Exam Success
Globin sequence algorithm sensitivity shines in database searches like BLAST for hemoglobin/myoglobin families. High sensitivity (83.33%) means low false negatives, key for genomic research. Practice similar PYQs to ace competitive biotech exams.
