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Algorithmic Thinking in Bioinformatics · Quiz 2 · 3 Aug 2025 · May 2025 term

Question 1: Given below are three algorithms for the motif finding pr…

Question 1

+5 marksOne correct option

Given below are three algorithms for the motif finding problem. Identify which figure belongs to which algorithm.

text
████████
randomly select k-mers Motifs = (Motif_1, ..., Motif_t) in each string from Dna
BestMotifs ← Motifs
for j ← 1 to N
i ← RANDOM(t)
Profile ← profile matrix formed from all strings in Motifs except for Motif_i
Motif_i ← Profile-randomly generated k-mer in the i-th sequence
if SCORE(Motifs) < SCORE(BestMotifs)
BestMotifs ← Motifs
return BestMotifs

(a) Figure I

text
████████
BestMotifs ← motif matrix formed by first k-mers in each string from Dna
for each k-mer Motif in the first string from Dna
Motif_1 ← Motif
for i = 2 to t
form Profile from motifs Motif_1, ..., Motif_{i-1}
Motif_i ← Profile-most probable k-mer in the i-th string in Dna
Motifs ← (Motif_1, ..., Motif_t)
if SCORE(Motifs) < SCORE(BestMotifs)
BestMotifs ← Motifs
return BestMotifs

(b) Figure II

text
████████
randomly select k-mers Motifs = (Motif_1, ..., Motif_t) in each string from Dna
BestMotifs ← Motifs
while forever
Profile ← PROFILE(Motifs)
Motifs ← MOTIFS(Profile, Dna)
if SCORE(Motifs) < SCORE(BestMotifs)
BestMotifs ← Motifs
else
return BestMotifs

(c) Figure III

  1. A

    Figure I: Gibbs Sampling; Figure II: Randomized Motif Search; Figure III: Greedy Motif Search

  2. B

    Figure I: Gibbs Sampling; Figure II: Greedy Motif Search; Figure III: Randomized Motif Search

  3. C

    Figure I: Greedy Motif Search; Figure II: Randomized Motif Search; Figure III: Gibbs Sampling

  4. D

    Figure I: Randomized Motif Search; Figure II: Gibbs Sampling; Figure III: Greedy Motif Search

Show answer

Correct answer

  • B

    Figure I: Gibbs Sampling; Figure II: Greedy Motif Search; Figure III: Randomized Motif Search

Question 1 of 18 in the IIT Madras BS Algorithmic Thinking in Bioinformatics (Algorithmic Thinking in Bioinformatics) Quiz 2 paper sat on 3 Aug 2025, in the May 2025 term (IIT M IMPROVEMENT AN EXAM QIA2 03 Aug 2025). It carries 5 marks.

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