Q.5 Program used for essentially local similarity search is
- (A) BLAST
- (B) RasMol
- (C) ExPASy
- (D) SWISS-PROT
BLAST (Basic Local Alignment Search Tool) dominates bioinformatics for detecting sequence similarities. Tailored for students in genetics and biotechnology, this article solves the MCQ on tools for local alignments, confirming (A) BLAST as the answer while clarifying all options.
What Makes BLAST Essential?
BLAST performs heuristic local alignments between query sequences (DNA/protein) and databases, identifying conserved regions without requiring global matches. Developed by Altschul et al., it seeds with short words (k-tups), extends high-scoring pairs, and reports E-values for significance—ideal for homology detection in NCBI databases.
Correct Answer: (A) BLAST
BLAST specializes in local similarity searches, finding short, biologically relevant matches like domains or motifs amid divergent sequences. Variants (BLASTN, BLASTP) support nucleotide/protein queries, powering gene annotation and phylogenetics.Explanation of All Options
Each option’s role in bioinformatics:
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(A) BLAST
Correct. Designed explicitly for local alignments via Smith-Waterman-like extensions, unlike global tools (e.g., Needleman-Wunsch). Essential for database searches in genomics. -
(B) RasMol
Incorrect. RasMol visualizes 3D protein structures from PDB files (e.g., ribbons, surfaces)—no sequence search capability. -
(C) ExPASy
Incorrect. ExPASy is a portal aggregating tools (e.g., ProtParam, Swiss-Model) for protein analysis—not a standalone search program. -
(D) SWISS-PROT
Incorrect. SWISS-PROT (now UniProtKB/Swiss-Prot) is a curated protein sequence database, not a search tool.
Option Primary Function Local Search? Bioinformatics Use (A) BLAST Sequence alignment Yes Homology detection (B) RasMol 3D structure viewing No Molecular visualization (C) ExPASy Analysis portal No Protein tools suite (D) SWISS-PROT Protein database No Sequence repository Applications for Biotech Students
Use BLAST for sequence alignment in cloning validation or primer design; integrate with tools like CLUSTAL for multiples. Its speed suits large datasets in molecular biology workflows.
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