Molecular Biology and Biotechnology- ICAR JRF/SRF 2024

• Molecular Blotting Techniques: Blotting techniques transfer separated biomolecules from an electrophoresis gel onto a solid membrane (nitrocellulose or nylon) for specific hybridization detection:
• Pair-by-Pair Matching:
• Southern Blot $\rightarrow$ (II) DNA: Developed by Edward Southern (1975) to detect specific DNA sequences using DNA/RNA probes.
• Western Blot $\rightarrow$ (III) Protein: Uses specific antibodies to detect target proteins after SDS-PAGE separation.
• Northern Blot $\rightarrow$ (IV) RNA: Detects specific RNA transcripts (gene expression) using labeled probes.
• Far Western Blot $\rightarrow$ (I) Protein-protein: Detects protein-protein interactions by probing membrane-bound proteins with non-antibody bait proteins.
• Correct Choice: Option 3 represents the accurate mapping: (A)-(II), (B)-(III), (C)-(IV), (D)-(I).

Correct option: (3) (A) - (II), (B) - (Il), (C) - (IV), (DB) - (1)

• Sequencing by Ligation (SBL): The SOLiD (Sequencing by Oligonucleotide Ligation and Detection) platform, developed by Applied Biosystems/Life Technologies, utilizes DNA ligase rather than DNA polymerase to determine target sequences using fluorescently labeled 8-mer probes interrogating two-base encodings.
• Comparison with Other Platforms:
• Nanopore technology: Measures changes in electrical ionic current as single-stranded DNA passes through a biological protein nanopore (sequencing by electrical current modulation).
• DNA nanoball (DNBSEQ/BGI): Uses rolling circle amplification and combinatorial probe-anchor synthesis (cPAS).
• HeliScope: Single-molecule sequencing-by-synthesis (SBS) using fluorescent dNTPs and DNA polymerase.
• Conclusion: SOLiD technology uniquely relies on sequencing by ligation (Option 1).

Correct option: (1) SOLID technology

• Quantitative Estimation of Proteins: ELISA (Enzyme-Linked Immunosorbent Assay), especially sandwich ELISA, is a widely used quantitative antibody-based assay to determine the concentration of specific proteins/antigens in biological samples using an enzyme-substrate chromogenic readout and a standard curve.
• Other Listed Techniques:
• Real-Time PCR (qPCR): Used for quantitative estimation of nucleic acids (DNA/cDNA).
• ddPCR (Droplet Digital PCR): Used for absolute quantification of nucleic acid target copy numbers.
• Reverse Transcriptase PCR (RT-PCR): Qualitative or semi-quantitative amplification of RNA molecules.
• Conclusion: ELISA is specifically designed for protein quantification (Option 3).

Correct option: (3) ELISA