Given below are terms related to various techniques (Column X) and their features (Column Y):

Column X Techniques		Column Y Features
A.	Reverse transcription	I.	Detection of clones encoding nucleic acid binding proteins
B.	Southwestern blotting	II.	Determination of 5’ and 3’ DNA sequences flanking a known gene
C.	Genome walking PCR	III.	Cloning of cDNA ends
D.	RACE	IV.	cDNA library

​Which one of the following options represents all correct matches between Column X and Column Y?​

Correct option is A

A. Reverse Transcription → iv. cDNA library

• Reverse transcription is the process of converting mRNA into cDNA using the enzyme reverse transcriptase.
• This is the first step in generating cDNA libraries, where the cDNA represents the expressed genes of a cell/tissue.
• Correct Match: A → iv

B. Southwestern Blotting → i. Detection of clones encoding nucleic acid binding proteins

• Southwestern blotting is used to detect DNA-binding proteins by probing protein blots with labeled DNA sequences.
• Useful in identifying transcription factors or other DNA-binding proteins.
• Correct Match: B → i

C. Genome Walking PCR → ii. Determination of 5’ and 3’ DNA sequences flanking a known gene

• Genome walking is used to identify unknown DNA sequences adjacent to a known region, often used to explore promoter or downstream regions.
• Correct Match: C → ii

D. RACE (Rapid Amplification of cDNA Ends) → iii. Cloning of cDNA ends

• RACE PCR is specifically designed to amplify the 5′ and 3′ ends of cDNA. It is commonly used for obtaining full-length cDNA clones.
• Correct Match: D → iii

Information Booster:

1. Reverse Transcription (RT) is essential in RNA expression analysis, such as RT-PCR and microarray-based transcriptomics.
2. Southwestern Blotting is a hybrid technique of Southern and Western blotting to detect nucleic acid-protein interactions.
3. Genome Walking PCR enables researchers to walk into unknown DNA regions, helpful in gene discovery and flanking sequence analysis.
4. RACE-PCR is widely used for obtaining full-length cDNA, particularly for eukaryotic gene cloning where mRNA ends are essential.
5. These techniques collectively contribute to gene identification, regulation studies, and molecular diagnostics.
6. Use of specific probes and primers in each method ensures high specificity and functional resolution.
7. Understanding technique-feature correlation helps in selecting the right molecular tool for genetic research.

Additional Information on Incorrect Options:

• Option 2 (A-iii, B-iv, C-i, D-ii): Incorrect. A-iii and B-iv are mismatched. Reverse transcription does not directly deal with cDNA ends.
• Option 3 (A-ii, B-iii, C-iv, D-i): Incorrect. Reverse transcription is not for flanking sequence detection (A-ii is wrong); C-iv is also incorrect.
• Option 4 (A-iv, B-i, C-iii, D-ii): Almost correct except C-iii is incorrect; genome walking is for flanking sequences, not cDNA ends.