Which one of the following options is a correct match between Column X and Y?
(1) A – i and iv; B – iii; C – ii and v
(2) A – ii and iv; B – iii and v
(3) A- i and iv; B – iii and v
(4) A – ii and iv; B – i and iii

Column X terms

• A. Random mutagenesis – mutations introduced at unpredictable sites across the genome.

• B. Targeted mutagenesis – precise changes at a known locus.

• C. Phenocopying – imitating a mutant phenotype without changing DNA sequence (usually transient gene knock‑down).

Column Y strategies

• i. RNAi – sequence‑specific mRNA degradation → transient loss‑of‑function phenotype.

• ii. Transposable elements – random insertion into genome causing insertional mutations.

• iii. Homologous recombination – gene targeting at a defined locus.

• iv. UV mutagenesis – random DNA damage and mutations genome‑wide.

• v. CRISPR – programmable, highly site‑specific genome editing.

Correct matches

A. Random mutagenesis → ii (Transposable elements) and iv (UV mutagenesis)

• UV light causes random point mutations and small lesions across the genome.

• Transposable elements insert more or less randomly, disrupting genes.

• Both are classic tools for random mutagenesis.

B. Targeted mutagenesis → iii (Homologous recombination) and v (CRISPR)

• Homologous recombination with a designed donor construct enables gene targeting at a specific locus.

• CRISPR–Cas systems use a guide RNA to direct cuts at defined sequences, enabling precise knockouts or edits.

• Both therefore mediate targeted mutagenesis.

C. Phenocopying → i (RNAi)

• RNA interference knocks down mRNA, creating a reversible, non‑genomic loss‑of‑function phenotype, i.e., a phenocopy of a knockout.

So the full correct pattern is:

• A – ii & iv

• B – iii & v

• C – i

which corresponds to option (1).