A bacteriophage lambda genome integrates into the E. coli chromosome and remains dormant as a prophage. When it excises imprecisely, it carries adjacent bacterial genes to the next host cell. This mode of gene transfer is best described as:
- A Generalized transduction
- B Lysogenic conversion
- C Specialized transduction ✓
- D Site-specific recombination
Correct answer: C. Specialized transduction
Explanation
Specialized (restricted) transduction occurs when an integrated prophage excises aberrantly and takes with it only the bacterial genes immediately adjacent to the attachment site, such as gal or bio in lambda. Generalized transduction involves random packaging of any bacterial DNA by a lytic phage. Lysogenic conversion transfers only phage-encoded traits such as diphtheria toxin, not adjacent chromosomal genes.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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