Specialized transduction specifics Specialized (restricted) transduction by bacteriophages occurs under which genomic integration condition?

Introduction / Context:Transduction transfers bacterial genes via phages. Specialized transduction is limited to genes adjacent to a prophage that integrates at a specific chromosomal site (e.g., lambda at attB in E. coli).

Given Data / Assumptions:

• Lysogenic cycle involves site-specific integration.
• Excision errors can co-mobilize neighboring host DNA.
• Resulting phage carries restricted sets of host genes.

Concept / Approach:Because integration is site-specific, only genes near the attachment site are transduced upon imprecise excision, defining “specialized” transduction. In contrast, generalized transduction arises from random packaging.

Step-by-Step Solution:Site-specific integration at att site.Abnormal excision captures adjacent host DNA.Packaging yields transducing particles with restricted gene content.

Verification / Alternative check:Mapping of transduced markers shows tight linkage to integration sites, unlike generalized transduction.

Why Other Options Are Wrong:Random integration (option a) describes transposons; “never integrates” (option b) contradicts lysogeny; immediate lysis (option e) describes lytic cycle, not specialized transduction.

Common Pitfalls:Confusing specialized with generalized transduction; overlooking the role of site-specific recombinases.

Final Answer:The bacteriophage always incorporates at the same position in the bacterial chromosome.