Final answer:
Site-specific recombination is crucial for the integration of lambdaphage DNA into the E. coli host genome during specialized transduction, allowing the transfer of specific genes and aiding in genetic diversity among bacterial populations. The correct option is B.
Step-by-step explanation:
Site-specific recombination plays a critical role in the infection of E. coli by the lambda phage. Specifically, the correct answer is B) Site-specific recombination facilitates the integration of lambdaphage DNA into the E. coli genome.
This process is known as specialized transduction and occurs at the end of the lysogenic cycle when the prophage (the viral DNA integrated into the host's genome) is excised and the bacteriophage enters the lytic cycle.
During excision, a phage may inadvertently remove some bacterial DNA near the site of viral integration. The phage and host DNA are then packaged within the capsid, which upon infecting a new host, can integrate into the host's genome alongside the phage DNA.
This integration, facilitated by site-specific recombinant enzymes, allows the bacteriophage to persist within the host as a prophage, making it possible for the phage to replicate as part of the host cell's replication cycle. This mechanism enables bacteriophages like lambda to transfer genes, such as antibiotic resistance or metabolism genes, among bacterial populations, affecting their genetic diversity.