Practice question

Generalized transduction results from packaging error during lytic assembly of temperate or virulent phage such as P1 or P22. Phage terminase occasionally recognizes pseudo-pac site on host chromosome and fills capsid with random host fragment of size limited by head capacity, about 100 kb for P1. Any bacterial gene can be packaged with roughly equal probability, so lysate contains mixture covering entire genome. Transducing particles infect new cells but inject only bacterial DNA, which recombines. This randomness allows mapping any gene and building linkage clusters via co-transduction analysis.