With respect to gene transfer and the integration of the transferred gene into the recipient genome: -
a. The host genes are transferred in a linear fashion from high-frequency recombination cell (Hfr cell) through conjugation. The genes transferred depend on both the Hfr strain and the length of time during which the transfer occurred. Therefore, a population containing several different Hfr strains will appear to have an almost random transfer of host genes. This is similar to generalized transduction, in which the viral protein coat forms around a specific amount of deoxyribonucleotide (DNA) rather than specific genes. Any gene can be transferred in generalized transduction
b. Improper excision of Hfr from the bacterial chromosome gives rise to F′ factor. The integration site is fixed for each strain hence they have only specific bacterial genes on them. Specialized transduction resembles F′ derivatives, in that the viral particle integrates into a specific region of the bacterial chromosome and then, upon improper excision, can take with it only specific bacterial genes. The transferred gene exists as a second copy in both cases.