Typical sexual reproduction is absent in bacteria because of absence of meiosis and gamete formation. Instead, gene recombination occurs parasexually by three methods-conjugation, transformation and transduction.
During conjugation the male ($F^+$) or donor transfers its $F^+$ plasmid to female $(F^-)$ cell through conjugation tube (protoplasmic bridge established by pilus of male cell). Transformation is the absorption of DNA segment from
surrounding medium by a living bacterium. Transduction involves transfer of foreign gene by bacteriophages (virus infecting bacteria) wherein virus may pick up a gene of host in place of its own gene during its multiplication in the host cell and pass it to new host while infecting it.