DNA transfer in bacteria via phage is:

Ref: Textbook of Microbiology by Surinder Kumar, P 93 Microbiology by Ananthanarayan and Paniker, 8th ed., pg. 60Some bacteria also transfer genetic material between cells via following ways:* Transduction: Transfer of genetic material from one bacterium to another by a bacteriophage is known as transduction# Most widespread mechanism of gene transfer among prokaryotes* Transformation: Transfer of genetic material through the agency of free DNA* Conjugation: DNA is transferred through direct cell contact. Gram negative anerobes like E. Coli, Bacteroides, Porphyromonas, and Fusobacterium use this method of gene transfer* Bacteriophages are viruses that parasitize bacteria* Most bacteriophages carry their genetic information (the phage genome) as a length of double-stranded DNA coiled up inside a protein coat.* Lysogenic conversion: Phage DNA integrated in bacterial chromosome as prophase - replicated stably as part of host cell chromosome - transferred to daughter cell.# In other words: "This process by which the prophage DNA confers genetic information to a bacterium is called lysogenic or phage conversion."# NOTE: In transduction, phage acts only as a vehicle carrying bacterial genes from one cell to another but in lysogenic conversion the phage DNA itself is the new genetic element.