Transduction is the process by which DNA is transferred between bacteria via a virus. It involves a bacteriophage infecting a bacterial cell and using the cell's machinery to produce new virus particles, which may incorporate small fragments of bacterial DNA into new viral genomes. This allows genetic material to be transferred from one bacterium to another without direct contact when the new viruses infect other bacteria. Transduction differs from transformation in that the transferred DNA is protected from DNase inside the viral particle. It is a molecular biology tool for introducing foreign DNA into host genomes.