Vectors are a tools used by molecular biologists to deliver genetic material into cells. This process will performed inside the cells culture and viruses have the special molecular mechanisms to transport the genome inside the cells they infect. Delivery of any genes or genetic material is termed as transduction and it is infected the cells. Paul Berg used a modified SV40 virus containing DNA which infected the monkey kidney cells maintained in the culture.
Sometimes viral vectors are occasionally created pathogenic viruses because they are formed to minimize the risk of handling them. It usually involves the deletion of a part of viral genome and some virus infect the cells but it reuires the helper virus to provide the missing proteins. The Viral Vectors were developed with a DNA for molecular genetics experiments.