Genetic engineering involves the splicing of genes, essentially recombining genetic information like the cutting and pasting of text on your computer. Genes from different organisms can be incorporated together, for example allowing livestock to produce human hormones. This is known as recombinant dna. But how do we incorporate these gene splicings into the cells of the host animal? Well it turns out that viruses which are snippets of rna code have this ability, it is how they take over the operations of the cells and turn the mechanisms of the cell into virus manufacturing centers. Of particular interest to geneticists are a class of viruses known as retroviruses which are modified by genetic scientists so they incorporate the genetic information the geneticists want to implant using the transcription mechanisms inherent in the virus.
i stil don't get it why virus? why we don't just use bacteria?