Transfection

Transfection is the name used when we add naked DNA to cultured cells. The naked DNA is placed in the medium where the cells are being cultured. About 1 cell in every 10⁵ to 10⁶ takes up the DNA and incorporates it into its genome. If the naked DNA includes a marker sequence, such as a gene for pesticide resistance, we can easily identify the cells with the incorporated DNA by growing them with an antibiotic. There are other ways to transfect cells. The naked DNA can be injected into the nucleus of the cell. This method is easiest if the host cell is large in size such as an oocyte. Another way to transfect is to use electroporation. In this situation, the medium contains electrodes that give brief shocks. The shocks make the cell membrane transiently permeable. The bottom line is that the DNA from one organism is placed into another organism. This organism is now called a transgenic organism.