Vídeo de DNA uptake by a cell, animation.

The insertion of new strands of DNA into a cell is a common feature of genetic engineering. If the DNA is from a different organism, it is called transgenics. Circular loops of DNA such as this are called plasmids. One popular use of the technique is the insertion of a gene for a particular protein into a bacterial cell, which is then expressed, causing the bacteria to produce a useful protein, such as insulin