Which Cell to Engineer

Cloning a gene means making copies of the same DNA sequence. As described above, this can be done with PCR. Another way scientists clone DNA is to insert it into a plasmid with RE, use the plasmid to transform a bacterial culture, grow a large number of modified bacteria, extract the DNA, and then clip it back out with the appropriate RE. 

For most uses, and particularly for use as a drug, a protein must be consistent, so that every molecule in the botde is just like every other molecule. An important method used to increase the odds that every protein in the botde is identical is to make sure that the cells producing the protein— whether bacteria, animal, or human—are identical with the gene cassette in the same place in the cell s genetic material. 

The process of producing a culture of identical cells descended from a single common ancestor is also called cloning. Whether the cells are bacterial, yeast, plant, animal, or human, the principle of creating a culture of genetically identical cells is the same First, scientists need the mixture of the cells with a known concentration and a litde plastic tray with a set of small wells, each able to hold about 1/100 of a liter. Then, the scientists will  

Every cell in each resulting individual culture will be genetically identical, though the cultures may be different from each other. Then the scientists test a sample from each well to see which ones 

---