Back in the day, diabetics who needed insulin to survive were injected with cow or pigeon insulin, which was not ideal for the human body. Now the insulin injected into the patients is human. This insulin is produced by microorganisms such as E cole, bacteria and yeast. How can microorganisms produce human insulin? This is due to Genetic Engineering. Genetic Engineering enables scientists to convert microorganisms into factories that can create useful substances.
An organism’s DNA makes up its gene which is the code for all proteins that organisms need to survive. Each gene encodes a different protein. Genetic Engineering is the manipulation of the DNA of an organism. It involves removing a gene from one organism and transferring it into another. The one that gives is the donor and the one that receives is the recipient, who is also known as the genetically modified organism.
Scientists use Genetic Engineering to produce large volumes of proteins, like growth hormones, insulin and vaccines. An organism B can contain another gene, but on introducing a different gene from A, B gets genetically modified. For example, a gene manufacturing toxic chemicals with bacteria can be introduced to a plant to make it toxic so that insects do not eat it.
Let us now look at the process of Genetic Engineering and how to transfer genetic characteristics from one organism to another. Although it is a very complex process, it can be summarized. We’ll use the example of how an insulin gene is inserted into a bacterium to manufacture large amounts of human insulin.
The gene that encodes human insulin is found on chromosome 11 at position 15.5. The insulin gene is cut from chromosome 11 using a special enzyme called the restriction enzyme. Bacteria possess a small circular strand in the cytoplasm called a plasmid. It is extracted from the cell and is cut open using the same restriction enzymes. These enzymes leave sticky ends where one end is longer than the other. Since the same enzyme was used to cut both, the sticky ends are called complementary and will allow for the joining of the complementary base pairing. The insulin gene is joined to the plastid by the sticky ends. The enzyme called ligase is used to complete the joining of the two. The modified plastid is again reinserted into the bacterium cell. The new bacteria is a genetically modified organism as it contains some human DNA along with its own bacterial DNA. This cell is then placed in a fermenter which allows rapid asexual reproduction. As the bacteria reproduce asexually, the offspring will have identical DNA. The bacteria express their own genes in order to divide. They make their own bacterial proteins but also express the human insulin gene and produce insulin. They become the many factories producing human insulin. Insulin is then extracted, purified and carefully packaged. Diabetics can now inject themselves with human insulin. That is how Genetic Engineering works.
Bibliography:
n.a. “ Genetic Engineering” YouTube. 16th Nov, 2020. Video. 18th Dec, 2022. <https://youtu.be/DIM38NlkWEo >
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