Genetic Engineering

Genetic engineering is the direct human manipulation of an organism's genome using modern DNA technology. It involves the introduction of foreign DNA into the organism of interest. DNA that contains genetic material from another organism is referred to as Recombinant DNA.

An organism that is generated through the introduction of recombinant DNA is considered to be a genetically modified organism (GMO). The first organisms genetically engineered were bacteria in 1973 and then mice in 1974. Insulin-producing bacteria were commercialized in 1982 and genetically modified food has been sold since 1994.

The most common form of genetic engineering involves the insertion of new genetic material into the host genome. This is accomplished by isolating and copying the gene of interest using molecular cloning methods and then inserting the gene into the host organism. Since this technique was first used to modify bacteria to produce human insulin, that is the example that we will use to understand the process.

X = Restriction Enzyme Y = DNA Ligase

Step 1: Choose a genetic trait (human insulin) to splice into the DNA of the Host Organism

Step 2: Choose a Host Organism (bacteria)

Step 3: Cut out the gene that codes for the genetic trait that you want to transfer into the host organism. You must choose a restriction enzyme that cuts out the gene with cutting off part of it. The enzyme should also leave sticky ends (with dangling bases that can pair with dangling bases on the host organism's DNA).

Step 4: Obtain a plasmid from a bacterium.

Step 5: Cut open the plasmid using the same restriction enzyme that you chose to cut out the gene of interest. This will create complementary sticky ends that will match up like puzzle pieces with the sticky ends on the gene.

Step 6: Combine the gene that you removed and the plasmid that you cut open. The sticky ends will match up and the gene will join with the plasmid. The gene must be "glued" into the plasmid with another enzyme called DNA Ligase.

Step 7: Mix the recombinant DNA with bacteria cells and they will suck up the newly engineered plasmid. This will give the bacteria the ability to read the new gene and produce the protein (insulin in this case). Also, the bacteria will clone themselves and all the new bacteria will also contain the new gene and will be able to produce the protein.

Step 8: Feed the bacteria. It will continue to reproduce asexually and produce the protein of interest. After some time, remove the protein from the bacteria and purify it for use.

X = cloned bacteria that contain newly inserted gene and can produce inslulin