By Sarah Sui
Recombinant DNA (shortened as rDNA) technology was created in the 1970’s. Spearheaded by biochemists Paul Berg. Since then it has become a large part of our daily lives. It is essential in pharmaceuticals and medicine, and can even be seen in the agricultural industry.
What is Recombinant DNA?
Recombinant DNA is DNA that is artificially formed by combining fragments (constituents/components) from different organisms. It is essentially taking a piece of DNA and combining with another strand. This process involves two main figures: enzymes and vectors. For enzymes, the most important ones are restriction enzymes and DNA ligase. Restriction enzymes locate and recognize a target sequence. They cut DNA at or near that site and produces cuts with short, single-stranded overhang. This is done to the DNA of both organisms. The result is a target gene fragment and it’s vector. Vectors are small replicating molecules (carriers). The most commonly used vectors are plasmids. Which are circular DNA molecules originating in viruses, bacteria and yeast cells. If the overhang of the two molecules match. They can base-pair and stick together. Following that, DNA ligase will come in and seal the gap. The product is rDNA.
First Recombinant DNA molecule
In late 1971, at Paul Berg’s laboratory in Stanford, the first recombinant molecule containing DNA from different organisms was created. It began with Berg wondering whether it was possible to insert foreign genes into a virus. So he took the restriction enzyme called ECoRI, and used it to cut a fragment of DNA from the bacterial virus known as lambda. He then inserted that into the DNA of the simian virus SV40, which in this case, would be the vector. The enzyme cut both DNA molecules at the same place to create complementary sequences. Which is basically to ensure they have matching base pairs. Using a variety of other enzymes, Berg joined the fragment and the vector. Creating the first rDNA molecule.
Public Fears
Berg was ready to move onto the next step of inserting this rDNA into bacteria. But he didn’t get to, because this new technology had sparked public controversy over the potential hazards of inserting rDNA into another organism. People were in fear that the recombinant DNA would carry a bad gene such as one for cancerous tumors, and that it might escape the labs through a common bacterium. Berg was the chair of the National Academy of Science’s Committee on Recombinant DNA Molecules. As chair, he led rDNA researchers to address public concerns and debate the physical and ethical precautions regarding this new technology. Such debate came to success in the mid 1970’s when the National Institutes of Health issued guidelines for rDNA research. With time and more experience on this subject, these guidelines have been loosened.
Recognition
Nonetheless, even without taking this next step, Berg had contributed greatly to the science community. In 1980, he received ½ of the Nobel Prize Award in Chemistry “for his fundamental studies of the biochemistry of nucleic acids, with particular regard to recombinant-DNA.”
Recombinant Technology in Vaccines & Insulin Production
1986 marked the creation of a safer, more easily produced Hepatitis B vaccine. This recombinant vaccine replaced the original blood plasma derived vaccine. It is made by taking the section of the HBV gene that codes for it’s surface antigen (HBsAG) and inserting that into yeast (Saccharomyces cerevisiae) DNA. This recombinant yeast cell will then multiply and produce the HBV antigen in fermentation tanks. The collected antigen is purified and treated before taking form in the vaccine. When the vaccine is given, our bodies will make an immune response to the surface antigen and protect us against infection. Human insulin for diabetes is produced in a similar manner.
The Widespread Impact of rDNA
Many of my relatives have diabetes and rely on insulin. So I am incredibly grateful for scientists’ work on this astounding technology. Most people don’t realize it, but recombinant DNA has actually become a huge part of our lives. Even if you aren’t affected by a medical condition (i.e. HBV, diabetes) that may require recombinant pharmaceuticals. You’re still constantly exposed to them. Take GMOs as an example. Everyone knows what they are, as they can be seen in grocery markets all over the world. But did you know that one of the techniques for developing GMOs is recombinant DNA technology? Recombinant DNA is wonderful. I has helped (or has at least positively impacted) the lives of billions of people.
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