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Genetic engineering

life science Maturity 9-11 Next article →

Genetic engineering is a set of technologies used to change the genetic makeup of cells. Scientists use these tools to modify, manipulate, or even remove an organism's genes. This process can involve transferring genes within a single species or across different species boundaries. The goal is often to produce improved or novel organisms with specific traits. This is very different from traditional breeding. In traditional breeding, people perform many crosses to select for a desired phenotype, or physical trait. Genetic engineering is much faster because it takes a specific gene directly from one organism and delivers it to another.

Breeding transgenesis cisgenesis
Breeding transgenesis cisgenesis

To begin the process, scientists must obtain new DNA. They do this by isolating and copying genetic material using recombinant DNA methods. They can also use artificial synthesis to create DNA from scratch. Once the DNA is ready, it is often organized into a construct. This construct is then used to insert the new material into a host organism. Scientists may use a vector system to carry the DNA inside. Other methods include micro-injection, macro-injection, or micro-encapsulation. In some cases, a gene gun is used to shoot DNA into cells.

Genegun
Genegun

There are several ways to classify the resulting organisms. An organism created this way is a genetically modified organism, or GMO. If the new DNA comes from a different species, the organism is called transgenic. If the DNA comes from the same species or one that can naturally breed with the host, it is called cisgenic.

Agrobacterium-tumefaciens
Agrobacterium-tumefaciens

Scientists can also use these tools to remove genes. This process is known as a "knockout," and the resulting entity is a knockout organism.

PCWmice1
PCWmice1

These different methods allow for precise control over the genetic structure of the host.

The history of this field began in the early 1970s. In 1972, Paul Berg designed the first recombinant DNA molecule. He combined DNA from the monkey virus SV40 with the lambda virus. In 1973, Herbert Boyer and Stanley Cohen created the first transgenic organism. They inserted antibiotic resistance genes into the plasmid of an Escherichia coli bacterium. In 1974, Rudolf Jaenisch created the first GM animal by inserting foreign DNA into a mouse.

Jaenisch 2003 by Sam Ogden
Jaenisch 2003 by Sam Ogden

By 1976, the first company focused on this work, Genentech, was founded. In 1978, Genentech successfully produced genetically engineered human insulin.

Genetic engineering has many important applications in medicine and industry. In 1982, insulin-producing bacteria were commercialized for medical use. This technology is also used to create vaccines, such as mRNA vaccines for COVID-19. In industrial biotechnology, Chinese hamster ovary (CHO) cells are used for various processes. Scientists even use these techniques to produce enzymes for laundry detergent and cheese. In research, GMOs help scientists study gene function through experiments like loss-of-function or gain-of-function. By knocking out certain genes, researchers can create animal models to study human diseases.

Agriculture has also been transformed by these technologies. The first genetically modified food was the Flavr Savr tomato, sold in 1994. This tomato was engineered to have a longer shelf life. Today, most GM crops are modified to increase resistance to insects and herbicides. For example, the Bt potato was approved as a pesticide-producing crop in the US in 1995.

Bt plants
Bt plants

In 2009, transgenic crops were grown commercially in 25 different countries. Some of the largest areas of growth were in the United States, Brazil, Argentina, India, and China. Even pets have been modified, such as the GloFish sold in 2003.

Despite these benefits, the technology has faced significant controversy. Some people worry about food safety, gene flow, and the impact on non-target organisms. There are also concerns regarding the control of the food supply and intellectual property rights. These concerns led to the creation of a regulatory framework starting in 1975. In 2000, the international community officially adopted the Cartagena Protocol on Biosafety. While there is a scientific consensus that GMO foods are safe, individual countries have very different rules. For instance, there are marked differences between the regulatory systems in the United States and Europe.

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🖼️ Images & Media (8)
File:Breeding transgenesis cisgenesis.svg
Breeding transgenesis cisgenesis.svg
File:Jaenisch 2003 by Sam Ogden.jpg
Jaenisch 2003 by Sam Ogden.jpg
File:Master Mix with Primers form PCR.jpg
Master Mix with Primers form PCR.jpg
File:Genegun.jpg
Genegun.jpg
File:Agrobacterium-tumefaciens.png
Agrobacterium-tumefaciens.png
File:PCWmice1.jpg
PCWmice1.jpg
File:Expression of Human Wild-Type and P239S Mutant Palladin.png
Expression of Human Wild-Type and P239S...
File:Bt plants.png
Bt plants.png
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