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Transcript of Genetic Engineering
For more than a decade, researchers have investigated whether genetically modified or transgenic plants could help clean up contaminated sites by taking up pollutants using their roots. The genes that researchers put into these plants could then break down molecules such as carcinogens, or cancer-triggering molecules."So many of us have been impacted by cancer that I am strongly motivated to find ways to reduce the amount of carcinogens from our environment in a fast and economical way," said researcher Sharon Doty, a plant biologist at the University of Washington.
What is genetic engineering?
Genetic engineering is the deliberate modification of the characteristics of an organism by manipulating its genetic material.
It is carried out by physically removing a gene from one organism and inserting it into another. This gives the organism with the new DNA the ability to express the trait that is coded by that gene.
The process of genetic engineering is as follows:
First, an organism that naturally contains the desired trait must be present.Then, the DNA is extracted from that organism. Restriction enzymes help to remove the desired gene from the DNA.
Plasmids are removed from bacterial cells and are cut by restriction enzymes. The gene is inserted into the plasmid to form a “recombinant”. DNA ligase attaches the gene to the plasmid at the sticky ends.
The recombinant gene is absorbed by bacteria through transformation. The gene becomes a part of the bacterias DNA. After that, the bacteria is inserted into the host.
Once, in the host, the bacteria will multiply rapidly causing the host to produce proteins that are coded by the new gene.
Genetic Engineering in Plants
During the 1950's, a pathogenic fungus, Endothia Parasitica, caused a fast, widespread wipe-out of these trees in the eastern U.S. Chestnuts are keystone species. They provided food to wildlife such as caterpillars, birds, bears, etc. Part of the American Chestnut Research and Restoration Center, Charles Maynard and William Powell, SUNY College of Environmental Science and Forestry (ESF) professors, have genetically engineered an American chestnut tree that is resistant to these plant diseases.
This tedious procedure requires years of trial-and-error. Different genes had to be inserted and also had to be grown into trees large enough to experiment on. The first blight resistant chestnut tree was inserted with a resistance gene from wheat. This discovery can help save the diminishing population of the trees. The resistant gene can be passed down to next generations easily through production of their nuts. These plants have to go through some federal agencies and the government before it can be planted back into the ecosystem.
Doty, bioremediation researcher Stuart Strand and their colleagues have created genetically engineered poplar trees in the laboratory that can remove as much as 91 percent of trichloroethylene — the most common groundwater contaminant at U.S. Superfund sites — from liquids. Unaltered plants removed 3 percent.The modified poplars generate a lot more of a key enzyme, and work more quickly. They break down the dangerous molecule into harmless byproducts about 100 times faster than normal plants.
"Scientists have experimented with using plants to clean up the environment in the past, a technique known as phytoremediation."Phytoremediation is basically a solar-powered pollutant removal system," Doty said. "It is more than 10 times cheaper than other technologies. It is less intrusive and more aesthetically pleasing."However, "phytoremediation is often viewed as being too slow to be of practical use," Doty said. "Many sites are abandoned rather than cleaned up because of the cost of effective cleanup. It is for this reason that we became interested in enhancing phytoremediation using transgenic technologies."
Genetic Engineering in Animals
Steve Goldman, from the University of Rochester Medical Center in New York, first injected glial cells into mouse pups from human fetuses. The glial cells help support the neurons and form the myelin sheath around the nerve cells. The cells developed into astrocytes, a star-shaped glial cell. As a result, the mice were much smarter than the mice without the human astrocytes. This is because the astrocytes are vital for conscious thought, helping to strenthen connections between the neurons. The tendrils from the astrocyte help coordinate the transmission of electrical signals across the synapses. Therefore, the mice with hybrid human brains learned faster, navigated mazes better and had better memories than the mice without the modified brains.
In an another experiment, mouse pups that were poor at making myelin, a protein that insulates the nerves, were injected with the human glial cells. The cells matured into oligodendrocytes, which helps with the production of myelin. This discovery is useful for treating diseases where the myelin sheath is damaged, such as multiple sclerosis. These experiments alter the mice brains to be more similar to humans so it can help us understand the human brain more. From this, we can get more medical research about human brain diseases and other neurological disorders. “The goal was not to create a new species of ‘supermouse’ but rather to make the brains of mice more humanlike so that scientists can advance their understanding of brain disease".
The Enviropig pig was developed by, and the technology is owned by, researchers at the University of Guelph in Ontario. Enviropigs are the world’s first transgenic animal able to digest phosphorus in cereal grains, providing the ability to increase nutrient value from plant feedstuffs. These pigs produce the enzyme phytase in the salivary glands that is secreted in the saliva. When cereal grains are consumed, the phytase mixes with the feed as the pig chews. Once the food is swallowed, the phytase enzyme is active in the acidic environment of the stomach, degrading indigestible phytate in the feed that accounts for 50 to 75% of the grain phosphorus.They are “environmentally friendly” animals.
Enviropigs have a special gene that allows them to produce manure that is lower in phosphorus content. Even though phosphorus is a essential nutrient for animal and plant growth, excess quantities of phosphorus in the environment causes major pollution. It is a big problem around the world. Having a pig that produces manure with lower phosphorus content and increased nutrient value is beneficial for the environment especially in more populated countries with less available land for livestock and for spreading manure.
Phytase produced in the salivary glands and secreted in the saliva increases the digestion of phosphorus contained in feed grains.
French scientists and investigators from Aix-Marseille University, hospitals in Marseille, the University of Paris Est and the Vaccine Research Institute in Creteil researched about a case study of two people who have HIV, but didn't show any symptoms. The men were diagnosed with HIV but they had no HIV-related disease and detection in their blood. Studies show that there was a mutation in genetic code of the HIV virus so it wasn't able to replicate. Many of the codons are transformed into stop codons. The mutation may have been caused by the increase of the enzyme APOBEC. This discovery helps us understand the virus better and offers a new strategy in the fight against AIDS. The strategy suggested that the virus cannot be completely gone but can be inactivated to produce the apparent immunity of the HIV infection.
Genetic Engineering in Humans
Researchers from Sun Yat-sen University have successfully genetically modified a human embryo. Their goal was to knock HBB, a gene that causes a fatal blood disorder. The researchers used the CRISPR technique that uses an enzyme complex to bind and splice out faulty gene segments and replace them with functional DNA segments. These genetic modifications can lead to medical techniques that can get rid of genetic disorders, for example down syndrome, before a person in born. The experiment used 86 embryos. 71 survived the CRISPR technique and 54 were genetically tested. Of those, only 28 were successfully spliced. The experiment is not 100% successful, but some embryos were successfully modified and contained the replacement genetic material.
The threat of global climate change has inspired people to redesign many of our technologies to be more energy-efficient. Some scholars, professors and scientists believe that doing so will only get us so far and we could take it a couple of steps further by engineering human beings to be more energy efficient and combat climate change.
The U.N. Food and Agricultural Organization say that around 18% of the world's greenhouse gas emissions come from livestock farming, which is a much higher amount than from transportation. More recently, it's been said that livestock farming accounts for as much as 51% of the world's greenhouse gas emissions and then 9% of human emissions are the results of deforestation for the expansion of pastures for livestock. Since many of these cows and other grazing animals are raised for consumption, many scientists believe that reducing the consumption of these meats would greatly benefit the environment.
Another strategy scientists are proposing is for humans to be more energy efficient and battle climate change is to modify ourselves to become smaller. Since larger people consume and require greater amounts of energy, nutrients and resources than smaller people, engineering humans to become smaller in size would help save a lot of energy. There are several ways of carrying out this process, one being a technique called preimplantion genetic diagnosis. Using this technique, embryos being implanted could be selected based on height. Another method to make humans smaller is to use a hormone treatment where a hormone would be injected into individuals, which would close the epiphyseal plate earlier than normal and stop further growth. Hormone treatments are currently being used to reduce the heights of children that are too tall.
Another method being discussed is the consumption of drugs such as empathy-increasing drugs that will help humans to be more empathetic to each other and the environment. Scientists believe that the consumption of such drugs would lead humans to take better care of the earth.
Another interesting method being discussed is genetically engineering humans to have cat eyes. Cats have as nearly as good of eye sights as humans do during the day; however, they have better vision during the night. Even though science didn’t go that far, scientists and researchers are looking into ways to genetically engineer humans to have more cat-like eyes or eyes of other primates with good vision in the dark. The genes that are responsible for the trait need to be found and then activate them in humans. Humans having better vision would decrease the need for light and save energy.
Since many people are'nt willing to give up eating meat, scientists suggest that people could take a pill that would trigger mild nausea when eating meat. This would lead to a lasting reduction of meat consumption result in a reduction of greenhouse gases.
Some scientists suggest humans adopting something similar to China’s one child policy around the globe would help lower the human population size and the use of energy and resources. People can have the choice of having children such as three small children or one huge child.
Pros and Cons of Genetic Engineering
Decreases the extinction of species
Aids in research and progression in understanding of different living organisms
Helps the economy (biotechnology)
Produces new mutations and diseases
Unknown effects in populations and ecosystems
Unnatural , ethical concerns