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Genetically Modified Organisms
Transcript of Genetically Modified Organisms
Genetically Modified Organisms
GMOs for Bioremediation
Organisms like bacteria can be used to clean up environmental toxins such as oil.
Genetically Modified Mammals
Genetically Modified Organisms-as a solution
GMOs hold great potential for nutrition and crop improvement, environmental clean up, and medical benefits. Many global health issues may be solved by the production of GMOs. However, the science must also be viewed with caution as any new technology should be. Potential impacts on human and environmental health caused by these organisms should be well-understood before they become widely used.
What are genetically modified organisms?
A GMO is a living thing which has had it's genetic material altered. Bacteria, yeast, plants and animals (even mammals) are all examples of living things that scientists have been able to genetically alter.
Global Health Issue #1
As the world's population grows, the need for food increases. Genetically modified crops could serve as a solution to the world food crisis by increasing crop yields and even growing more nutritious food.
Global Health Issue #2: Pollution and the environment
Genetically Modified bacteria and plants could possibly be used to turn toxic compounds into nontoxic products.
Genetically modified mammals could be used to create therapeutic medicines for humans.
Global Health Issue #3:
Treatments for human infectious disease and other health issues.
Genetically Modified Crops
What are genetically modified foods?
Watch this video to learn about how humans have been modifying their foods for centuries.
GM crops with pesticide resistance
Some plants have been genetically engineered to be resistant to pesticides. An example of this is "Round-up Ready" crops. This modification allows entire fields to be sprayed with Round-up, which will only kill the weeds and not the crop itself.
Bacteria are capable of breaking down naturally occurring pollutants such as oil, phosphates and some metals.
When oil-degrading bacteria are added to existing microbes, this is bioagumentation.
nutrients are added to stimulate the indigenous oil degrading bacteria.
Biostimulation has been more successful than bioaugmentation as the indigenous bacteria are often limited by the available nutrients.
This bacteria is capable of breaking down oil. Genetic modifications have been made to this bacteria to increase it's ability to break down oil.
So far, none of the genetic modifications have worked better than the naturally occurring bacteria. This supports this idea that the nutrients in the natural system are the limiting factor.
Phytoremediation is using plants to take up toxic materials. These are transgenic plants with a gene from bacteria added to the plant genome which is capable of breaking down a toxin.
Prospects for the future of bioremediation
How did they do it?
A donor egg is enucleated (the nucleus or genetic materials is removed)
A somatic cell (in this case mammary cell) is removed from a donor. The cloned sheep will be genetically identical to this donor.
The donor nucleus is fused with the enucleated egg.
The egg is now implanted in a surrogate.
Polly was the first transgenic cloned mammal. A human gene was integrated into her DNA. This was an important moment, because it demonstrated that animals could be used to produce human proteins.
Polly the Sheep
Polly produced the human protein Factor IX, a blood clotting protein used to treat hemophilia. The protein was secreted in Polly's milk.
3D image of Factor IX protein
How can genetically modified mammals be useful for human health?
Transgenic Genetically Modified mammals can be used to produce human proteins (like Polly did). These proteins can be used therapeutically.
Transgenic mammals can be used as disease models for vaccines or other therapies. Animals like sheep and pigs are more similar to humans than mice, and are therefore more useful models.
Xenotransplantation means transplanting cells and/or organs from one species to another. Animals can be genetically modified so their cells do not express the proteins that normally trigger an immune response (and therefore a rejection of the transplant) from humans.
Pigs are the most common animals used at this time for xenotransplantation. This is because their organs are of similar size and have similar plumbing to human organs. Scientists can knock out the gene that produces the molecules on the surface of the cell that cause an immune response.
Xenotransplantation: a genetically modified pig is used to create tissues and organs that can be used by humans.
Cell surface molecules can be "knocked out" in a GM pig.
How are GMOs relevant to Global Health Issues?
Some genetically modified crops are transgenic, like Bt corn, which includes a gene normally made by a bacteria, which causes corn pests to die if they consume the plant.
GM crops with pesticides
Bt corn may have unintended consequences on non-target species.
Cross-pollination could lead to weedy hybrids.
Pests may mutate and become resistant to the Bt corn (this has already happened in some locations).
Corn with it's own pesticides may have unknown health effects on humans, or cause allergies.
Round-up ready crops can encourage more spraying of pesticides.
Some crops have been genetically engineered to have added nutritional value. Golden Rice, for example, has added Vitamin A and is intended to help those populations that are deficient in Vitamin A.
GM crops with added nutrients
Other types of genetically modified crops...
Drought tolerant corn
Crops that can grow in poor soils
Rice with greater photosynthetic capability
Crops that fix their own nitrogen
Disease resistant Cassava
Cassava fortified with iron, protein and Vitamin A
Educational Policy Statement
Students will understand the science behind Genetically Modified Organisms.
Students will use the science of Genetically Modified Organisms to develop potential solutions for global health issues.
Next Generation Science Standards addressed:
HS-LS2-3.Construct and revise an explanation based on evidence for the cycling of matter and flow of energy in aerobic and anaerobic conditions.
HS-LS2-7.Design, evaluate, and refine a solution for reducing the impacts of human activities on the environment and biodiversity.*
HS-LS3-1. Ask questions to clarify relationships about the role of DNA and chromosomes in coding the instructions for characteristic traits passed from parents to offspring.
LS3.A: Inheritance of Traits
Each chromosome consists of a single very long DNA molecule, and each gene on the chromosome is a particular segment of that DNA. The instructions for forming species’ characteristics are carried in DNA. All cells in an organism have the same genetic content, but the genes used (expressed) by the cell may be regulated in different ways. Not all DNA codes for a protein; some segments of DNA are involved in regulatory or structural functions, and some have no as-yet known function. (HS-LS3-1)
What prior knowledge do students have of genetically modified organisms?
Students do not have much background knowledge related to GMOS, and what they have heard is related to agriculture.
What do teachers think students need to understand about GMOs?
Here are a few thoughts from another biology teacher.
Are genetically modified organisms ever justified, if so, when? Choose one of the examples from this lesson and explain why you believe that type of GMO should or should not be permitted.
GM crops could lead to decreased genetic diversity.
Growing food needs
Option #1: GMOs in agriculture
Genetically Modified foods are common. Do you feel that the use of genetic modification is justified in agriculture? Should genetically modified foods be labeled? If labels were mandatory, what information should be included? Design a label of your own.
Option #2: GMOs in bioremediation
Should scientists engineer bacteria and/or plants that can clean up human generated toxic compounds? Should a living organism be used to clean up our chemicals? Describe a potential application for bioremediation.
Option #3: GM Mammals
Should mammals like sheep and pigs be used as factories for creating human therapeutic proteins and organs for donation? Design an advertisement for pig organs available for transplant.
by Kathryn Davis