- Slides: 26
Genetic Engineering Bioethics S
What is Genetic Engineering? S basic definition: genetic engineering is the direct manipulation of an organism's genes. S Genetic Engineering is useful in many fields including food production and medicine. S While it seems promising, there is still a lot that we do not know about Genetic Engineering.
Gregor Mendel S Gregor Mendel lived from 1822 - 1884 in Brunn, Austria. S He was an Augustinian Monk who taught natural science to high school students.
The “Father” of Genetics S Mendel was the first person to trace the characteristics of successive generations of living things. S Mendel wondered how plants acquired atypical characteristics. S Mendel performed experiments on pea plants, mice and ornamental plants.
Dominance and segregation of traits S Mendel crossed peas and mice of different varieties. S Through this experiment Mendel discovered the phenomena of dominance and segregation. S Dominance decides which characteristic most often surfaces; the dominant characteristic overrides the recessive gene and appears in the organism. S Segregation of genes decides which genes are inherited from the parents.
Laws of Heredity S Heredity factors do not combine; they are passed intact S Ex= A child of parents with black and red hair would inherit one of the two colors not a mix of the two. S Each member of the parental generation transmits half of its hereditary factors to each offspring S Different sets of offspring from the same parents receive different sets of hereditary factors S Ex= siblings are not identical, their differences come from the inheritance of different genes from their parents.
DNA S Discovered in 1869 S James Watson and Francis Crick discovered that DNA had a double Helix form. S Our DNA or genes decide who we are, they decide everything from our eye color to our shoe size.
DNA Engineering S We use recombinant DNA to manipulate genes. S Recombinant DNA is taking DNA from one source and inserting into another organisms DNA giving that being those characteristics. S Ex. = Inserting salmon’s anti-freezing genes into corn to allow it to survive frost.
Process of DNA Engineering S 1. Restriction enzymes cut DNA at their base parts causing sticky ends to form. S 2. DNA ligase (linker sequences of DNA) are placed on the sticky ends of the DNA. S 3. A Plasmid holding foreign DNA is inserted into the DNA and is connected by the ligase. (sticky end to sticky end) S 4. The recombinant DNA is inserted into a bacterium which carries out its function inside the larger organism. S 5. When the DNA becomes active it directs the body to construct distinct proteins which carry out the gene’s function.
Examples of Genetic Engineering Spider Silk S Creation of artificial spider silk by Nexia, a biotech company S Spider silk protein created by goats in their milk, then spun into silk S However, still not comparable to actual spidersilk
Insulin S Insulin—originally isolated from cows and pigs S 1982 – Humulin, a biosynthetic human insulin S Attempting to optimize insulin production by expressing them in different things S Insert human insulin gene into bacteria
Penicillin S Directed evolution of penicillin strains S Inserted genes to make erythromycin (penicillin substitute) into E Coli, which totally worked
Why do we. Genetically Engineer Foods? S Biotechnology is needed to feed the growing population of the world, especially the Third World. S Reduced chemical inputs, which will be good for the environment. S Genetic Engineering creates better yields in foods by giving them: S Pest resistance S Herbicide tolerance S Disease resistance S Cold/drought tolerance S More nutrition S Ability to replenish the soil they were grown in.
Engineered food-process S Biochemical ‘scissors’ called restriction enzymes are used to cut the strings of DNA in different places and select the required genes. These genes are usually then inserted into circular pieces of DNA found in bacteria. The bacteria reproduce rapidly and within a short time thousands of identical copies can be made of the ‘new’ gene. S There are now two principal methods that can be used to force the ‘new’ gene into the DNA of the plant that is to be engineered. A ‘ferry’ is made with a piece of genetic material taken from a virus or a bacterium. This is used to infect the plant and in doing so smuggle the ‘new’ gene into the plant’s own DNA. Or, the genes are coated onto large numbers of tiny gold pellets which are fired with a special gun into a layer of cells taken from the recipient organism, with any luck finding a hit somewhere in the DNA in the nucleus of the cells. S Genetically engineered animals and fish are produced by microinjection. Fertilized eggs are injected with new genes which will, in some cases, enter the chromosomes and be incorporated into the animal’s own DNA. Because the techniques used to transfer genes have a low success rate, the scientists need to be able to find out which of the cells have taken up the new DNA. So, before the gene is transferred, a ‘marker gene’ is attached which codes for resistance to an antibiotic.
Genetic Engineered Foods: Fears S"Human health effects can include higher risks of toxicity, allergenicity, antibiotic resistance, immune-suppression and cancer. As for environmental impacts, the use of genetic engineering in agriculture could lead to uncontrolled biological pollution, threatening numerous microbial, plant and animal species with extinction, and the potential contamination of nongenetically engineered life forms with novel and possibly hazardous genetic material. " (http: //www. centerforfoodsafety. org/gen eticall 7. cfm) SOther possible problems: SUnintended harm to other organisms SReduced effectiveness of pesticides SGene transfer to non-target species SAllergies SUnknown effects
Genetic Engineer Foods Case Study S Pusztai potato data S Pusztai reportedly fed rats potatoes genetically modified to have snowdrop lectin (which is an insecticide). the rats had stunted growth + immune system damage S Controversy: confusion over the lectin was from snowdrop (cool) or jackbean (poisonous) S research republished in october 1999, reviewed by 6 reviewers. “the paper did not mention stunted growth or immunity issues, but reported that rats fed on potatoes genetically modified with the snowdrop lectin had "thickening in the mucosal lining of their colon and their jejunum" when compared with rats fed on non modified potatoes“ S While the implications of this study are alarming, the study had a number of holes and its results cannot be taken to reflect for Genetic Engineering.
Genetic Engineered Foods Official Word on Safety S GM foods are highly regulated and they must pass extensive safety testing before reaching market. S GM foods have been consumed by hundreds of millions of people so far with no reported health problems to date. S Still it is possible that genetic engineering can unintentionally transfer allergens between foods. Also Genetic Engineering can create new allergens. S Genetic Engineering has only been around for 15 years. There are worries that long-term problems involving GM foods could be in our future.
Medical uses of Genetic Engineering S Pigs are often chosen as transgenic animals because their physiology and organ size are so similar to humans. The hope is that pig organs can be used for organ transplantation, known as xenotransplantation. S This will alleviating the shortage of human hearts and kidneys, which are in scarce supply. S Researchers are also exploring the use of cell transplantation therapy for patients with spinal cord injury or Parkinson’s disease. There are several drawbacks to xenotransplantation. S Additionally, commercial companies seek to derive therapeutic proteins, such as monoclonal antibodies, from the milk of transgenic cows, goats, rabbits, and mice and use them to administer drugs in treatment of rheumatoid arthritis, cancer, and other autoimmune disorders. 9
Medical uses of Genetic Engineering 2 S Other uses of this transgenic combination include growing tissue on a scaffolding, or supporting framework. This then can be used as a temporary skin substitute for healing wounds or burns or as replacement cartilage, heart valves, cerebrospinal shunts, or even collagen tubes to guide re-growth of nerves that have been injured.
Medical uses of Genetic Engineering 3 S Scientists harvest stem cells that can be used to study human development and to treat disease. Stem cells are important to biomedical researchers because they can be used to generate virtually any type of specialized cell in the human body. The extraction process destroys the embryo, which raises a variety of ethical concerns. S Ex= Stem cells since they are so versatile they can be created into cardiac tissue, spinal tissue and maybe even nerve tissue. Stem cells may be the key to curing diseases caused by the erosions of nerves such as Alzheimers and ALS.
Ethical problems S If the blending of nonhuman animal and human DNA results, intentionally or not, in trans-species entities possessing degrees of intelligence or sentience never before seen in nonhuman animals, should these entities be given rights and special protections? S It is possible that in blending DNA of different species we might be making our subjects susceptible to new forms of disease. S Could we inadvertently create a super-disease? S Is it right for parents to genetically alter their children before birth?
What is Synthetic Biology S Foundational Ideas S Automated DNA Construction S Standards of Abstraction S Goals S Organization of genetic information S Registry of Standard Parts S Built up through i. GEM S Open-source biological programming language S Scalable engineering framework
Banana Biobrick Transcription terminator for the E. coli RNA polymerase Promoter Ribosome binding site (lac. I regulated) T 1 from E. coli rrn. B alcohol acetyltransferase I; converts isoamyl alcohol to isoamyl acetate (banana odor)
Past projects S Synthetic blood S Banana E. coli S Arsenic biosensor S HIV “Virotrap” S Self-organized pattern formation