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Genetic Engineering
Def: the artificial manipulation or alteration of genes.
AKA: Genetic manipulation, genetic modification, recombinant DNA technology, genetic splicing & gene cloning
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Genetic Engineering Breaks the Species Barrier
- Human genes inserted into bacteria
- Bacterial genes inserted into plants
- Human genes inserted into other animals
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Tools Used in Genetic Engineering
- A source of DNA – Foreign DNA, from an organism
- A cloning vector – accepts DNA and replicates it eg. Bacterial plasmid
- Restriction Enzyme – cuts DNA in specific places, acts like a genetic scissors
- DNA Ligase – ‘glue’ foreign DNA to join with the DNA of the cloning vector
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Restriction Enzymes & DNA Ligase
- Restriction Enzymes
- Only cut DNA at particular sites (restriction site)
- If DNA from 2 different organisms is cut with the same restriction enzyme, the cut ends from both sources will be complimentary
- DNA Ligase
- Enzyme that sticks DNA molecules from different sources firmly together
- Will only work if both DNA have been cut by the same restriction enzyme
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The Process of Genetic Engineering
- 1. Isolation
- Removal of both human DNA containing target
- gene from its chromosome and plasmid DNA from bacterium
- 2.Cutting
- Human DNA and plasmid DNA are cut using the restriction enzyme at recognition site
- 3. Ligation
- Target gene is placed into the DNA of the
- plasmid or cloning vector and joins (glues) onto it using DNA Ligase
- 4.Transformation
- This is the uptake of DNA into a cell. Only about 1% of bacterial cells take up plasmid and target gene.
- 5. Cloning
- Identical copies of the bacterium are produced using a nutrient medium
- 6. Expression
- Getting the organism with the recombinant DNA to
- produce the desired product
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Applications of Genetic Engineering
Plant: Bacterial genes are added to crop plants so they will have resistance to herbicides
Animal: Some people can’t reproduce a protective protein (ATT) in their lungs leading to collapse of alveoli, a condition known as emphysema. ATT is inserted into sheep DNA and sheep produce the protein in their milk.
- Micro-organism: Human insulin is inserted into bacterium which reproduces large quantities of insulin
- used by diabetics
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Ethical Issues in Genetic Engineering
- Fear that animals will suffer
- Fear that humans may be genetically modified
- Use of GMOs as a food source
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