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Biotechnology Technique #3: Genetic Engineering • Use the slides that follow to fill in the notes on page 6 of your note packet. This is Buckey and Tucker alongside their mom. Buckey and Tucker have been genetically engineered so that their female offspring will produce a specific protein in their milk. There are several ways that organisms can develop new traits: • • • • natural selection mutation selective breeding genetic engineering • We’re going to look at the last two in this chapter. Selective Breeding • Selective breeding = artificial selection (instead of natural selection) • Process of breeding plants or animals for specific traits • animals = breeds • plants = varieties or cultivars With selective breeding… • Humans take control; we choose the traits that we want the offspring to have: – Identify the feature that we want – only allow individuals with that feature to breed with one another • We’ve been doing this for 1000s of years! – crops – domesticated animals Examples • Farmers select for cows that produce more milk or for corn plants that produce corn with larger ears • Dog breeders Genetic Engineering • Genetic engineering = altering the DNA of living organisms • Requires recombinant DNA • Recombinant DNA (rDNA) is DNA from two or more sources incorporated into a single recombinant molecule • Organisms with rDNA are genetically modified organisms (GMOs) • Has both medical and agricultural applications! • Use the slides that follow to fill in the information on page 7 of your note packet. This is Dolly, the first successfully cloned organism, and her lamb, Bonny. Medical Application 1 • Gene therapy – Isolate healthy functional gene – Insert healthy gene into a vector like bacteria or a virus – Infect a patient with the vector to introduce the healthy gene – The healthy gene should produce a normal protein that replaces the function of the patient’s abnormal protein • Works well for disorders resulting from loss of single proteins • Gene therapy is a possible treatment for people suffering from cystic fibrosis, hemophilia, possibly AIDS and some cancers • Cons: – treatment must be repeated – immune reactions Medical Application 2 • Cloning – whole organisms = cloning by Somatic Cell Nuclear Transfer (SCNT) • 1st done in 1996 – Dolly • Died of premature aging and disease • 6 yrs old – about ½ the normal life span • Goal is to alter genome in a useful way – Exp. altered/cloned goats secrete human clotting factors – Altered pigs may produce organs for transplant that don’t trigger rejection Medical Application 3 • Vaccines – Some vaccines contain genetically altered pathogens so they do not cause disease but the body sill builds up antibodies/immune response against the pathogen in the future • Exp. DNA vaccines have pathogen DNA but no disease-causing capabilities • Possibilities: AIDS, malaria, cancers Medical Application 4 • Genetically engineered bacteria can become like little “protein factories” that produce human proteins • Scientists can isolate and purify these proteins for human use – Exp. insulin for diabetics • There are over 30 products made this way for medical use! A Few Recombinant DNA products: • • • • • • • • • Insulin – for diabetics Factor VIII and factor IX – clotting factors for hemophiliacs Human growth hormone – for growth defects Erythropoietin – for anemia Interferons – for viral infections and cancer Interleukins Tissue plasminogen activator – dissolves blood clots Angiostatin and endostatin – cancer drugs Hepatitis B surface antigen – for hepatitis B vaccine Agricultural applications • Genetically modified organisms (GMOs) include crops and livestock. Agricultural applications • Genetically modified crops have been genetically altered to: – be more tolerant of environmental conditions – be resistant to insects/pests and herbicides (weed killers) • Have genes that code for proteins that are harmful to insects/pests – be resistant to plant diseases – increase the amount of food a crop will yield – improve nutritional value GMOs • 93% of soy • 94% of cotton • 88% of corn • GMOs in > 80% of packaged products! • Although polls consistently show that American consumers would like to have foods labeled as containing GMOs, there are no mandatory labeling laws. • Livestock have been genetically altered to – Increase milk production – Increase growth rate – Be more resistant to infections – Produce leaner meat • No GM animals have been approved for food by the FDA yet… • Remember Buckey and Tucker? They’ve been engineered so that their female offspring will produce spider silk protein in their milk. • Huh?! Why? That sounds weird. • These proteins can be used to spin silk fibers needed to make artificial limbs and bulletproof vests! Why the controversy over genetic technology? • GM crops can get into the wild and become a “SUPERWEED”! • Gene therapy shouldn’t involve reproductive cells that could affect future generations. • Human embryos should not be cloned. • Confidentiality is key. Knowing an individual’s genetic make up may lead to discrimination in the workplace. • As much as 70-75% of food in supermarket may be genetically modified. The US does not require GM foods to be labeled. The End!! Thank you for completing your notes!!