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Lesson Overview. 15.1 Selective Breeding. Show short videos from Nova. REVIEW. What are the two things that can get mutated (when talking DNA)? Yes! Genes & Chromosomes Did you know that some people make MUTATIONS on purpose?. THINK ABOUT IT. Where does popcorn come from?
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Lesson Overview 15.1 Selective Breeding Show short videos from Nova
REVIEW • What are the two things that can get mutated (when talking DNA)? • Yes! Genes & Chromosomes • Did you know that some people make MUTATIONS on purpose?
THINK ABOUT IT • Where does • popcorn come from? • Earliest Ex of efforts to select/improve living orgs for our benefit! • Bred teosinte • Popcorn—5000 years old!
Selective Breeding • Breeding to pass on traits they want (done for 1000s of years) • Examples: • Farm animals, dogs, horses, crop plants (corn, soybeans, cotton) • Why? • Produce “disease or pesticide resistant” • “bigger”, “better” heartier species • Less land/energy, no chems & CHEAPER! Types of GMF's
2 Methods 1. Hybridization: Crossing dissimilar individuals to bring together both of their best characteristics • Ex: • Plant 1: Has disease resistance • Plant 2: High food-producing capacity • RESULT: A new line of plants for farmers & consumers! • Luther Burbank (800 new plant varieties)
2 Methods 2. Inbreeding:Maintains desired characteristics using similar organisms & develops pure lines. • Example: • Pure Bred DOGS • AKC • RISK? • May bring 2 recessive alleles for a genetic defect. • Blindness • Joint deformities
Increasing Variation… • HOW? • By using radiation and chemicals (> rate) • Creates a few desirable mutants • RISK? • Possibly be very harmful to an animal • Can create non-desirable mutants!
Biotechnology • Application of a technologicalprocess, invention, or method to living orgs.
Polyploid Plants • Larger/Stronger • Drugs prevent separation of chroms. during meiosis • Many times normal # of chroms.
Lesson Overview 15.2 Recombinant DNA
THINK ABOUT IT • Suppose you have an video game you want to change. • So…the game depends on a “coded program” in a computer microchip • You’d need a way to get existing program out of microchip, read program, make changes you want, and put modified code back into microchip. • What does this have to do with genetic engineering? Just about everything.
Copying DNA • How do scientists copyDNA of living orgs? • It is relatively easy to extract DNA and cut into fragments (Using ___________enzymes)
Finding Genes • Douglas Prasher, MASS. Biologist (1987) • Jelly Fish Story (GFP-Green Flourescent Protein) Gets E from light to glow, add GFP gene (attaching light bulb to molecule)
Polymerase Chain Reaction (PCR) • Once biologists find a gene, PCR allows them to make many copies (4 steps). • 1. DNA heated (2 strands). • 2. Primer (short piece of DNA) added to each end • 3.DNA polymerase copies between primers (templates) • 4. Billions of DNA copies
Is it possible to change the DNA of a living cell? • Griffith did it w/bacterial transformation…
Scientists can produce custom-built DNA molecules in lab & insert into living cells • Recombinant-DNA technology—joining together DNA from 2+ sources (using DNA ligase)
Plasmids & Genetic Markers • Some bacteria contain small circular DNA molecules (plasmids) • Put recombinant DNA into ring of DNA
Transgenic Organisms • “Containing genes from other species” • Orgs produced by insertion of recombinant DNA into genome of host
Gene Therapy(How to get the “cool” gene!) • 1. Isolate foreign DNA fragment to be inserted • Use “restriction enzymes” to CUT DNA out • Like zipper (but only at certain spots-SNP) • 2. Attach DNA fragment to Vector (carrier) • viruses & plasmids • 3. Transfer into host organism • Cells “cloned” w/ normal mitosis Do play w/ Rest. Enz., Org 1, Host Or & Vector
The Liger…. 52:21 to 56:49 on Spy Kids II
Cloning • *Genetically IDENTICAL cells produced from a SINGLE cell. • Nuclear Transplantation (1st remove egg’s nucleus) • 1952-Amphibian Tadpoles • 1997-Wilmut: Cloned an adult cell (Dolly) who created Bonnie & triplets. • Cows, pigs, mice, etc. Plants/bacteria easy.
Cloning • Reason: Hoping for medical/scientific value • Pro • Help save endangered species • Cure diseases • Make duplicate organs and prized animals • Create people/animals w/o certain diseases • Con • Problems are unknown! • If cloning humans, is this morally “right”?
Lesson Overview 15.3 Applications of Genetic Engineering
THINK ABOUT IT • Have you eaten any GM food lately? • 86% Corn, potatoes, or soy products 2008 meat/milk, 100% chance, eat/wear,
Agriculture and Industry • Genetic modification could lead to food: • 1. better (Ex: Insect Resistance/Herbicide Tolerance) • 2. less expensive • 3. more nutritious & • 4. less harmful manufacturing processes.
What ELSE? • Cows- 30% U.S. milk w/hormones • Pigs-leaner meatw/ omega-3 acids. • Salmon-growquickly! • Goats-Produce silk(spider genes) in milk . • Golden rice-vitamin A • Sheep/pigs milk produce human proteins (easy to collect/refine)
Treating Disease • Substances mass-produced by recombinant genetically-engineered (GE) bacteria • Human Growth Hormone • Insulin • Blood-clotting factors • Interleukin-2 and Interferon