Genetic Engineering

1. Genetic Engineering MILLER-LEVINE BIOLOGY BOOK PAGES 247-259

2. BREEDING TECHNIQUES

3. Selective Breeding: Description:  The oldest and most obvious way of improving species  Select a few individuals to serve as parents for the next generation  Cross individuals with a desired trait Example(s): Luther Burbank produced 250 new varieties of fruit in addition to the daisy and Burbank Potato

4. Inbreeding: • Description: • Technique used to maintain a stock of similar organisms • Individuals with similar characteristics are crossed so the traits will appear again in next generation • PROBLEM: Increased risk of recessive genetic defects. Example(s): Purebred dogs

5. Hybridization: • Description: • A cross between dissimilar individuals of different, but related species • Offspring are often hardier than either parent Example(s): Commercially grown corn

6. Mutagens: • Description: • A breeder might not want to wait for a beneficial mutation to appear naturally. They catalyze this! • Mutagens include radiation and chemicals. They cause mutations • With luck and time, breeders end up with “good” mutants Example(s): Useful bacterial strains. Some bacteria can digest oil are are useful in cleaning up oil spills.

7. GENETIC ENGINEERING ARTIFICIALLY ALTERING GENETIC MAKE-UP, OFTEN USING DNA FROM ONE ORGANISM IN ANOTHER

8. STEP 1: ISOLATE THE DESIRED GENE • Restriction Enzymes: • Proteins that cut DNA sequences at specific regions • More than 75 are known • Each one recognizes a specific site of 4-6 nucleotide pairs and cuts • Make it possible to cut DNA into fragment that can be isolated, separated and analyzed

9. STEP 2: COMBINE THE GENE(S) WITH DNA FROM RECIPIENT ORGANISM • DNA Recombination: • Insert desired gene into organism--often bacterial plasmid (small circular pieces of bacterial DNA) • DNA now consists of parts from different kinds of organisms • This is “recombinant DNA”

10. STEP 3: INSERT COMBINED DNA INTO NEW ORGANISM • DNA Insertion: • It is easiest to transfer DNA into bacterial cells • Mix plasmids in with millions of bacteria in a salt solution • Altered plasmids will carry foreign DNA into bacterial cells • Bacteria are isolated and grown into large colonies to magnify the amount of the gene (DNA cloning) • Using different techniques, recombinant DNA can be inserted into yeast cells, animals and plants

11. GENETIC SCREENING DETERMINING THE NUCLEOTIDES ON DNA, USING GEL ELECROPHORESIS

12. READ NEW SEQUENCES OF DNA • DNA Sequencing: • Only one strand is used in DNA sequencing • Many copies of the strand are needed and produced via DNA cloning • Add radioactive phosphorus to DNA • Divide DNA into 4 groups that undergo different chemical treatments that break DNA into pieces • DNA pieces are separated by gel electrophoresis and banding patterns are analyzed to reveal sequence of bases

13. TRANSGENIC ORGANISMS ORGANISMS THAT CONTAIN FOREIGN GENES

14. BACTERIA: • Description: • Organisms that contain foreign genes are transgenic • When a gene coding for a human protein is inserted into bacteria, the recombinant cells may produce large amounts of the protein Example(s): Human growth hormone, Insulin to treat diabetes, Interferon to block growth of viruses and treat cancer

15. PLANTS: • Description: • DNA can be injected into plant cells directly or attached to plasmids of certain species of bacteria that infect plant cells Example(s): • The goal is to produce plants that manufacture natural insecticides and fertilizer • Firefly gene inserted into tobacco plant and it glowed!

16. ANIMALS: • Description: • DNA can be introduced into reproductive cells by injection, among other techniques Example(s): • Scientists introduced growth hormone gene from rainbow trout into carp. The new fish were bigger and faster growing. • Another goal is to produce farm animals that are resistant to disease.

17. CLONING The production of genetically identical organisms from single cells

18. CLONED ANIMALS: • Description: • The nucleus of an egg cell is removed and replaced with a nucleus taken from an adult organism • The egg is grown inside a foster mother • The newborn is a genetic copy of the adult from which the nucleus was taken Example(s): • In 1997 “Dolly” the sheep was cloned. Cows and mice have been cloned as well.

19. GENE THERAPY: Transgenic Humans Genetic Engineering to treat disease

20. GENETIC ENGINEERING IN HUMANS: • Description: • Transgenic humans can be produced by inserting foreign genes into human cells • Remove cells from an individual and grow them in culture. Transform with a corrective gene and reinsert • Viruses can be modified so they cannot cause disease Now that you have some scientific background you can make and support your arguments. Are you FOR or AGAINST GENETIC ENGINEERING? Example(s): • Cystic fibrosis, Tay-Sachs disease and sickle-cell anemia are examples of genetic disorders that could be treated in this manner

21. Legislative Analyst - presents the necessary scientific background required to understand the genetic engineering application and the proposition – the law that is being proposed. Paper and presentation should include: • Description of proposition • Explanation of SCIENCE background relevant to proposition • Proponent - presents the argument in favor of the proposition and the science supporting the proposition. • Paper and presentation should include: • Position (YES on proposition) • Explanation of SCIENCE in support of proposition • Relevant ethical issues related to proposition • Opponent - presents the rebuttal to the argument in favor of the proposition and the science against the proposition. • Paper and presentation should include: • Position (NO on proposition) • Explanation of SCIENCE against of proposition • Relevant ethical issues related to proposition