GENETIC ENGINEERING

1. GENETIC ENGINEERING

2. That's Unbelievable! Genetic engineering examples include taking the gene that programs poison in the tail of a scorpion, and combining it with a cabbage.  These genetically modified cabbages kill caterpillers because they produce scorpion poison (insecticide) in their sap. Potatoes have been engineered to resist pests by producing a chemical coded for by a frog gene. Genetic engineering also includes insertion of human genes into sheep so that they secrete alpha-1 antitrypsin in their milk - a useful substance in treating some cases of lung disease. Genetic engineering works because there is one “language of life”(universal genetic code):  human genes work in bacteria, monkey genes work in mice, pepper plant genes work in bananas and spider genes work in goats.  There is no limit, in theory, to what genetic engineering could produce! Genetic engineering has created a chicken with four legs and no wings. Scientists were studying the genes that control limb formation in embryo development.

3. What is genetic engineering? • the use of technology to change the genetic make-up of cells to produce a new and useful result

4. Is genetic engineering a new idea? • Humans have been selecting and breeding organisms with desired traits for thousands of years. Some examples: • “Seedless” oranges • Pluots: Plum-apricot hybrid

5. Comparing selective breeding and genetic engineering In selective breeding (think Mendel’s peas), we are combining two traits to get a mixture of results In genetic engineering, a single gene, a half page recipe in the 52-thousand-page set of recipe books, can direct the plant to make new traits or remove them Comparison

6. How does genetic engineering work? • First, a desired gene in an organism must be identified and isolated. • Once isolated, the gene is further modified in the lab • The modified gene is inserted into a vector (like a bacterium or virus) and the vector “delivers” the gene to the desired organism. http://cmbi.bjmu.edu.cn/cmbidata/therapy/research/re02/021.htm

7. How it works:

8. Example: Insulin Production • Protein that codes for insulin production is cut from human DNA using restriction enzyme (EcoRI)

9. Example: Insulin Production • Plasmid (from E.coli) is also cut with EcoRI • Sticky ends are now exposed on both human DNA and plasmid DNA

10. Example: Insulin Production • Ligase seals sticky ends of desired DNA and plasmid DNA • Recombinant DNA is inserted into a bacterium

11. How Did They Do That? • Jellyfish make a protein that causes them to glow in some types of light. • The glowing gene is taken from a jellyfish cell and inserted into an empty virus cell • The genetically engineered virus attaches itself to the fertilized mouse egg cell. • The virus delivers the glowing gene into the egg cell nucleus, where it joins the mouse DNA. • The genetically engineered mouse egg grows into an adult mouse which will make the glowing protein. Jellyfish cell Virus Virus inserting their DNA into a cell Mouse cell

12. Extended shelf-life tomato (Flavr-Savr) Herbicide resistant soybean (Roundup Ready) Transgenic Organisms • Any organism that contains genes from a different organism (traits not normally found in that species) is a transgenic organism.

13. What are some possible uses of genetic engineering? • Improving crops • Creating bacteria that can produce medicine • Increasing food supplies • Alternative energy sources • Human body parts for transplant • Preventing human diseases (gene therapy)

14. Improving Crops • Crops may be improved by making them resistant to certain factors, like insects, drought, herbicides, or frost • Crops may also be “improved” by engineering them to produce things like vitamins that are not normally found in the species

15. Agriculture Transgenics On the Market • Insect resistant cotton – Bt toxin kills the • cotton boll worm • transgene = Bt protein Source: USDA • Insect resistant corn – Bt toxin kills the • European corn borer • transgene = Bt protein Bt Corn Normal Transgenic

16. Herbicide resistant crops • Now: soybean, corn, canola • Coming: sugarbeet, lettuce, strawberry • alfalfa, potato, wheat (2005?) • transgene = modified EPSP synthase or • phosphinothricin-N-acetyltransferase Source: Monsanto • Virus resistance - papya resistant to • papaya ringspot virus • transgene = virus coat protein

17. Fishy Strawberries- Making a frost resistant strawberry 1. Fish antifreeze gene is inserted into a plasmid. The flounder is a fish that live in icy seas. It has a gene that stops it from freezing to death. Strawberries are soft fruits that can easily be damaged by frost. 2. Plasmid with gene is placed into a bacterium. 3. The bacterium with the flounder gene is used to “infect” strawberry cells. Strawberry cell with Antifreeze gene 4. The infected cells grow into a frost-resistant strawberry plant.

18. Golden rice is genetically modified to contain large amounts of beta-carotene, which is converted by the body into vitamin A Vitamin A is important to factor for good vision (particularly night vision) and a strong immune system. Many individuals in poor and underdeveloped countries receive inadequate amounts of vitamin A in their diets, leading to higher incidences of blindness. Can genetic engineering end malnutrition and vitamin deficiencies? Golden rice

19. Creating bacteria that can produce medicine • As you saw in a previous example, bacteria have already been engineered to produce insulin proteins that can be injected by human diabetics to control their diabetes. • Some other examples: • Bacteria produce human growth hormone to treat types of dwarfism • Producing interferon for cancer treatments

20. Increasing Food Supplies • In many parts of the world, hunger is rampant due to limited food resources. • One possibility is to produce fish species that mature more quickly so that they can breed and create new generations sooner. Salmon http://fish.dnr.cornell.edu/nyfish/Salmonidae/salmonidae.html

21. Alternative Energy Sources • Fossil fuels are dwindling • Ethanol (the current alternative) comes mostly from corn, which is used as a major food crop in most countries • It would be most beneficial to use “waste” and “leftovers” for fuel. Ethanol

22. Creating Human Body Parts for Transplant • Individuals in need of an organ transplant can often wait years for a donor organ. • Organs from other species is not usually an option because the immune system attacks such transplants as “foreign”. • Scientists are researching the possibility of inserting human genes into other species so that they can grow “human” organs for transplant.

23. Photo of mouse growing a "human ear" - a shape made of cartilage What’s Going On Here?

24. Some Other Possibilities • Earlier this decade, scientists at the University of Minnesota created pigs that pumped human blood (specifically human hemoglobin)

25. Preventing and Curing Human Diseases • Several human diseases (like cystic fibrosis or breast cancer) have a genetic component. • Individuals with these disorders have a mutation, or mistake, somewhere in their DNA sequence • Replacing these mutated sequences with “normal” sequences should fix the problem • This process is known as gene therapy.

26. Patient’s cell Patient’s DNA Faulty Gene Virus DNA New working gene Patient’s DNA Virus DNA with new gene What is Gene Therapy? • Individuals with cystic fibrosis have a faulty gene. • To fix the problem, a copy of the same gene from a healthy person is spliced into a virus. • The patient’s lungs are infected with the virus. It delivers the working gene into the patient’s cells. The cells can then make the right protein, and the patient can breathe normally. Alzheimer’s Disease

27. Lung cancer cells (530x). These cells are from a tumor located in the alveolus (air sac) of a lung. Will We Be Able To Cure Cancer With Gene Therapy? Cancer happens when body cells grow out of control. Scientists have found a gene called p-53 which normally keeps cells under control. Some individuals with cancer may have a non-working copy of p-53. Experts are now looking for a way to cure cancer by modifying faulty DNA to make the p-53 gene work. Breast Cancer

28. What Else? Using the jellyfish protein to make a naturally glowing Christmas tree! Genetically engineered moths that pass on deadly disease genes to their relatives so they die and won’t be able to destroy crops! A gene from a spider has been inserted into some goats. Their milk now contains tiny strands of spider silk which can be made into a strong, stretchy rope. Adding a gene from insect killing bacteria to cotton so that insects who eat cotton will be poisoned! This is only the beginning . . . !