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) 1 st 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!!