Genetic Engineering

Biotechnology and Recombinant DNA

Biotechnology

The use of microorganisms, cells, or cell components to make a product:• Foods• Vaccines• Antibiotics• Vitamins• Biodegradation

Genetic Engineering

• Manipulating an organism’s genome to:• alter microbes, plants, and animals

for our benefit

• correct genetic defects in humans

Ex: Golden Rice

• Created to provide people with Vitamin A

• Developed to help the very poor

Ex: Flavr Savr Tomato

• Created to prevent the softening of the tomato

• Made more resistant to rotting

• Could be “vine-ripened”

Ex: Glofish

• Inserted fluorescent gene from a jellyfish into zebrafish

• Sold as a pet

Ex: Roundup Ready Soybeans

• Soybeans that are resistant to Roundup herbicide

• Created to reduce the application of harmful herbicides

Bioethics Warm-UpWhich human traits do you think are acceptable to genetically modify?

Which human traits aren’t acceptable to genetically modify?

Bioethics Warm-Up

Would you want to know if you were genetically predisposed to a certain disorder (like heart disease or diabetes)?

What if it was for a disorder that has no known treatment?

Glowing Animals

Other Uses of Genetic Technology

• Used to identify individuals:– Suspects in a crime (“DNA fingerprinting”)

Other Uses of Genetic Technology

• Used to identify individuals:– Relation between

individuals:• Ex: paternity tests

Other Uses of Genetic Technology

• Used to identify individuals:– Relation between

individuals:• Ex: University of

Arizona Shoah Project to identify and reunite the families of Holocaust victims

DNA

• DNA is universal – the genetic information from one species will work in another species

• “DNA is DNA”

DNA 101 – Quick Refresher

• DNA formed from units called nucleotides

• Each nucleotide is made of:– 5 carbon sugar (deoxyribose)– Phosphate group– Nitrogenous base

• Adenine• Guanine• Cytosine• Thymine

DNA 101 – Quick Refresher

• In all DNA:– A pairs with T– C pairs with G

• Weak hydrogen bonds form between complimentary base pairs

Bioethical Question

• Should a company be allowed to patent (and own the exclusive rights of) a genetically modified organism?

Useful Properties of DNA

• Restriction Endonuclease – enzymes used to cut apart DNA strands

Useful Properties of DNA

• Restriction enzymes can cut DNA at specific sites, leaving “sticky ends” for insertion of new DNA

• Ligase – enzyme used to “glue” strands together

DNA Manipulation

Restriction Endonucleases

• Also called restriction enzymes• 1962: “molecular scissors” discovered

in in bacteria• E. coli bacteria have an enzymatic

immune system that recognizes and destroys foreign DNA

• 3,000 enzymes have been identified, many are purified and available commercially

Restriction Endonucleases

• Named for bacterial genus, species, strain, and type

Example: EcoR1

Genus: EscherichiaSpecies: coliStrain: ROrder discovered:

1

“Sticky Ends” vs. “Blunt Ends”

Restriction Endonuclease

• Restriction enzymes recognize specific palindromic sequences and cut them– Palindromes: words that are the same

forwards and backwards• Ex: Stanley Yelnats• Ex: Go hang a salami, I’m a lasagna hog• Ex: Anna• Ex: A man, a plan, a canal, Panama!• Ex: Wet sanitary rat in a stew.

Bioethical Issues

• Should we be able to insert non-human DNA into human DNA?

• Would this change what it means to be “human”?

• Should humans be able to alter our intelligence via genetic engineering?

Warm-Up

• If there aren’t any risks associated with GM foods, should companies be required to label foods made with GMOs?

Recombinant DNA

• Recombinant DNA: DNA from two or more species that has been joined together

• Transgenic: organisms altered by genetic engineering

Warm-Up

• Genetic pollution: undesired and uncontrolled gene flow from GMOs into wild populations

• What are the implications of “genetic pollution”?• Should we try to prevent “genetic pollution”?

Other Uses