In a way, humans have been genetically engineering foods and animals for thousands of years…

Crossing two parents who are dominant for desirable traits such as high crop yield, resistance to disease, long life, “sociableness” (in animals like dogs and cats), or high milk production (in cows, etc.).

Selective Breeding:

May lead to low genetic variability…

Genetic Engineering:

crossings.tcd.ie/ gallery/Kac/Eighth_Day/

National Geographic article about glowing mice

These mice have been inserted with a jellyfish gene which allows them to fluoresce under special light sources. Normal mice appear black under the same light.

Moving the DNA of one organism to another organism, not necessarily of the same species.

The mouse on the right has been genetically engineered.

GMO= Genetically Modified Organism

Any organism that has had their DNA changed with biotechnology is considered a GMO.

We eat many GMOs: http://www.truefoodnow.org/shoppersguide/guide_printable.html

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

http://tlc.discovery.com/convergence/superhuman/photo/zoom_03.html

Mouse and Human EarLooking more like the handiwork of a mad scientist, this mouse actually served as a host for growing a human ear. Dr. Charles Vacanti of the University of Massachusetts implanted a scaffold, or mold, in the shape of a human ear on the back of the mouse. The scaffold was made of fine strands of a new kind of biodegradable plastic and seeded with living cells. The living cells adhered to the plastic fibers as they grew and took on the shape of the mold. In time the plastic mold dissolved, and the living cells took over and generated new tissue; the new tissue in this case being a three-dimensional, contoured ear. Where does the mouse come in? ... The mouse provided the warmth and nourishment for the growing cells.

Genetic Engineering??? Not really…

So how is Genetic Engineering done?

•First, scientists have to isolate (separate it from other DNA) the gene or genes of interest

•This may take years of research•Then, copies of the gene are made to make scientific study easier…

•PCR: Polymerase Chain Reaction

PCR can also be used with a very different scenario…A tiny drop of blood that may belong to a suspect is found at a crime scene. There is not enough of the sample for forensic scientists accurately analyze. What can they do?

http://newmiller.com/CrimeScene/images/b10.JPG

What is PCR?-Polymerase Chain ReactionA way of producing large amounts of a gene to be studied

PCR Simulations

American Museum of Natural Historyhttp://www.amnh.org/learn/pd/genetics/pcr/

Howard Hughes Medical Institute: Bacterial ID Lab

http://www.biointeractive.org/vlabs/

cDNA is then used for these experiments.

It’s always a little more complicated than we make it seem…Remember that eukaryotic genes contain introns that need to be spliced out. Bacteria can’t splice mRNA, so…

•Scientists isolate the mature mRNA (introns taken out; exons put back together) and then add an enzyme called reverse transcriptase.•Reverse Transcriptase reads mRNA and makes DNA•This new DNA is called cDNA (“copy”)

DNA Fingerprinting(a.k.a. Electrophoresis)

1. Collect sample which contains DNA (white blood cells, skin cells, semen, vaginal swabs, hair follicles, etc.)

2. Add restriction enzymes that cut DNA (preferably at RFLPs)

3. Place DNA fragments on a bed of gel that has electrodes at either end.

4. Electrical current draws negatively charged fragments across the gel. (Shorter fragments travel further…)

5. Place nylon membrane on top of gel (sucks up fragments) and add radioactive probes (stick to fragments)

6. Place x-ray film on membrane. Develop.

+ Charge

- Charge

Electrophoresis Sites

DNA Fingerprint (Southern Blot) Tutorial

http://www.biology.arizona.edu/human_bio/problem_sets/DNA_forensics_1/01t.html

DNA Forensics Problem Set 1http://www.biology.arizona.edu/human_bio/problem_sets/DNA_forensics_1/DNA_forensics.html

DNA Forensics Problem Set 2

http://www.biology.arizona.edu/human_bio/problem_sets/DNA_forensics_2/DNA_forensics.html

NOVA: Create a DNA Fingerprint

http://www.pbs.org/wgbh/nova/sheppard/analyze.html