Biotechnology!

Can you imagine?

• A monkey that glows in the dark?• A fish that glows when exposed to

environmental pollutants?• An edible vaccine, like a banana, instead of a

needle for immunizations?• Pork that is as healthy as fish?• A cow that produces human growth hormone in

her milk? • Tobacco plants with firefly genes so that they

glow?

Well, imagine no more!

• All of these are possible thanks to genetic engineering, manipulating the genes of an organism for practical purposes

• First developed in 1973 by Cohen & Boyer – took frog DNA & inserted it into the DNA of a bacterium (Escherichia coli)

• We have come a long way in the 20+ years since then….

Genetic Engineering!● Involves building recombinant DNA (rDNA)

●Joining together of DNA from 2 or more different organisms

● Can be used to produce insulin, growth hormone, oxytocin, interferons, etc.

● Opened up a whole new type of “pharming” – organisms who produced essential proteins in their milk!

● Much more…

How is rDNA produced?

• Step 1 – cut DNA using restriction enzymes (both the gene of interest & the DNA from a vector) A vector is an organism used to carry the gene, (commonly includes viruses, yeast, and bacterial plasmids.) Plasmids are circular rings of DNA found in bacteria.

Step 2

• Combine/splice the DNA from the 2 different organisms (an enzyme called ligase seals the DNA fragments together)

Holt, Rinehart and Winston: Science Online Editions

Step 3

• The bacteria then reproduce via binary fission and the gene inserted is cloned, making many copies of the gene of interest.

Step 4

• The cells then transcribe and translate the gene making the desired protein coded for by the gene that was spliced in!

Overall process

Transgenic Animals

Applications in Medicine• Pharmaceutical companies – produce medically important

proteins using rDNA in bacteria (factor VIII, insulin, etc)• Vaccines – using rDNA technology we are able to make

safer & more effective vaccines – Removing the pathogen’s (disease-causing) gene for surface

proteins and inserting it into a harmless bacteria or virus…then the vector will make that surface protein and the body will respond by producing antibodies

– Herpes, Hepatitis B,

hopefully malaria….

Applications in Medicine

• “Pharming” - introducing human genes into farm animals & they produce human proteins in their milk (proteins that are too complex for bacteria to make for us)– Nancy, Ethel & Herman – TRANSGENIC

organisms (have foreign DNA in their cells) that produce proteins in their milk

Applications in Agriculture

• Crops may be genetically engineered to be pest-resistant, improve nutritional content, improve yields, etc.

• GMO or “frankenfoods” include soybean, corn, tomatoes, etc. – make up a large % of crops in America

• First transgenic animals may end up on the dinner table soon!

• http://www.youtube.com/watch?v=FTfuAbzAeB8

Good

● Improved Medicines • Improved Livestock (resistance to disease) • Improved Crops (resistance to disease, higher

yields) • Prevention of Genetic Diseases • Lowering the cost of medicines (i.e. Insulin) • Safer Medicines (i.e. Insulin) • Treatment for pre-existing conditions (i.e.

Cancer)

Bad

• Safety concerns (viruses developing antibiotic resistance)

• Environmental concerns (“superweeds”) • Ethical dilemmas over human treatment (i.e. are

we playing God?) • Potential for experimental abuse (doctors using

patients as test subjects) • Treatment going from treating diseases to a

method for picking the traits you want in a child (i.e. specifying hair and eye color)

CLONING!

What is wrong (scientifically) with this cartoon?

Cloning!• Produces genetic replica

(Note: may not be identical – different env’t)

• Embryo vs. adult

• Cloning from an adult – trickier b/c cells are differentiated or specialized - first accomplished in 1997 by Ian Wilmut – Dolly the sheep was cloned from a 6 year old ewe – also called Somatic Cell Nuclear Transfer

Dolly the Sheep

• Unfortunately, Dolly had to be euthanized at 6 years of age due to what appears to be premature aging (vs. 12years)

Somatic Cell Nuclear Transfer

1. Remove somatic (body) cell from organism you want to clone.

2. Take an egg cell from donor and remove the nucleus (discard it)

3. Transfer the nucleus from the somatic cell into the enucleated egg cell.

4. Add chemical to stimulate cell division.

5. Implant into surrogate and wait for gestational period to deliver the clone!

$155,000 for a Cloned Dog???• http://www.youtube.com/watch?

v=wtPKcnsrsRQ

• http://www.youtube.com/watch?v=e1VL4XiC9nM

Let’s watch a movie!

Webquest time !!!Cloning in Focus

DIRECTIONS:

1. Please get a laptop & go to the URL above (It is also in your notes!).

2. GO TO LEARN GENETICS and cloning is on the bottom right side….

3. Please remember to take notes as you go and answer any and all questions posed.

4. The “Click and Clone” part is especially important because it highlights the steps involved.

DNA Fingerprinting!• Pattern of bands resulting from an individual’s

DNA fragments being separated by a process known as gel electrophoresis:

• (separates fragments based on electrical charge and size – the smaller the fragment, the farther it travels and the larger the fragment, the less it travels)

• Each individual has a unique “bar code”• Can be used to determine paternity, it is also

useful in forensics, also for identifying genes that cause genetic disorders

• DNA can be obtained from blood, saliva, skin, hair, bone, etc.

EXAMPLE!!! • A family consists of a mom and dad, two

daughters and two sons. The parents have one daughter and one son together, one daughter is from the mother’s previous marriage, and one son is adopted, sharing no genetic material with either parent. After amplifying the VNTR DNA from each member of the family, it is cut with a restriction enzyme and run on an agarose gel. Here are the results:

Simluated DNA Fingerprint

DNA Evidence

Webquest!

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

Let’s go try a DNA fingerprint!

Gene Therapy!

• Involves putting a healthy copy of a gene into a person who has a defective copy

• DNA can injected directly into tissue or can be delivered via a vector (such as a virus)

• First trials done in 1990 – individual with SCID

• Being used in trials for cystic fibrosis, cancer, hemophilia, etc.

Let’s Watch…

Human Genome Project!

• Project that began in 1990 – 2 goals in mind

1. determine the nucleotide sequence of the human genome (3 billion pairs!)

2. map the location of every gene

Will lead to improved medicines, diagnoses, treatments, and potentially cures for 4,000+ human genetic disorders!

Genome cartoon!!!

SOL QUESTIONS!!!

• The diagram shows DNA fingerprints from a daughter horse, the mother

• horse, and four possible fathers. Which horse is most likely the father?

• F 1

• G 2

• H 3

• J 4

And another one!

Scientists are using genetic engineering to develop a wheat crop that is resistant to a particular kind of moth. How would they determine if the plants are moth-resistant?

A Determine the length of the moth reproductive cycle in normal wheat.

B Determine whether moths in test wheat can be controlled with chemical sprays.

C Monitor numbers of moth species infesting normal wheat.

D Monitor moth populations in fields planted with test and normal wheat.

The End!