Genetic Engineering

• Genetic Engineers can alter the DNA code of living organisms.

• Selective Breeding

• Recombinant DNA

• PCR

• Gel Electrophoresis

• Transgenic Organisms

Changing the Living WorldSelective Breeding

• Humans use selective breeding, which takes advantage of naturally occurring genetic variation in plants, animals, and other organisms, to pass desired traits on to the next generation of organisms.

• All modern-day crops were cultivated by this method

as well as all breeds of dogs.

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Selective breeding transformed teosinte's few fruitcases (left) into modern corn's rows of exposed kernels (right).

Teosinte – ancestor of corn (Mexico)

• Cob selection• 5000BC – 2cm• 3000BC – 4cm• 1000AD – 13cm

Breeding and artificial selection

Variation in potatoes

Selective Breeding

• Breed only those plants or animals with desirable traits

• People have been using selective breeding for thousands of years with farm crops and domesticated animals.

The process by which desired traits of certain plants and animals are selected and passed on to their future generations is called selective breeding.

Selective Breeding

Genetics and Biotechnology

German shepherdService dog

HuskySled dog

Saint BernardRescue dog

Selective Breeding• Inbreeding is the continued breeding of individuals

with similar characteristics.

Inbreeding

• The controlled breeding of closely related organisms.

• Positive effects: controlled traits and characteristics. Pure bred dogs

• Negative effects: excessive inbreeding can produce unwanted effects because of lack of variation. Blindness in German shepherds

Inbreeding• Has risks due to the similarity of the genes between these two

organisms. • There is a higher risk of defective recessive alleles pairing up in

their offspring. • Ex. Blindness, deafness (white cats, dalmations)

hip dysplasia -(GoldenRetrievers)

•Hybridization – The crossing of dissimilar individuals to bring together the best of both organisms.

So if inbreeding reduces variation and

makes individuals very similar, how do

you increase variation?

Increasing variation

• Use radiation or chemicals• Can produce new strains of

bacteria and new plants.

Increasing Variation• Mutations can be induced

to help create variation in organisms.

• Polyploidy plants have an extra chromosome.

Polyploidy

• Having a multiple of the normal chromosome number.

• Example: regular chromosome number is 9. Polyploidy condition could be 18, 27, 36, etc.

More complex forms of genetic engineering include

gene splicing, transferring genetic material from one organism to

another

Recombinant DNA

Biotechnology

• A “new” field of biology that utilizes genetic engineering to produce new substances in the fields of health and industry.

Recombinant DNA• The manipulation and combination

of DNA from two sources • Bacterial DNA + human gene for

insulin

• http://player.discoveryeducation.com/?guidAssetId=166DED13-FCC3-4388-82B7-07ED4987DDE5

Recombinant DNA

• The ability to combine the DNA of one organism with the DNA of another organism.

• Recombinant DNA technology was first used in the 1970’s with bacteria.

Recombinant Bacteria1. Remove bacterial DNA (plasmid).

2. Cut the Bacterial DNA with “restriction enzymes”.

3. Cut the DNA from another organism with “restriction enzymes”.

4. Combine the cut pieces of DNA together with another enzyme and insert them into bacteria.

5. Reproduce the recombinant bacteria.

6. The foreign genes will be expressed in the bacteria.

Human Cell

Gene for human growth hormone

Sticky ends

Recombinant DNA

Gene for human growth hormone

DNA insertion

DNA recombination

Bacterial cell for containing gene for human growth hormone

Bacterial Cell

Plasmid

Bacterial chromosome

How recombination works

• Cut plasmid (circular piece of bacteria DNA that serves as a “host”) with restriction enzyme

• Cut gene of interest with restriction enzyme

• Splice together gene of interest and plasmid

Cutting DNA

• Usually use a restriction enzyme : a chemical used to cut out a specific segment of DNA.

Cutting and Pasting

• Use DNA synthesizers to make recombinant DNA (DNA from two different organisms spliced together)

Sneaking In

You probably have heard of computer viruses. Once inside a computer, these programs follow their original instructions and override instructions already in the host computer. Scientists use small “packages” of DNA to sneak a new gene into a cell, much as a computer virus sneaks into a computer.

1. Computer viruses enter a computer attached to some other file. What are some ways that a file can be added to a computer’s memory?A file can be downloaded from a CD or the Internet.

2. Why would a person download a virus program?The computer user would not willingly download a virus but would download a program that appeared to be useful.

3.If scientists want to get some DNA into a cell, such as a bacterial cell, to what sort of molecule might they attach the DNA?Possible answers: a useful protein or a strand of DNA that the cell would recognize and accept

Vocab

• Plasmid - circular DNA molecule found in bacteria• genetic marker - gene that makes it possible to

distinguish bacteria that carry a plasmid with foreign DNA from those that don’t

• Recombinant DNA – DNA that has been created artificially. DNA from two or more sources is incorporated into a single recombinant molecule.

Plasmids• A small circular

molecule of DNA1. It often has a DNA

sequence that serves as an origin of replication.

2. Contain genetic markers.

Vectors: is a DNA molecule used as a vehicle to transfer foreign genetic

material into another cell

• Plasmids• Viruses• bacteriophages

Characteristics of a Vector

• Can replicate independently in the host cell –

• Has restriction sites• Has a reporter gene “marker” that

will announce its presence in the host cell (Anti-biotic resistance, P-Glo)

• Is a small size in comparison to the host chromosome for ease of isolation

“Reporter gene”: Genetic marker.

pGlo

• Transformation of E. coli with the pGlo plasmid

• If the bacterium uptakes the plasmid it should glow in response to long range uv light

Transformation

• When a cell (usually a bacterium) takes in DNA from outside the cell and incorporates it into its own DNA.

• Example: Griffith’s rats

Cell Transformation

• During transformation, a cell takes in DNA from outside the cell. This external DNA becomes a component of the cell’s DNA.

• Transforming Bacteria

Plasmid – circular DNA molecule found in bacteria.

Why have plasmids been useful for DNA transfers?

1. It has a DNA sequence (gene) that helps promote plasmid replication. If the foreign DNA manages to get inside, it will get replicated (copied).

2. It has a genetic marker – a gene that makes it possible to distinguish whether it is carrying the foreign DNA. They usually use a gene that is resistant to antibiotics. The bacterial cell will not die when exposed to an antibiotic. When exposed, if it doesn’t die, you know the foreign DNA is inside.

Section 13-3

Human Cell

Gene for human growth hormone

Recombinant DNA

Gene for human growth hormone

Sticky ends

DNA recombination

DNA insertion

Bacterial Cell

Plasmid

Bacterial chromosome

Bacterial cell for containing gene for human growth hormone

Section 13-3

Figure 13-9 Making Recombinant DNA

Transforming Plants

Applications of Genetic Engineering1986 – Steven Howell created the glow in the dark tobacco

This proved the basic mechanism of how genes work was true for all living organisms.

A. Transgenic Organisms

Transgenic - a organism which contains genes from another species.

Genetic engineering has spurred the growth of biotechnology, which is a new

industry that is changing the way we interact with the living world.

Mice with jellyfish genes.

Only glow under

florescent lights. They

passed this gene to their

offspring. 2002

Seen in ordinary light, one such pig appears yellowish. Under ultraviolet light, the pigs glow green.

Recognition sequences

DNA sequence

Section 13-2

Restriction Enzymes

Recognition sequences

DNA sequence

Restriction enzyme EcoRI cuts the DNA into fragments. Sticky end

Section 13-2

Restriction Enzymes

Recombinant DNA in Industry

• E. coli has been modified to produce an indigo dye to color blue jeans

• Recombinant DNA has been used to help production of cheese, laundry detergent, paper production, sewage treatment– Increase enzyme activity, stability and

specificity

Benefits of Recombinant Bacteria

1. Bacteria can make human insulin or human growth hormone.

1. Bacteria can be engineered to “eat” oil spills.

Example of how Recombinant DNA helps humans:

Pharmaceuticals:• insulin for diabetics • factor VIII for males suffering from hemophilia A • factor IX for hemophilia B • human growth hormone (GH) • erythropoietin (EPO) for treating anemia • three types of interferons • several interleukins • granulocyte-macrophage colony-stimulating factor (GM-CSF) for stimulating the bone

marrow after a bone marrow transplant • tissue plasminogen activator (TPA) for dissolving blood clots • adenosine deaminase (ADA) for treating some forms of severe combined immunodeficiency

(SCID) • angiostatin and endostatin for trials as anti-cancer drugs • parathyroid hormone • leptin • hepatitis B surface antigen (HBsAg) to vaccinate against the hepatitis B virus

Golden Rice- Agriculture biotech

• Golden rice is the result of an effort to develop rice varieties that produce provitamin-A (beta-carotene) as a means of alleviating vitamin A (retinol) deficiencies in the diets of poor and disadvantaged people in developing countries. Because traditional rice varieties do not produce provitamin-A, transgenic technologies were required.

Recombinant DNA in Agriculture

• Crops that stay fresh longer and are more resistant to disease

• Plants resistant to herbicide so weeds can be killed easier

• Higher product yields or higher in vitamins• Peanuts and soybeans that don’t cause

allergic reactions

http://www.pbs.org/wgbh/nova/ancient/miracle-rice.html

NOVA miracle of rice

http://www.teachersdomain.org/resource/tdc02.sci.life.gen.btcorn/

Genetic engineered corn (5 minute video)

http://www.teachersdomain.org/resource/tdc02.sci.life.gen.breeding/

Classic breeding vs. genetic engineering video (3min)

Recombinant DNA in Medicine• Production of Human

Growth Hormone to treat pituitary dwarfism

• Insulin Production by bacterial plasmids

• Antibodies, hormones, vaccines, enzymes, and hopefully more in the future

Vaccines• Bananas have potential to

become the world's first edible vaccine due to Agrobacterium. An edible vaccine doesn't need sterile syringes, costly refrigeration, or multiple injections. According to the World Health Organization (WHO), more than 2 million children die worldwide each year from diarrhea that can be prevented easily with vaccines.

The DNA of plants and animals can also be altered.

PLANTS

1. disease-resistant and insect-resistant crops

2. Hardier fruit

3. 70-75% of food in supermarket is genetically modified.

How to Create a Genetically Modified Plant

1.Create recombinant bacteria with desired gene.

2. Allow the bacteria to “infect" the plant cells.

3. Desired gene is inserted into plant chromosomes.

What do you think about eating genetically modified foods?

pGlo – GfpGreen fluorescent protein

Green Fluorescent Protein and Plants

GFP and mice

Glo fish• Fluorescent zebra fish

were specially bred to help detect environmental pollutants. By adding a natural fluorescence gene to the fish, scientists are able to quickly and easily determine when our waterways are contaminated

pGlo• Transformation of E. coli

with the pGlo plasmid• Ori• Gene for Gfp• The plasmid contains the

genes for the Arabinose promoter

• The plasmid contains the genes for ampicillin resistance

• If the bacterium uptakes the plasmid it should glow in response to long range uv light

Ha Ha Ha!

Genetic Engineering and Crime Scenes……

What are we eating everyday?

Food Properties Percent modified inUnited States

Soybeans Resistant to herbicides

89%

Cotton Pest-resistant cotton

83%

Hawaiian papaya

Resistant to ringspotvirus

+50%

AquaAdvantage Salmon (created by AquaBounty), also known as “Frankenfish,”

http://www.youtube.com/watch?v=SDI1j2YR6Oo

http://www.teachersdomain.org/resource/tdc02.sci.life.gen.salmon/

Aquabounty fish

http://www.marklynas.org/2013/01/lecture-to-oxford-farming-conference-3-january-2013/

Environmentalist’s apology for talking negative about GM foods 51:52

• first 6 minutes

DNA Extraction

• Where is the DNA located in a cell?

• -the nucleus• First must break apart

the cell membrane and nucleus to get at the DNA

Manipulating DNA• Genetic Engineering is

the process of reading and changing DNA sequences in an organism.

• Reading the Genetic Code– DNA extraction– Cutting and Labeling DNA– Separating DNA– Reading the DNA

sequence– Making Copies (PCR –

polymerase chain reaction)

Manipulating DNA• Genetic Engineering is

the process of reading and changing DNA sequences in an organism.

• Reading the Genetic Code– DNA extraction– Cutting and Labeling

DNA– Separating DNA– Reading the DNA

sequence– Making Copies (PCR –

polymerase chain reaction)

Manipulating DNA• Genetic Engineering is

the process of reading and changing DNA sequences in an organism.

• Reading the Genetic Code– DNA extraction– Cutting and Labeling

DNA– Separating DNA– Reading the DNA

sequence– Making Copies (PCR –

polymerase chain reaction)

Manipulating DNA• Genetic Engineering is

the process of reading and changing DNA sequences in an organism.

• Reading the Genetic Code– DNA extraction– Cutting and Labeling DNA– Separating DNA– Reading the DNA

sequence– Making Copies (PCR –

polymerase chain reaction)

Gel Electrophoresis

gslc

• http://www.dnalc.org/resources/animations/gelelectrophoresis.html

DNA Fingerprinting

Gel Electrophoresis• Placing a mixture of

DNA into a gel and applying an electric current. DNA is then separated according to size.

Gel Electrophoresis

• This technology allows scientists to identify someone’s DNA!

Steps Involved in Gel Electrophoresis

1. “Cut” DNA sample with restriction enzymes.

2. Run the DNA fragments through a gel.

3. Bands will form in the gel.

4. Everyone’s DNA bands are unique and can be used to identify a person.

5. DNA bands are like “genetic fingerprints”.

Perform your own Gel Electrophoresis

• Go to this website to perform your gel electrophoresis

• http://gslc.genetics.utah.edu/units/biotech/gel/• Once you understand the process, use your DNA

detective skills to help solve a mystery.• http://

www.pbs.org/wgbh/nova/sheppard/analyze.html• Or google NOVA DNA Fingerprint

– NOVA Online | Killer's Trail | Create a DNA Fingerprint

Uses of Gel Electrophoresis• DNA Fingerprinting

– An individual's DNA is as distinctive as a fingerprint. DNA samples can be obtained from the trace amounts of blood or sperm. These DNA samples can be separated using gel electrophoresis. The number and position of bands formed on each lane of gel is the actual genetic "fingerprint" of that DNA sample. The characteristics of certain segments of DNA vary from person to person and form a highly individual, detectable "genetic fingerprint." Developed only in the mid-1980s, genetic fingerprinting has rapidly become a widely used courtroom tool. In 1988 the first person in the United States was executed based on DNA technology.

• The Human Genome Project– The most ambitious research project made possible by DNA

technology is the effort to map the entire human genome.

Genetic Engineering

Polymerase Chain ReactionPCR

• PCR allows scientists to make many copies of a piece of DNA.

1. Heat the DNA so it “unzips”.

2. Add the complementary nitrogenous bases.

3. Allow DNA to cool so the complementary strands can “zip” together.

PCR – Polymerase Chain Reaction• Making copies to work with.

Twins brothers, different parents after test tube mix-up Wilma and Willem Stuart were a Dutch couple who had been unsuccessfully trying to conceive for years and decided to try IVF. They soon learned they would be parents of twins. When the two boys were born, Koen had blue eyes, dark hair and pink skin, Tuen had dark eyes dark hair and brown skin. A DNA test revealed that Koen was the Stuarts child but Tuen was not Willem’s. The report of the investigation has not been made public, but speculation is that a piece of lab equipment called a pipette, like a large eyedropper, had been used twice, causing another man’s sperm to be mixed with Willem’s. The hospital called it a “deeply regrettable mistake”. The Stuarts remembered there was a black couple in the waiting room the same day during the IVF process. The hospital located the man and confirmed he was Tuen’s biological father. Although he was under no obligation to meet his son he never knew he had, he did when Koen was 18 months old. The biological father only looked at him from a distance and didn’t try to claim him and was comfortable that the Stuarts loved the child, and let them continue raising him.

Transgenic organisms

• When an organism contains genes from other organisms.

• Example:– A tobacco plant

that contained DNA from a firefly.

Genetically modified organisms are called transgenic organisms.

TRANSGENIC ANIMALS

1. Mice – used to study human immune system

2. Chickens – more resistant to infections

3. Cows – increase milk supply and leaner meat

4. Goats, sheep and pigs – produce

human proteins in their milk

Transgenic Animals

• A transgenic sheep was produced that contained the corrected human gene for hemophilia

• This human gene inserted into the sheep produces the clotting protein in the sheep’s milk– This protein can then be given to hemophilia

patients

Human DNA in a Goat Cell

This goat contains a human gene that codes for a blood clotting agent. The blood clotting agent can be harvested in the goat’s milk.

.

Transgenic Goat

Desired DNA is added to an egg cell.

How to Create a Transgenic Animal

Transgenic animals

• Livestock can grow faster, better quality of meat, resistant to disease.

• Cows that produce human proteins in their milk.

Transgenic plants

• Usually cash crops such as cotton, corn, wheat, soybeans, etc.

• Often incorporates bacterial DNA to make the crop resistant to disease, pests, or chemicals.

• Ex: Bt corn

Transgenic mice

• Two baby mice - same age• Human Growth hormone

inserted into the embryo of the mouse on the left. Causes rapid growth in the newborn

• The mouse on the right is a normal sized mouse

1. Transgenic animals are often used in research. What might be the benefit to medical research of a mouse whose immune system is genetically altered to mimic some aspect of the human immune system? Students may say that a mouse with a humanlike immune system would be a good laboratory model for immune research.

2. Transgenic plants and animals may have increased value as food sources. What might happen to native species if transgenic animals or plants were released into the wild?Transgenic organisms might disrupt normal balances in ecosystems and could breed with natural populations, changing them.

Cloning

• Clone: a member of a population of genetically identical cells produced from a single cell.

• 1997: first mammal cloned. Dolly, the sheep.

How do you make a clone?

Cloning Animals• Dolly was the first animal cloned in 1997• Since then, goats, mice, cattle, pigs, etc.

have been cloned• Take DNA out of embryonic stem cells or

zygote and insert new DNA

Is cloning a good thing or a bad thing?

• Cloning articles

• On December 27, 2002, the Raelians, an unusual religious sect, claimed that the first cloned human baby had been born. New reports were published by CNN, BBC, ABC, and most major media. Most scientists (including authors Ken Miller and Joe Levine) now believe that these reports were nothing more than an elaborate hoax.

Gene therapy

http://player.discoveryeducation.com/?guidAssetId=7D2E6BA0-53A6-448B-A559-ED58D9E3E1AB

http://player.discoveryeducation.com/?guidAssetId=B76C7495-F4F0-4CB4-926E-BFD46A3060A8

Gene pool: the sum total of all the heritable genes in a given population

Forces that Change Gene Frequencies

1. Migration can change the gene frequency of a population if the migrants have a different gene frequency than that of the population they are leaving or entering.

Example

During a bottleneck, a large population undergoes a decrease in size so that relatively few individuals remain. Because there are few individuals, the gene frequency is more likely to drift.

http://www.pbs.org/wgbh/nova/body/cracking-your-genetic-code.html

53:27

Cracking Your Genetic CodeWe are on the brink of a new era of personalized, gene-based medicine. Are we ready for it? Airing March 28, 2012 at 9 pm on PBS Aired March 28, 2012 on PBS

What will it mean when most of us can afford to have the information in our DNA—all six billion chemical letters of it—read, stored and available for analysis? "Cracking Your Genetic Code" reveals that we stand on the verge of such a revolution. Meet a cancer patient who appears to have cheated death and a cystic fibrosis sufferer breathing easily because scientists have been able to pinpoint and neutralize the genetic abnormalities underlying their conditions. But what are the moral dilemmas raised by this new technology? Will it help or hurt us to know the diseases that may lie in our future? What if such information falls into the hands of insurance companies, employers or prospective mates? One thing is for certain: the new era of personalized, gene-based medicine is relevant to everyone, and soon you will be choosing whether to join the ranks of the DNA generation.

http://www.npr.org/blogs/health/2012/12/03/165272373/genome-sequencing-for-babies-brings-knowledge-and-conflicts?sc=17&f=1001

Genome sequencing for babies . NPR listen to the story 00:08:08