Genetic Engineering

What Is Genetic Engineering? Changing the DNA in living organisms to create something new.

Organisms, whose genes have been modified, are called Genetically Modified Organism (GMO) Example: Bacteria that produce human insulin, a hormone needed to treat diabetes. Genetically Modified organism are called transgenic organism; since genes are transferred from one organism to another.

1. artificial selection: breeders choose which organism to mate to produce offspring with desired traits. They cannot control what genes are passed. When they get offspring with the desired traits, they maintain them. Three types of artificial selection: A. selective breeding B. hybridization C. inbreeding

A. Selective breeding: when animals with desired characteristics are mated to produce offspring with those desired traits. Passing of important genes to next generation. Example: Champion race horses, cows with tender meat, large juicy oranges on a tree.

For example people breed dogs for specific purposes. Dachshund were once bred to hunt badgers and other burrowing animals. They must be small to fit into the animals hole in the ground.

Selective breeding occurs when you choose the best male and female to breed. This allows you to fine tune and control the traits The offspring or babies will then have the best traits. Then you continue to breed those organism with the best traits, those traits will be maintained.

Examples of selective breeding: Angus cows are bred to increase muscle mass so that we get more meat, Egg-Laying Hen-produces more eggs than the average hen

Selective Breeding

B. Hybridizations: two individuals with unlike characteristics are crossed to produce the best in both organisms. Example: Luther Burbank created a disease resistant potato called the Burbank potato. He crossed a disease resistant plant with one that had a large food producing capacity. Result: disease resistant plant that makes a lot of potatoes.

Other Examples of hybridization: Liger: lion and tiger mix

2. Grape + apple= grapple. The fruit tastes like grapes and looks like apple.

Hybridization Video

C. Inbreeding breeding of organism that genetically similar to maintain desired traits. Dogs breeds are kept pure this way. Its how a Doberman remains a Doberman. It keeps each breed unique from others. Risk: since both have the same genes, the chance that a baby will get a recessive genetic disorder is high. Inbreeding decreases variations. Risks: blindness, joint deformities.

Dolly: Dolly was the first mammal cloned. She had the same exact DNA as her mother and had no father. Cloning is a form of asexual reproduction. Only one genetic parent.

Since Dolly, cats and other organisms have been cloned. The cat that was cloned had the same exact DNA but different color fur than the mother. How can this be? Environment plays a huge part in the way organisms develop.

How Dolly Came to Be

2. Cloning: Type of asexual reproduction performed in a laboratory that produces identical individuals from a cell or from a cluster of cells taken from a multicellular organism. Clone: group of cells or organisms that are genetically identical as a result of asexual reproduction They will have the same exact DNA as the parent.

How is cloning done? A single cell is removed from a parent organism. An entire individual is grown from that cell. Remember one cell has all the DNA needed to make an entire organism. Each cell in the body has the same DNA, but cells vary because different genes are turned on in each cell.

Eggs are haploid Haploid: half the chromosomes, 23 in humans Body cells are diploid: Diploid: two sets of chromosomes, one from mom and one set from dad 46 in humans.

How could you clone a human? Step 1: An egg is removed from a female human Eggs are haploid: 23 chromosomes. The nucleus of the egg is removed and is thrown away. 23 EGG CELL

Step 2: A body cell is removed from another person. Body cells are diploid: 46 chromosomes. 46 Body Cell

The nucleus of the diploid body cell is put into the egg. Step 3: The nucleus of the diploid body cell is put into the egg. This egg no longer needs to be fertilized since it has all 46 chromosomes. 46 EGG CELL

Step 4: The egg is then charged with electricity to start mitosis. Step 5: Its then put into a surrogate mother so it can grow. Its going to be genetically identical to the parent of the body cell. But it will be a baby. Plants and animals can be cloned.

you can make exact copies of organisms with strong traits. Benefits of cloning: you can make exact copies of organisms with strong traits. Increase food supply Medical purposes: clone organs for transplants. Bring back or Stop species from going extinct. Saber Tooth Tiger extinct

Dog Cloning Example

Risks of cloning: Decreases genetic diversity If one of your clones gets a disease, they all get it: same immune system. Inefficient: high failure rate: 90%+ Expensive

3. Gene splicing: DNA is cut out of one organism and put into another organism A trait will be transferred from one organism to another. For example: the human insulin gene can be removed from a human cell. It can be put into a bacterial cell. The bacterial will now make human insulin.

Insulin Producing Bacteria,2:23

This picture represents gene splicing. However, DNA is much smaller. Its done with high tech lab equipment since DNA, is too small to hold or see without a microscope. The red piece the woman is holding is an insulin gene from a human being. It is being combined with DNA from a bacteria. Creates recombinant DNA, something that has never existed before.

Benefits: insulin is cheaper There are no side effects because it is human insulin. We once used pig insulin but there are side effects and it more expensive.

How are genes cut for gene splicing? A bacterial plasmid is used. Plasmid: circular DNA in a bacteria cell. It is very simple and easy to manipulate.

DNA Code: TTATGGCCATACGGCCTT AATACCGGTATGCCGGAA A restriction enzyme: enzyme that cuts the DNA at a specific code. There are thousands of restriction enzymes. Each cuts DNA at a different sequence. Some look for GGCC and cut in between the G and C. Every time GGCC is found in the DNA it is cut by the restriction enzyme DNA Code: TTATGGCCATACGGCCTT AATACCGGTATGCCGGAA

TTATGGCCATACGGCCTT AATACCGGTATGCCGGAA TTATGG CCATACGG CCTT AATACC GGTATGCC GGAA This DNA segment was cut twice creating three fragments. Since every one is different, we all have a different amount of times GGCC is found. My DNA may be cut seven times Yours may be cut ten times.

How is gene splicing done? 1. A restriction enzyme cuts the insulin gene out of the human DNA. 2. A plasmid is removed from a bacteria and cut with a restriction enzyme

3. The human gene is place into the bacteria plasmid 4. The plasmid is placed back into the bacteria. The cell now has directions (DNA) to make insulin. That's exactly what it does. Its human insulin, bacteria do not make insulin on their own. Plasmid with insulin gene

This is how a restriction enzyme works

This is called transformation: when a gene from one organism is transferred to different organism. The organisms that have DNA transferred to them are called transgenic organisms. trans: means different, genic: refers to genes Genetic engineering has given rise to a new technological field called biotechnology (technology of life).

1. Transgenic (GMO) animals: genes inserted into animals so they produce what humans need. Why?: A way to improve the food supply: A. Transgenic cows: gene inserted to increase milk production.

B. Spider goat: gene from spider inserted into goat. Goats makes silk of the spider web in their milk. Flexible, stronger than steel. Used in bullet proof jackets.

C. Glow-in-the-dark cats  Scientist used a virus to insert DNA from jellyfish The gene made the cat produce a fluorescent protein in its fur.  

2. Transgenic bacteria: gene inserted into bacteria so they produce things humans need. For example: insulin and clotting factors in blood are now made by bacteria.

3. Transgenic plants: plants are given genes so they meet human needs. A. Transgenic corn: given a gene so corn produces a natural pesticide. Now they don’t have to be sprayed with cancer causing pesticides. 25% of all corn is like this.

B. Venomous cabbage gene from a scorpion tails inserted into cabbage. Cabbage now produces that chemical. Why? Limit pesticide use while still preventing insects from damaging crops. Corporations state the toxin is modified so it isn’t harmful to humans.

C. Banana vaccines virus is injected into a banana, the virus DNA becomes part of the plant. As the plant grows, it produces the virus proteins — but not the disease part of the virus. When people eat a bite, their immune systems creates antibodies to fight the disease — just like a traditional vaccine Vaccines for hepatitis and cholera

A virus is often used to deliver DNA. In the movie “I Am Legend,” A healthy gene was inserted into a virus. The virus invaded the cancer cells and inserts the healthy gene to cure cancer. Worked at first but the virus mutated and became deadly. This is being attempted in real life.

Gene therapy: when disease causing genes are cut out and good gene are inserted. Restriction enzymes are used to cut out bad genes. Viruses are used to insert good genes. Not approved for human use yet. Some possible side effects.

4. Gel electrophoresis: a technique used to compare DNA from two or more organisms. Why compare DNA: Who committed a crime. How closely species are related.

How is electrophoresis done? A. The DNA is cut into fragments with a restriction enzyme. B. The cut DNA is then put into the wells of a machine filled with gel. The gel is spongy and the DNA squeezes through the pores.

C. The machine is plugged in and the fragments get separated based on their size. The smaller fragments move further than the large.

Electrophoresis results Separation of DNA based on size of fragments. Electrophoresis results Final result of electrophoresis

Electricity provides the energy Why does DNA move? DNA has a negative charge. When the machine is plugged it, its moves towards the positive pole created by the electricity

electrophoresis

Your DNA is so unique its considered to be a DNA fingerprint. Gel electrophoresis will separate your DNA differently from anyone else.