- Slides: 54
• Genetic engineering: Changing the DNA in living organisms to create something new. • This organisms are called Genetically Modified Organism (GMO) • Example: • Bacteria that produce human insulin • Genetically Modified organism are called transgenic organism; since genes are transferred from one organism to another.
Some genetic engineering techniques are as follows: 1. Artificial selection A. selective breeding B. hybridization C. inbreeding 2. Cloning 3. Gene splicing 4. Gel electrophoresis: analyzing DNA
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 Henproduces more eggs than the average hen
• 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: 1. Liger: lion and tiger mix
2. Grape + apple= grapple. The fruit tastes like grapes and looks like apple.
C. Inbreeding 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. • Risks: blindness, joint deformities.
• Variation: difference between individuals of a species. • The differences are in the genes but we see the physical differences. • For example: Some humans have blond hair and some have brown. This is a variation among humans. • Some finches have short beaks, some have long beaks. • Inbreeding decreases variations.
2. Cloning: creating an organism that is an exact genetic copy of another. • There are human clones in our school. • identical twins are naturally created clones. • 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.
• • 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. http: //content. tutorvista. com/biology_11/content/media/cloning. swf
• 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.
• 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. • The nucleus of the body cell is removed • Body cells are diploid: 46 chromosomes. 46 Body Cell
• 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.
Click and clone • http: //learn. genetics. utah. edu/content/tech/cloni ng/clickandclone/
Benefits of cloning: 1. you can make exact copies of organisms with strong traits. 2. Increase food supply 3. Medical purposes: clone organs for transplants. 4. Bring back or Stop species from going extinct. Saber Tooth Tiger extinct
Risks of cloning: 1. Decreases genetic diversity 2. If one of your clones gets a disease, they all get it: same immune system. 3. Inefficient: high failure rate: 90%+ 4. Expensive
3. Gene splicing: DNA is cut 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.
• 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.
• 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.
This is how a restriction enzyme works
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 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: 1. Find your baby’s daddy 2. Who committed a crime. 3. 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.
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
Your DNA is so unique its considered to be a DNA fingerprint. Gel electrophoresis will separate your DNA differently from anyone else. Nova: who done it http: //www. pbs. org/wgbh/nova/sheppard/analyze. html http: //www. teachersdomain. org/asset/tdc 02_i nt_creatednafp 2/
• • Genetic engineering creates organisms with recombinant DNA. Recombinant DNA: when DNA is combined from at least two organisms. Which techniques create recombinant DNA 1. Sexual reproduction: natural 2. selective breeding 3. Hybridization 4. Gene splicing
• Does cloning create organisms with recombinant DNA? • No, the DNA from one organism is copied. • DNA is not recombined.