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Aim: How does selective breeding affect genetic variation?
Do Now: DNA Regents Questions HW #1: Selective Breeding
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Meet the Super Cow 1. Describe the cow in the video clip.
2. What procedure produced this cow? 3. Describe the process of selective breeding.
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Engineer a Crop: Selective Breeding http://www. pbs
In the past, farmers saved their best seeds and planted them the following growing season. By doing so, the next season’s crops would be slightly bigger, or sweeter, or more resistant to disease. The change was slight, but over many generations, crops did change significantly. Hypothesize: If you keep selecting the seed from the biggest ear of corn, what should happen to the overall size of the corn as you move through each growing season?
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Selective Breeding Use natural reproduction to obtain desired characteristics Select for desirable traits in offspring by choosing organisms of the same species to mate
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Real Life Examples of Selective Breeding
Dairy farmers may choose to mate only cows that give the most milk Seedless Fruit Purebred Animals Wild Mustard Plant Hypoallergenic Cat
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Real Example of Selective Breeding
Hybrid = + Horse Donkey Mule Big, Fast, Excitable Small, Slow, Calm Strong, Endurance, Calm
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Real Example of Selective Breeding
In 1872, Luther Burbank developed a new potato. While trying to improve the Irish potato, Burbank developed a hybrid that was disease resistant. He introduced the Burbank potato to Ireland to help combat the potato famine. Disease Resistant Potato Disease resistant potato + Food-producing potato Burbank hybrid
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Advantages: Desirable traits Resistance to disease Seedless fruit Bigger crops Disadvantages: Decreases variation Recessive genetic disorders increase Ex. Hip dysplasia in certain dog breeds.
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Aim: How can DNA be Used to Create Genetically Identical Individuals?
Do Now: Selective Breeding Do Now HW #2: Cloning 10
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Cloning and the Tasmanian Tiger
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Clone An organism that is genetically identical to the organism from which it was produced. Asexual Reproduction 12
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Animals that Have Been Cloned
Sheep (Dolly) Cat (Beaker) Frog Salamander Mouse Hello Dolly!! 13
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How is Cloning Done? The nucleus of a body cell from the desired organism is removed. An egg cell from an adult female sheep is removed. (The nucleus of the egg cell is removed) The nucleus and egg cell are joined using an electric shock to form an embryo 4. The dividing embryo is placed inside a surrogate mother and the pregnancy begins. 5. Birth of clone Who will the clone be genetically identical to: nucleus donor egg cell donor surrogate mother 15
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Reasons to Clone Organisms
Revive endangered or extinct species 2) Reproduce a deceased pet 3) Cloning livestock 4) Drug Production 4) Cloning in medicine Cloning animal models of disease Cloning to make stem cells 16
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Reasons NOT to Clone Success rate in cloning is quite low
Ethical/Moral issues – “playing God” Legal issues - how should cloning technologies be regulated Social issues – impact of cloning technologies on society as a whole.
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Cloning Summary ?
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What color will the baby be? Why?
Body Cell (Nucleus) Donor Egg Cell Donor Surrogate Mother Cloned offspring – where the nucleus comes from determines the color 19
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Scientists have cloned sheep but have not yet cloned a human
Scientists have cloned sheep but have not yet cloned a human. The best explanation for this situation is that the technology to clone humans has not been explored human reproduction is very different from that of other mammals there are many ethical problems involved in cloning humans cloning humans would take too long
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The diagram below represents the process used in 1996 to clone the first mammal, a sheep named Dolly. Which statement concerning Dolly is correct? 1. Gametes from sheep A and sheep B were united to produce Dolly. 2. The chromosome makeup of Dolly is identical to that of sheep A. 3. Both Dolly and sheep C have identical DNA. 4. Dolly contains genes from sheep B and sheep C.
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Modern technology could be used to clone pet dogs and cats
Modern technology could be used to clone pet dogs and cats. The cloned animals would resemble the original pets because 1. the genes of the new animals are different from those of the original pets 2. half of the genetic information of the new animals is the same as that of the original pets 3. the new animals have mutations not found in the original pets 4. the new animals have the same genetic information as the original pets
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Cloning Animals – Recipe for Resurrection http://ngm
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Aim: How can a gene be altered?
Do Now: Regents Review Questions HW# 3: Genetic Engineering 25
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Gene – DNA Base Sequence
Review - Genes Gene – DNA Base Sequence Protein Trait The genetic base sequence codes for proteins, which determine our traits. 26
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What Is a Genetically Modified Food. http://www. scientificamerican
Genetically modified foods have been demonized in recent years by health advocates and environmentalists alike. If we look at the history of food cultivation, however, it is apparent we've been eating them all along. SA editor Eric R. Olson explains.
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The Genetic Code is Universal!
All living organisms… use the same DNA use the same code book read their genes the same way (protein synthesis in the ribosomes) Strong evidence for a single origin in evolutionary theory! Strong evidence for a single origin in evolutionary theory. 28
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Process used to alter the genetic code of an organism
Genetic Engineering Process used to alter the genetic code of an organism Glowing Green Protein ANDi Science 360: Designer Foods Science 360: Genetic Engineering (Insulin) 29
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Why do Scientists Genetically Engineer Organisms?
Medical Reasons It allows organisms to produce new proteins beneficial for humans human insulin human growth hormone (HGH) 30
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How is Genetic Engineering Accomplished?
Identify gene Using an enzyme, cut DNA in both organisms Using the enzyme, insert new gene into organism Organism reads gene as if it were its own Organism produces NEW protein NEW TRAIT New inserted gene causes the organism to produce a new protein (ex: insulin, HGH) 31
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Restriction Enzymes Scissor-like enzymes that cut DNA at specific base sequence sites Restriction enzymes used by bacteria to cut up DNA of attacking viruses Ex. EcoRI, HindIII, BamHI Cut creates “sticky end” 32
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Real Life Uses of Genetic Engineering
Genetically modified organisms (GMO) enables organisms to produce new proteins Protect crops from insects: BT corn corn produces a toxin that kills corn caterpillar Extend growing season: fishberries strawberries contain an anti-freezing gene from flounder Improve quality of food: golden rice rice producing vitamin A improves nutritional value Bt Corn: Super Salmon: Article: 33
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Summary: The Process of Genetic Engineering
1. gene from human cut with enzyme + 4. recombinant DNA is inserted into a bacteria 3. recombinant DNA 2. Bacterial plasmid cut with enzyme 5. Bacteria reproduce (asexual) 6. Extract protein 34
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1. What process is represented by the diagram above?
2. What is used to “cut” and “glue” the DNA? 3. Name a specific substance that can be produced by genetic engineering and explain how it is beneficial to humans. 4. What type of reproduction is represented by A? 35
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Aim: How are DNA Fingerprints Used to Identify People?
Do Now: DNA Regents Questions HW #4: Gel Electrophoresis Biotechnology Test Thursday 36
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What Role does DNA Evidence Play in Solving Crimes?
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Gel Electrophoresis Technique used to separate DNA based on size using an electrical field Uses of Gel Electrophoresis Forensics Medical diagnostics Paternity Evolutionary relationships 38
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Where do Scientists Find DNA to Compare?
Trace amounts of DNA are found in the following samples: Blood Tissue Semen Urine Hair Teeth Saliva Bone
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Polymerase Chain Reaction (PCR)
Developed by Kary Mullis in 1983 DNA Amplification - Used to produce large amounts of DNA from trace amounts of DNA BioRad PCR Video: BioRad GTAC Video: PCR Virtual Lab:
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“swimming through gel”
Gel Electrophoresis DNA moves in an electrical field Why? DNA is Negatively charged Being negatively charged, DNA moves towards the positive side The SIZE of a DNA fragment affects how far it travels Small pieces are Swift and travel farther Large pieces travel slower & Lag behind DNA – + Large Small “swimming through gel” 41
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The Steps - Gel Electrophoresis
DNA is cut with specific restriction enzymes into different sized fragments. DNA fragments are loaded into wells of the gel. Electric current is passed through the gel making one side + charged and one side – charged. Gel Electrophoresis – CS Harbor Simulation: 42
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The Steps - Gel Electrophoresis
DNA is negatively charged and moves through the gel to the positive side. This electric current causes DNA to separate based on size. Smaller segments move faster than the larger segments and appear as bands Consider this analogy. Imagine that all the desks and chairs in the classroom have been randomly pushed together. An individual student can wind his/her way through the maze quickly and with little difficulty, whereas a string of four students would require more time and have difficulty working their way through the maze. 43
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Analyzing Gel Electrophoresis
Ex. Forensics suspects crime scene sample S1 S2 S3 V – DNA + Alan Newton Interview – The Innocence Project 44
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Analyzing Gel Electrophoresis
Ex. Paternity Results
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