Understandings, Applications and Skills (This is what you maybe assessed on)

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1 3. Genetics 3.5 Genetic modification and biotechnology Name: Understandings, Applications and Skills (This is what you maybe assessed on) Statement Guidance 3.5.U1 3.5.U2 3.5.U3 Gel electrophoresis is used to separate proteins or fragments of DNA according to size. PCR can be used to amplify small amounts of DNA. DNA profiling involves comparison of DNA. 3.5.U4 3.5.U5 3.5.U6 3.5.U7 3.5.U8 3.5.A1 3.5.A2 3.5.A3 3.5.A4 3.5.S1 Genetic modification is carried out by gene transfer between species. Clones are groups of genetically identical organisms, derived from a single original parent cell. Many plant species and some animal species have natural methods of cloning. Animals can be cloned at the embryo stage by breaking up the embryo into more than one group of cells. Methods have been developed for cloning adult animals using differentiated cells. Use of DNA profiling in paternity and forensic investigations. Gene transfer to bacteria using plasmids makes use of restriction endonucleases and DNA ligase. Assessment of the potential risks and benefits associated with genetic modification of crops. Production of cloned embryos produced by somatic-cell nuclear transfer. Design of an experiment to assess one factor affecting the rooting of stem-cuttings.* Dolly can be used as an example of somatic-cell transfer. A plant species should be chosen for rooting experiments that forms roots readily in water or a solid medium. 3.5.S2 Analysis of examples of DNA profiles. Students should be able to deduce whether or not a man could be the father of a child from the pattern of bands on a DNA profile. 3.5.S3 Analysis of data on risks to monarch butterflies of Bt crops. *This is skill is best covered by a separate activity Recommended resources: 35-genetic-modification-and-biotechnology.html Allott, Andrew. Biology: Course Companion. S.l.: Oxford UP, Print.

2 3.5.U2 PCR can be used to amplify small amounts of DNA. 1. The polymerase chain reaction (PCR) is used where DNA samples are too small to be useful. a. State the purpose of PCR in labs and investigations. b. Identify the cellular process which PCR mimics. c. State the role of high temperatures in PCR. d. State the role of complementary base pairing in PCR. e. Describe why it is called a chain reaction. 3.5.U1 Gel electrophoresis is used to separate proteins or fragments of DNA according to size. AND 3.5.U3 DNA profiling involves comparison of DNA. 2. State two main uses of DNA profiling by electrophoresis. 3. State some other names for DNA profiling. 4. State the roles of the following components of gel electrophoresis: Component Role Restriction enzymes Gel Electric current Fluorescent DNA markers

3 5. Annotate the image below to outline briefly how gel electrophoresis works, including how the size of fragments affects their position on the final gel. 3.5.A1 Use of DNA profiling in paternity and forensic investigations. 6. Outline why DNA profiling is useful in forensic investigations. 7. DNA profiling can exclude certain candidates and give evidence to suggest the most likely father, or mother, of a child. List the circumstances in which DNA profiling is useful to a paternity investigation: 3.5.S2 Analysis of examples of DNA profiles. 8. Use the gel electrophoresis results below to answer these questions. In this case, a DNA sample was taken from a cigarette found at a crime scene (smoking in a no-smoking zone): a. State the process used to amplify the small amounts of DNA collected at the crime scene to an amount big enough to be used in DNA profiling.

4 b. Deduce which criminal, Rob McCarr or Nick Allott, left their dribbly cigarette-end at the crime scene. Explain your answer. Criminal: Explanation: c. Draw bands to show where the standard fragments would be observed. State the role of the standard fragment. d. Outline the evidence in the DNA profile that suggests Nick and Rob are related. 3.5.U4 Genetic modification is carried out by gene transfer between species. AND 3.5.A2 Gene transfer to bacteria using plasmids makes use of restriction endonucleases and DNA ligase. 9. Genetically modified organisms (GMOs) are created using gene transfer. a. Outline gene transfer. b. Explain how the universality of the genetic code is central to gene transfer applications. c. Define transgenic organism.

5 d. State the role of the following in gene transfer: i. Restriction enzymes ii. E. coli plasmids iii. Ligase iv. Vector e. Annotate the diagram below to outline the process of gene transfer:

6 f. Give four examples of genetically modified (GM) organisms and the effects of their new genes. Genetically modified organism New property Advantages Golden Rice Salt tolerant tomato plants Goats producing milk containing spider silk protein Human insulin producing bacteria 3.5.A3 Assessment of the potential risks and benefits associated with genetic modification of crops. AND Nature of science: assessing risks associated with scientific research - scientists attempt to assess the risks associated with genetically modified crops or livestock. (4.8) AND 3.5.S3 Analysis of data on risks to monarch butterflies of Bt crops. 10. Bt corn is an example of the genetic modification of crop. Bacillus thuringiensis (Bt) is a soil bacterium that produces insecticidal toxins. Genes from Bt have been inserted into maize so GM plants can produce an insecticidal toxin and therefore be resistant to pests, e.g. European Corn Borer. a. Identify which potential benefits apply when assessing the usefulness of Bt corn and outline how the introduced trait is a benefit. Potential benefit Applicable to Bt Corn? If so outline the benefit

7 b. Assess the risks of using Bt corn by evaluate the evidence for each of the potential risks. potential risk Evidence and evaluation Could be toxic to or cause allergic reactions in humans Transferred genes could mutate after testing Non-target organisms affected by toxins Increases resistance to toxin evolves in pests Accidental release may result in competition with native plant species Super weeds - through crossbreeding the introduced gene could be transferred to wild varieties Biodiversity reduced both plant populations by direct competition and animal populations directly and indirectly could be affected c. Patent laws prevent farmers producing locally suitable varieties. Which reduces the usefulness of GM crops. Explain why this is done. 11. The ecological impact of Bt corn upon monarch butterflies has been studied by scientists. a. Explain why monarch butterflies could be at risk from Bt corn.

8 The bar chart (left) shows survival of second to third-instar monarch larvae in a lab study. Three milkweed leaf treatments were conducted: leaves with no pollen (lavender), leaves treated with untransformed corn pollen (blue), and leaves dusted with pollen from Bt corn (black). The mean survival rate is based on the proportion of larvae surviving in five replicates of each treatment (from Losey, H. E., L. S. Rayor, and M. E. Carter Transgenic pollen harms monarch larvae. Nature 399: 214, 1999 Nature Publishing Group n.b. the error bars represent the standard error from the mean, i.e. the range within which the true mean is likely to be found. The graphs (right) give the findings from field studies. They show Survival curves for monarch larvae placed in and near Bt and non-bt corn fields. Survival curve (a) is based on data from Iowa and survival curve (b) is based on data from New York (from Stanley- Horn, D. E. et al Assessing the impact of Cry1Ab- expressing corn pollen on monarch butterfly larvae in field studies. Proceedings of the National Academy of Sciences 98: , 2001 National Academy of Sciences, U.S.A.). b. Explain why untransformed corn was included in the studies. To act as a control eliminate major biotic (predation) and abiotic (weather) impacts and natural mortality. c. Describe the trends seen in the lab study. d. Discuss whether there is evidence of Bt corn pollen affecting Monarch caterpillar survival. Are the error bars useful to the discussion?

9 e. Describe the trends seen in the field studies. f. Suggest reasons why Monarch catepillars Bt toxicity is easier to detect in laboratory studies. Rain/Wind/etc washes away corn pollen; Dosage/pollen exposure levels variable/lower in the field; Other acceptable suggestions; g. Evaluate the hypothesis that Bt Corn adversely affects Monarch butterfly populations. 3.5.U5 Clones are groups of genetically identical organisms, derived from a single original parent cell. AND 3.5.U6 Many plant species and some animal species have natural methods of cloning. AND 3.5.U7 Animals can be cloned at the embryo stage by breaking up the embryo into more than one group of cells. 12. State the Definition of the term clone. 13. Complete the table to describe four examples of naturally occurring clones. Natural clone example Description Starfish Bacteria (plant) Runners (plant) Tubers

10 14. Natural cloning is rare in animals, but is common in many plant species. Explain why natural cloning is common in plants. 15. Monozygotic (identical) twins in humans are an example of naturally occurring clones. a. Describe how they are produced. b. State the cell property that allows embryo to be used to produce clones. c. Outline how embyros can be cloned artificially and explain why this process is of limited use. d. Outline how embyros can be cloned artificially and explain why this process is of limited use. 3.5.U8 Methods have been developed for cloning adult animals using differentiated cells. AND 3.5.A4 Production of cloned embryos produced by somatic-cell nuclear transfer. 16. Cloning by somatic-cell nuclear transfer (SCNT) allows the creation of a genetically identical organism through transfer of a differentiated diploid nucleus. a. State the definition of the term differentiated diploid nucleus. b. Outline the steps involved in SCNT.

11 c. Dolly the sheep was the first successful cloning of a mammal from a differentiated somatic cell. Suggest one reason why Dolly died younger than normal, but of an age-related illness. d. Differentiate between the process of SCNT and therapeutic cloning. e. Cloning of a whole organism has limited use, but there are many potential uses of uses of therapeutic cloning in medicine. List the uses of therapeutic cloning. Citations: Allott, Andrew. Biology: Course Companion. S.l.: Oxford UP, Print. Taylor, Stephen. "Essential Biology 4.4 Genetic Engineering and Biotechnology.docx" Web. 19 Sep <