Genetic Engineering. Vector, plasmid, gene, genetic engineering, genetically modified (GM), insulin

Transcription

1 Genetic Engineering Vector, plasmid, gene, genetic engineering, genetically modified (GM), insulin Learning Outcomes You will be able to: Describe the importance of being able to locate the position of genes on chromosomes. Describe the techniques involved in Genetic Engineering and show how this technology can be used to combine genetic material from two different species. Explain how genes can be removed from chromosomes and inserted into different chromosomes. Explain why bacterial cells are used in genetic engineering. Describe how insulin or human growth hormone is manufactured using bacterial hosts and the benefits arising from this. Natural Transfer of Genetic Information Genetic information can be transferred from one cell to another by natural means. E.g. a copy of a bacterial plasmid (circular molecule of DNA) can be passed from one bacterium to another and the DNA in a virus can be inserted into a host cell that is being attacked by the virus. DNA can also be transferred from one cell to another artificially by genetic engineering. Genetic Engineering In recent years scientists have discovered that genetic material can be transferred artificially from the cells of one species to the cells of another completely different species using techniques called genetic engineering. 1 P a g e

2 An example of Genetic Engineering An example that is commonly used to explain genetic engineering is that of insulin. Insulin is a protein hormone produced by the pancreas which helps to regulate the concentration of sugar in blood. One form of diabetes results from some people s inability to produce functioning insulin. People with this form of diabetes must inject insulin into their bloodstream in order to control their blood sugar levels. In the past, the only source of insulin was from animals. It was extracted from the pancreases of pigs and cows. This was not ideal. Today, people with this form of diabetes can be given pure human insulin through genetic engineering. The steps of genetic engineering 1. The gene for a particular protein that you want to produce needs to be identified in the source chromosome and extracted. Enzymes are used to cut out the gene. 2 P a g e

3 2. The DNA that has been extracted from a human source must be added to a vector. A vector is just a piece of DNA which carries our gene. Bacterial plasmids are common vectors. The plasmid is cut open using an enzyme, and then the gene is joined to the plasmid. 3. The plasmid can now be inserted into a host cell. Bacterial cells naturally exchange plasmids and so they will readily take up any plasmids they are exposed to. Once the plasmid is in the host bacterial cell, the cell will make many copies of it. When they do this, they unwittingly also make many copies of our human insulin gene. 3 P a g e

4 4. Given the right conditions, the host bacterial cell will divide. As they do, they will be making copies of our human insulin gene. 5. The bacterial cells will begin expressing the gene. This means they will actually make the human insulin protein. 6. The insulin can be collected, purified and then given to people with diabetes. Learning Activity 1 1. Name an organism used in genetic engineering. 2. Give an example of a product manufactured using genetic engineering. 3. Describe the use of this product in humans. 4. Describe what a plasmid is. 5. State 2 advantages in using bacteria for genetic engineering. 6. Insert and complete the Genetic Engineering diagram into your notes. 4 P a g e

5 Genetically Modified (GM) Organisms The transfer of genes from one organism into another has been applied more widely in recent times. Genes have been taken from a wide variety of different organisms and transferred into various crop plants to improve yield. These are known as genetically modified (GM) crops. Crop Rice Rapeseed Tomato Potato Modification & Advantage Genes from daffodil and soil bacteria allow the rice plant to produce vitamin A in its seeds. Genes from other organisms that give the crop herbicide resistance allow herbicides to be used to kill weeds among the crop, increasing yield Soil bacteria carry genes from other bacteria that code for insecticide protein into tomato cells, so increasing yield Genes from other organisms give potato plants fungal resistance, so increasing yield GM organisms offer the potential for great benefits to humans but there are also issues connected to their production and use. 5 P a g e

6 Benefits & Issues with GM organisms Benefits GM crops and animals can be higher yielding and better tasting. They can increase food security for increasing human populations. They can have a positive impact on the environment through the potential for decreasing pesticide use. Issues There are safety issues related to human health. Potential for unintented release of genes into wild populations. Concern of over domination of food production by GM companies. Ethical issues related to tampering with nature are raised. Concern that we simply do not know or understand the potential problems. Learning Activity 2 1. Construct a table to show a list of genetically engineered food and medicines. For each example explain the benefit to humans of the genetic modification. 2. Describe why some people have concerns about the use of genetic engineering in the production of GM organisms. 6 P a g e

7 Golden Rice - an effective source of vitamin A Tomatoes with a longer shelf life In groups, choose one of these genetically engineered products or another of your choice and research it using the Internet. Making sure everyone has a role, prepare a 5 minute presentation for the rest of the class including: A statement of what the product is include whether it is available or being developed now Information about the host organism Information about the source of the added genetic material The case for the product The case against the product The group s opinion of the product A list of References to show that the information you present is from a reliable source. Less toxic rape seed oil Blight resistant potatoes Humulin - effective control of diabetes 7 P a g e

8 Enviropig The Enviropig was a pig which has been altered to include genes from E. coli (a bacterium) and mice. The inclusion of these genes meant that the pigs were better able to digest their food, making their manure less harmful to the environment. This project was closed in June 2012 due to loss of funding. Extension Task Use the internet to research some of the more extreme examples of genetic engineering e.g. Enviropig, venomous cabbage, glow-in-the-dark cats and medicinal eggs. Produce a fact-file giving 4 examples of extreme genetic engineering. Include the following information: - The name of the organism - Explanation of how the organism is genetically modified - Benefits of the modification 8 P a g e