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IGCSE BIOLOGY SECTION 5 LESSON 2 Content Section 5 Uses of biological resources a) Food production b) Selective breeding c) Genetic modification (genetic engineering) d) Cloning Content Lesson 2 b) Selective breeding c) Genetic modification b) Selective breeding 5.10 understand that plants with desired characteristics can be developed by selective breeding 5.11 understand that animals with desired characteristics can be developed by selective breeding. c) Genetic modification 5.12 describe the use of restriction enzymes to cut DNA at specific sites and ligase enzymes to join pieces of DNA together 5.13 describe how plasmids and viruses can act as vectors, which take up pieces of DNA, then insert this recombinant DNA into other cells 5.14 understand that large amounts of human insulin can be manufactured from genetically modified bacteria that are grown in a fermenter 5.15 evaluate the potential for using genetically modified plants to improve food production (illustrated by plants with improved resistance to pests) 5.16 understand that the term ‘transgenic’ means the transfer of genetic material from one species to a different species. Selective breeding Selective breeding is a method used for many years by farmers and growers to improve crops and yields. For example, milk production or disease resistance. Selective breeding Selective breeding aims to improve the features of a species. Eg. To produce leaner pigs: 1. Select pigs with the least fat and mate them 2. Select the best of the offspring and mate these 3. Continue selecting and breeding over many generations. Selective breeding Disease-resistant wheat has also been developed by cross – breeding wheat plants with disease resistance and wheat plants with a high yield. Selective breeding Disease-resistant wheat has also been developed by cross – breeding wheat plants with disease resistance and wheat plants with a high yield. The stalk of the wheat plant has also been developed by selective breeding to make it shorter and stronger – helps with harvesting. Selective breeding Milk yield in dairy cattle has been increased by selecting bulls from high yield herds and breeding them with cows that have the best milk production Selective breeding Milk yield in dairy cattle has been increased by selecting bulls from high yield herds and breeding them with cows that have the best milk production ROSES –bred for colour, shape and scent. SHEEP – bred for quality wool and lamb production ROSES –bred for colour, shape and scent. SHEEP – bred for quality wool and lamb production APPLES – bred for colour, taste and texture ROSES –bred for colour, shape and scent. SHEEP – bred for quality wool and lamb production DOGS – bred for speed and endurance APPLES – bred for colour, taste and texture ROSES –bred for colour, shape and scent. SHEEP – bred for quality wool and lamb production DOGS – bred for speed and endurance CATS – bred for best of breed shows ROSES –bred for colour, shape and scent. APPLES – bred for colour, taste and texture SHEEP – bred for quality wool and lamb production DOGS – bred for speed and endurance CATS – bred for best of breed shows ROSES –bred for colour, shape and scent. APPLES – bred for colour, taste and texture LINSEED – bred for oil production Selective breeding Advantages: Produces an organism with the right features for a particular function. Produces a more efficient and economically viable process for farming and horticulture. Selective breeding Advantages: Produces an organism with the right features for a particular function. Produces a more efficient and economically viable process for farming and horticulture. Disadvantages: Reduced number of alleles in the population. Reduced variation, so unable to respond to environmental change. Can lead to other unexpected health problems. Genetic Modification Genetic Modification Genetic Modification Genetic modification (GM) is the use of modern biotechnology to change the genes of an organism Genetic Modification Why GM? Genetic Modification Why GM? To improve crop yields, eg. larger tomatoes, more oil from linseed plants Genetic Modification Why GM? To improve resistance to pests or herbicides, eg. Pyrethrum To improve crop yields, eg. larger tomatoes, more oil from linseed plants Genetic Modification Why GM? To improve resistance to pests or herbicides, eg. Pyrethrum To improve crop yields, eg. larger tomatoes, more oil from linseed plants To improve the shelf-life of fast ripening crops such as tomatoes Genetic Modification Why GM? To improve resistance to pests or herbicides, eg. Pyrethrum To improve crop yields, eg. larger tomatoes, more oil from linseed plants To harness the cell chemistry of an organism, eg. human insulin To improve the shelf-life of fast ripening crops such as tomatoes Genetic Modification Genes are often transferred at an early stage of development (in both animals and plants) so they develop with the required characteristics GM Stuffed Dog (not really) Genetic Modification Genes are often transferred at an early stage of development (in both animals and plants) so they develop with the required characteristics GM Stuffed Dog (not really) Characteristics can then be passed onto the offspring if the organism reproduces asexually, or is cloned. Genetic Modification “describe the use of restriction enzymes to cut DNA at specific sites and ligase enzymes to join pieces of DNA together” Genetic Modification How do we change the genes of an organism? Genetic Modification How do we change the genes of an organism? That’s a really good question – let’s start with an example Genetic Modification A hormone secreted by the pancreas, essential for the control of blood glucose. The production of human insulin by genetic engineering. Genetic Modification A hormone secreted by the pancreas, essential for the control of blood glucose. A Type 1 diabetes patient needs insulin injections to survive. The production of human insulin by genetic engineering. Genetic Modification A hormone secreted by the pancreas, essential for the control of blood glucose. A Type 1 diabetes patient needs insulin injections to survive. The production of human insulin by genetic engineering. Insulin medications were originally taken from cows, pigs or salmon. Genetic Modification A hormone secreted by the pancreas, essential for the control of blood glucose. A Type 1 diabetes patient needs insulin injections to survive. The production of human insulin by genetic engineering. Insulin medications were originally taken from cows, pigs or salmon. Human insulin first synthesised by genetic engineering in 1978. Genetic Engineering – The Process Chromosome Human cell Part of a human chromosome Human insulin gene Genetic Engineering – The Process Chromosome Human cell The gene for insulin production is ‘cut out’ of the human chromosome using restriction enzymes Part of a human chromosome Human insulin gene Genetic Engineering – The Process Restriction enzymes, found Thebe gene for insulin Human naturally in bacteria, can production is ‘cut out’ of cell used to cut chromosome the human chromosome using restriction enzymes (DNA) fragments at specific points. Chromosome Part of a human chromosome Human insulin gene Genetic Engineering – The Process Chromosome Human cell Part of a human chromosome The gene for insulin production is ‘cut out’ of the human chromosome using restriction enzymes Genetic Engineering – The Process Bacterium Bacterial DNA Plasmid = small DNA molecule, separate from the chromosomal DNA Bacteria are prokaryotic microorganisms. They do not have a distinct cell nucleus Genetic GeneticEngineering Engineering––The TheProcess Process Another restriction enzyme is used to cut open a ring of bacterial DNA. Genetic GeneticEngineering Engineering––The TheProcess Process Another restriction enzyme is used to cut open a ring of bacterial DNA. Other enzymes (ligase enzymes) are used to insert the piece of human DNA into the plasmid. Genetic GeneticEngineering Engineering––The TheProcess Process Another restriction is used cut Ligaseenzyme enzymes aretoenzymes open a ring ofreactions that catalyze bacterial DNA. which make bonds to join together (ligate) smaller molecules to make larger Other enzymes (ligase ones. enzymes) are used to insert the piece of human DNA into the plasmid. Genetic Engineering – The Process Plasmid now reinserted into a bacterium which starts to divide rapidly. VAT Genetic Engineering – The Process As it divides it replicates the plasmid, and very soon there are millions of them, each with the code to make insulin. VAT Genetic Engineering – The Process Commercial quantities of insulin are then produced. VAT Genetic Engineering – The Process The vector (the carrier) may be a virus rather than a bacterial plasmid. The viral vector is also known as a virion. Genetic Engineering – The Process The viral vector is able to transport the DNA directly into the nucleus of another cell. The vector (the carrier) may be a virus rather than a bacterial plasmid. The viral vector is also known as a virion. Genetic Engineering – The Process The viral vector is able to transport the DNA directly into the nucleus of another cell. After insertion of the DNA the protein is then produced using the cells’ own mechanism. The vector (the carrier) may be a virus rather than a bacterial plasmid. The viral vector is also known as a virion. Genetic Engineering – The Process Human insulin was the first commercially available protein produced by recombinant DNA technology. Genetic Engineering – The Process Human insulin was the first commercially available protein produced by recombinant DNA technology. Genetic Engineering – The Process Large amounts of human insulin can be manufactured from genetically modified bacteria that are grown in a fermenter Genetically Modified Crops “Major doubts have been raised over the safety of GM foods by a new study ..” “The Daily Mail’s Frankenstein Food Watch campaign has long highlighted problems with the lack of rigorous safety assessments for GM crops and food.” Genetically Modified Crops Most developments are in the experimental or trial stages. In the UK, GM crops are grown only on a trial basis. Genetically Modified Crops Most developments are in the experimental or trial stages. In the UK, GM crops are grown only on a trial basis. Developed particularly for insect / pest resistance Genetically Modified Crops Most developments are in the experimental or trial stages. In the UK, GM crops are grown only on a trial basis. Bacterium (Bacillus thuringiensis) has a toxin that kills caterpillars and insect larvae. Gene for this toxin implanted in some plant species using a bacterial vector. Developed particularly for insect / pest resistance Genetically Modified Crops Most developments are in the experimental or trial stages. In the UK, GM crops are grown only on a trial basis. have shown Plants produce the toxin and increased resistance to attack by insect larvae. Unfortunately there are signs that insects are developing immunity to the Bacterium (Bacillus toxin. thuringiensis) has a toxin that kills caterpillars and insect larvae. Gene for this toxin implanted in some plant species using a bacterial vector. Developed particularly for insect / pest resistance Genetically Modified Crops Most developments are in the experimental or trial stages. In the UK, GM crops are grown only on a trial basis. In 2002 half the cotton grown in China was genetically modified to produce a substance poisonous to the cotton bollworm, a pest of cotton crops. Developed particularly for insect / pest resistance Genetically Modified Crops Most developments are in the experimental or trial stages. In the UK, GM crops are grown only on a trial basis. Benefits of the GM cotton are a reduction in pesticide use, and increase in yields and profits, and health benefits to workers (no more spraying of pesticides). In 2002 half the cotton grown in China was genetically modified to produce a substance poisonous to the cotton bollworm, a pest of cotton crops. Developed particularly for insect / pest resistance Genetically Modified Crops Advantages • GM crops more productive and have a larger yield Disadvantages Genetically Modified Crops Advantages • GM crops more productive and have a larger yield • Can offer more nutritional value and better flavour Disadvantages Genetically Modified Crops Advantages • GM crops more productive and have a larger yield • Can offer more nutritional value and better flavour • Inbuilt resistance to pests, weeds and disease Disadvantages Genetically Modified Crops Advantages • GM crops more productive and have a larger yield • Can offer more nutritional value and better flavour • Inbuilt resistance to pests, weeds and disease • Crops require less herbicides and pesticides Disadvantages Genetically Modified Crops Advantages • GM crops more productive and have a larger yield • Can offer more nutritional value and better flavour • Inbuilt resistance to pests, weeds and disease • Crops require less herbicides and pesticides • foods are more resistant and stay ripe for longer, so improving shelf life. Disadvantages Genetically Modified Crops Advantages • GM crops more productive and have a larger yield • Can offer more nutritional value and better flavour • Inbuilt resistance to pests, weeds and disease • Crops require less herbicides and pesticides • foods are more resistant and stay ripe for longer, so improving shelf life. • more GM crops can be grown on relatively smaller parcels of land. Disadvantages Genetically Modified Crops Advantages Disadvantages • GM crops more productive and • Exact insertion of the genes is have a larger yield • Can offer more nutritional value and better flavour • Inbuilt resistance to pests, weeds and disease • Crops require less herbicides and pesticides • foods are more resistant and stay ripe for longer, so improving shelf life. • more GM crops can be grown on relatively smaller parcels of land. still a ‘hit or miss’ process. Genetically Modified Crops Advantages Disadvantages • GM crops more productive and • Exact insertion of the genes is have a larger yield • Can offer more nutritional value and better flavour • Inbuilt resistance to pests, weeds and disease • Crops require less herbicides and pesticides • foods are more resistant and stay ripe for longer, so improving shelf life. • more GM crops can be grown on relatively smaller parcels of land. still a ‘hit or miss’ process. • GM food will end food diversity if everyone grows same standard crops. Genetically Modified Crops Advantages Disadvantages • GM crops more productive and • Exact insertion of the genes is have a larger yield • Can offer more nutritional value and better flavour • Inbuilt resistance to pests, weeds and disease • Crops require less herbicides and pesticides • foods are more resistant and stay ripe for longer, so improving shelf life. • more GM crops can be grown on relatively smaller parcels of land. still a ‘hit or miss’ process. • GM food will end food diversity if everyone grows same standard crops. • GM crops could cross-pollinate with nearby non-GM plants and create ecological problems. Genetically Modified Crops Advantages Disadvantages • GM crops more productive and • Exact insertion of the genes is have a larger yield • Can offer more nutritional value and better flavour • Inbuilt resistance to pests, weeds and disease • Crops require less herbicides and pesticides • foods are more resistant and stay ripe for longer, so improving shelf life. • more GM crops can be grown on relatively smaller parcels of land. still a ‘hit or miss’ process. • GM food will end food diversity if everyone grows same standard crops. • GM crops could cross-pollinate with nearby non-GM plants and create ecological problems. • Herbicide-resistant and pesticide-resistant crops could give rise to super-weeds and super-pests that would need newer, stronger chemicals to destroy them. Transgenic Species “understand that the term ‘transgenic’ means the transfer of genetic material from one species to a different species” Transgenic Species Glofish, the first transgenic animals to be sold as pets. http://en.wikipedia.org Transgenic = an organism whose genetic material has been altered using genetic engineering techniques. Transgenic Species Glofish, the first transgenic animals to be sold as pets. http://en.wikipedia.org Glofish – fluorescence gene from a jellyfish inserted into zebrafish embryo. Fish are now brightly fluorescent in both natural white light and UV light. Transgenic Species An anti-blood-clotting agent used in heart surgery has been produced in the milk of transgenic goats. The product is in the final stages of clinical trials. Transgenic Species The gene for an enzyme, alpha-anti-trypsin, which blocks the action of the protease enzymes in the lungs of people suffering from inherited emphysema, has been transferred to sheep. Transgenic Species The gene has been inserted into milk producing cells in sheep mammary glands. The sheep now produce the enzyme in their milk, from which it can be separated and purified. Transgenic Species End of Section 5 Lesson 2 In this lesson we have covered: • selective breeding • genetic modification • genetic engineering • GM crops • transgenic species