UNIT 5.GENETIC REVOLUTIONKEY TEMS*GENETIC ENGINEERINGIt is a set of techniques and laboratory methods used to construct recombinant DNA molecules.*RECOMBINANT-DNA:It is an artificial DNA created by combining two or more DNA molecules of different organisms.*TRANSGENIC ORGANISM OR MODIFIED ORGANISM (GMO)It is an organism obtained by Genetic Engineering techniques.When these organisms are used in industry they produce transgenic products.HOW TO GENERATE A GMOA GMO is generated in 4 steps:1. First of all we extract the DNA from a human cell.Then we cut it with restriction enzymes. The enzymes recognize specific sequences of sixnucleotides, these sequences are palindromic. The sequences are palindromic when they areread equally in one strand from right to left than on the other strand from left to right.2. A plasmid is isolated form a bacterium (Escherichia coli). This plasmid is cut by the samerestriction enzyme used in step 1. Now we have a lineal molecule with the same enpoints than thesequences obtained in the step 1.3. The DNA fragment of the human cell is attached to the plasmid molecule. As both moleculeshave the same endpoints they tend to joint together. The enzime DNA ligase seals the joints.4. We introduce the recombinant DNA in a bacterium. This process is called genetictransformation. We select the GMO bacteria with the gene we want to and we multiply it by makingit grow indefinitely.
APPLICATIONS OF GENETIC ENGINEERING*TRANSGENIC PRODUCTS IN THE PHARMACYThere are many transgenic medicaments on the market.An example is the insulin. Insulin is a peptide hormone that regulates blood glucose levels. InSpain there are two and a half million diabetics that need this hormone. Years ago, insulin wasobtained from the pancreas of pigs, but to produce 1 kg of insulin 60,000 to 100,000 pigs weresacrificed .Nowadays insulin is obtained using genetic engineering. The recombinant DNA formed by thegene of human insulin and a plasmid is introduced into a bacterium (Escherichia coli). When thisbacterium multiply, billions of bacteria that produce insulin are generated. This insulin avoids theproblems of rejection.There are many more examples of medicines produced by genetic engineering: the human growthhormone, antibiotics and vaccines. It is made possible that some animals produce in their milkthese therapeutic proteins.Steps: 1) we create a recombinant DNA formed by a gene of factor VIII and a plasmid 2) we insert the recombinant DNA in embryo cells 3) the embryos are introduced in a cow 4) a new transgenic cow will be born with the gene of factor VIII 5) we will obtains the factor VIII from its milk(factor VIII is involved in blood coagulation)*TRANSGENIC PRODUCTS FOR AGRI-FOODThe firs massively commercialized GM foods were vegetables that resisted the treatment withherbicides and the attack of different plagues. The most famous of all is the Bt corn. They aretransgenic plants that resist the attack of moths and beetles because they contain a gene from thebacterium Bacillus thuringiensis that encodes for a protein that breaks the digestive tract of theseinsects. This protein is completely harmless to mammals.Another GM product that has been harvested successfully in many countries in the world is thecotton. In India, Bt cotton is grown since 2002 and thanks to it, the use of insecticides has beenreduced up to 70%.It has been developed transgenic crops that affect physicochemical, organoleptic or nutritionalproperties. For example, there has been created transgenic tomatoes or melons that haveinhibited the path of maturation, so it is possible to control them until it is offered to the consumer,transgenic potatoes that don´t get brown when they are cut, seedless grapes, etc.The most important improvements are those related to the nutritional properties of food. So thereare foods with a higher amino acid content, with better fatty acid composition, etc.
*CONSEQUENCES FROM THE USE OF TRANSGENICSThere are three important consequences from the use of GMOs:1. Genetic engineering involves an increased of directionality. This means that human beings arecapable of selecting a particular gene and insert it in a other genome.2. The results with genetic engineering are obtained much earlier.3. There is a jump of the species barrier. This means that we can mix genes from differentspecies.The use of transgenics has some ethical repercussion. For example transgenic plant wiht a genefrom an animal it could be a problem for a vegetarian or a transgenic plant with a gene forma pigfor a Muslim.Genetic engineering is a powerful tool to create new organisms with interesting applications in theworld of medicine and health, agriculture and livestock, or chemistry and pharmacy.*TRANSLATE INTO ENGLISH:-ingeniería genética -aislar-ruta de maduración -plásmido-mejoras -bacteria-algodón -bacterias-maíz -gen-cadena de ADN -vacunas-antibiótico -embrión-evitar -sin semillas-proteínas terapéuticas-escarabajo-polilla-inocua-extremos de una cadena-organismo modificado genéticamente-enzima de restricción-sellar-insulina-rechazo