Introduction: Genetic engineering is a process to transferred genes from one organism to another set of genes which is unrelated with each other. This process can be done because the genetic code is universal, this means that any triplet code represent the same amino acids whether it being read in bacterium, green plant, fungus or animal. The usage of genetic technology has important applications for example in pharmaceutical industry, medicine, horticulture and forensic science. Steps to Produce Genetic Modified Organisms:
There are several steps that needed to be done before genetic engineering can be completed. The first step is isolating the DNA from the source genome, which the DNA that useful to be inserted into a new organism. For example, isolate DNA from strawberry cell. Firstly, we need to mash the fruit and dissolve the fruit in a cup containing detergent to dissolve the organelles and cell membrane. Next, pour acid (NaCl) into the cup that contained the mash fruit and detergent to separate the DNA and mash fruit.
This is because (Na+) in the acid will attracted to (-) DNA and separate the DNA from the residue. After that, we need to filter out the clump with filter paper and the residue will left and pour cold-alcohol into the filtered solution and the DNA strand will float in the alcohol. This can be done because DNA is not soluble in cold alcohol. Next step after isolating the DNA is to cut the DNA strand. Restriction enzyme can be done in several ways which will produce blunt end or sticky end.
Some examples of blunt end are Alul and HaeIII while for sticky end are BamHI, HindIII and EcoRI. The restriction enzymes for each example above are different between each other and the example of the restriction are shown in the picture below. (users. rcn. com) Next step after cutting the DNA is isolating the DNA by fragment using electrophoresis. Electrophoresis is a process to separate particles including biologically important molecules such as DNA and RNA. This process is carried out on Agarose gel or on polyacralamide gel(PAG).
Both this gels contain tiny pores that act like molecular sieve where smaller particles can move quickly but larger particle move much more slowly. The present of slightly negative charge in phosphate group in the DNA will make the molecule move toward positive pole and separate the DNA fragment according to its size and charge carried. In biology, vector is an agent that transport between one organism and another but in genetic engineering, vector is ‘carrier DNA’ into which DNA fragment containing particular gene can be inserted. So, it can introduce the gene into new organism.
A bacterium such as E. coli contains two types of genetic material which is nucleoid (long double strand of DNA in the form of ring, circular chromosome) and plasmid (smaller ring than nucleoid in cytoplasm). In genetic engineering, we use plasmid as vector for cloning because plasmid is easier to be isolated from bacterium and can re-introduced to a bacterial cell to produce a new organisms with new characteristics because plasmid copy themselves independently in chromosome, so any new genes that are added to plasmid will be copied many times.
The process to re-introduce cell into new gene by using plasmid need several ways to make it a complete process. Firstly, plasmid will be cut in the form of sticky end and the same cut is used to cut out the gene from DNA. The sticky end will form a complimentary and will be combined together using ligase enzyme. The simple picture below will make an easier conclusion about this process. (www. munca. ca) The process is usually will be done in prokaryotes rather than eukaryote because of several reasons. First, manipulating genes in eukaryotes is more difficult compare to prokaryote because plasmid does not exist in eukaryote xcept yeast and if introduce does not always survive to replicate. Besides, eukaryotes are diploid organisms, so there are two forms (allele) for every gene to be engineered to nucleus but prokaryotes only have single, circular chromosome (nucleoid). So, only one copy of the gene has to be engineered into their chromosome and easier the scientists to produce new organisms with new characteristics. Producing Transgenic Animal: (www. scq. ubc. ca) The picture above explained on how to produce a transgenic animal.
There are several advantage in produce a transgenic animal. One example is production of special human blood protein (AAT). This protein enables us to maintain lung elasticity. Patients that lack with this protein will develop ephysema (destruction of walls of the air sacs). The ways to produce this protein is by cloning an egg with another somatic cell that has been genetically engineered to produce specific milk. The egg then will be implanted into a surrogate mother (sheep) and the offspring of the animal will produce milk that contained useful protein for humans.
Another product that important to human blood clotting factor known as Factor IX can also be obtained from the milk of GM sheep. Examples of Transgenic Animal: ‘GloFish’: Glofish is created by inserting genes from sea anemone and jellyfish. This glofish has been genetically engineered to produce protein that express fluorescent colour in body. Glofish began to be marketed in US in 2003 as ornamental pet fish. But, the sale of ‘glofish’ has sparked a controversial debated on ethical issue in California. Farm Animal: Genetically animal can be created to enhance food quality.
For example, swine that has been genetically modified to produce fatty acids for higher level of omega-3, and goat have been genetically engineered to produce human lysozyme in their milk. Genetically modified sheep can produce human growth hormone (HGh) and factor IV in blood clotting. Producing Transgenic Plant: The production of transgenic plants also the same as producing transgenic animal. Transgenic plants may be formed using tumour-forming Agrobacterium. The plasmid will be isolated and useful genes may be added to plasmid (Ti plasmid). Using restriction enzyme and ligase and place back in Agrobacterium.
The host crop plant will be infected and may be cultured into independent plants and will carry useful gene. The summary of this process is shown by the image below. (www. scq. ubc. ca) Examples of Transgenic Plant: Pesticide resistance in plants: Scientist has found a way to make plants resist to pesticide and kill weeds without harm the plant. They transferred a gene into the plant and enable plants to resist to certain pesticide. When farmers spray his or her genetically modified plant, the pests around the plant will die without killing the plants.
The disadvantage in this genetically modified plant is maybe genes from GM plant can be transferred to pests so the pests will become resistance to the pesticide and the plant sprays become useless. Golden rice: Golden rice is the genetic modified rice that contain a lot of beta-carotene which the precursor of vitamin A. so, when a lot of golden rice consumed, a lot of vitamin A absorb by our body. Beta-carotene gives carrot the orange colour so it’s the reason why genetically modified rice is called Golden Rice. Some opposers of GM rice fear that company will go on to develop other GM food from which they can make profit.
Maybe a large company will own the right to produce all GM food and left the traditional farmer unemployed. The Risks of Genetically Modified Food: New allergens could be created: Allergen in traditional food may be transferred to GM food. For example, a gene from Brazil nut has been introduced to soybeans. It was found that, people that allergic to Brazil nut could also be allergy to soybeans that consisted Brazil nut gene. Cross-breeding: There are probabilities that cross-breeding may occur between GM food and surrounding plants, including weeds.
This may lead to produce a GM weed that has resistance toward herbicide and thus require a greater use of herbicides which could lead to soil and water contaminate with herbicide. Pesticide resistance insect: The GM of some crops to permanently produce natural pesticide which is Bacillus thuringiensis(Bt) in maize could encourage the evolution of Bt-resistance insects and cause the spray ineffective. Antibiotic resistance may develop: Bioengineer sometime may include ‘marker’ gene to help them identify whether a new gene inserted has been successfully introduce to host DNA.
One of the ‘markers’ is for resistance to particular antibiotics. If genes coded for antibiotic consume by human, the effectiveness of antibiotic may decrease and leads to risk infected by diseases increase. News Clip On Genetically Modified Product: After 30 years, is a GM food breakthrough finally here? Golden rice, a new strain that boosts vitamin A levels and reduces blindness in developing countries, is about to be sown in the Philipines – and is the new battleground crop. Scientists say they have seen the future of genetically modified foods and have concluded that it is orange or, more precisely, golden.
In a few months, golden rice – normal rice that has been genetically modified to provide vitamin A to counter blindness and other diseases in children in the developing world – will be given to farmers in the Philippines for planting in paddy fields. Thirty years after scientists first revealed they had created the world's first GM crop, hopes that their potential to ease global malnutrition problems may be realised at last. Bangladesh and Indonesia have indicated they are ready to accept golden rice in the wake of the Philippines' decision, and other nations, including India, have also said that they are considering planting it. Vitamin A deficiency is deadly," said Adrian Dubock, a member of the Golden Rice project. "It affects children's immune systems and kills around two million every year in developing countries. It is also a major cause of blindness in the third world. Boosting levels of vitamin A in rice provides a simple, straightforward way to put that right. " Recent tests have revealed that a substantial amount of vitamin A can be obtained by eating only 60g of cooked golden rice. "This has enormous potential," said Dubock.
But scientists' satisfaction over the Golden Rice project has been tempered by the fact that it has taken an extraordinarily long time for the GM crop to be approved. Golden rice was first developed in 1999, but its development and cultivation has been opposed vehemently by campaigners who have flatly refused to accept that it could deliver enough vitamin A, and who have also argued that the crop's introduction in the developing world would make farmers increasingly dependent on western industry. The crop has become the cause celebre of the anti-GM movement, which sees golden rice as a tool of global capitalismReference:
1. Megan Rice. (2008). DNA Extraction Principles. Retrieved on February 5 2013 from http://www.slideshare.net/meganrice/dna-extraction-principles 2. State Government of Victoria, Deakin University, Australia. Genetically Modified Food. (2012). Retrieved on February 6 2013 from http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Genetically_modified_foods 3. 4 Examples of Genetically Modified Plant.(2002). Retrieved on February 6 2013 from http://www.bionetonline.org/english/content/ff_cont3.htm 4. Elisabeth H.Ormandie, Julie Dale, Gilly Griffin. Genetic Engineering of Animal: Ethical Issues, Including Welfare Concerns. ( 2011). Retrieved on February 6 2013 from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3078015/ 5. C.J.Clegg. Biology for the IB Diploma.2007. Britain. Hodder Education.