The ability of humans to manipulate DNA is a mixed blessing Genetically modified organisms are made moving the DNA from one species to another. DNA contains genes which code for proteins. For plants and bacteria; restriction enzymes are used to cut a DNA segment from a desired gene source and a bacterium plasmid. They are joined using ligase enzymes and inserted into the plant chromosome or host bacterium. For animals the recombinant DNA is injected into an embryo and transferred to a recipient mother. The organisms will now express a new protein. Proteins determine form and metabolism.
Genetic engineering changes the natural DNA of living things, cutting across species boundaries. Transgene’s effects vary with position. The foreign genes enter the host DNA haphazardly disrupting natural coding. Gene's only replicate faithfully because specialised proteins prevent most errors. Some organisms repair miscoding or have proteins that alternatively splice messenger RNA and thereby produce many different proteins from a single gene. Alien genes and the host's systems will to be unpredictable. In nature a trait is guaranteed by millennia of testing. --------------------------------------------------
Much of the genetic engineering now being used commercially is in the agricultural sector. Plants are genetically engineered to be resistant to herbicides, produce their own pesticides, have viral resistance, and to convert nitrogen directly from the soil. But these transgenes can insert into the genetics of relatives through cross-pollination, creating superweeds resistant to herbicides, pests and viruses. This may increase pest’s immunities and antibiotic resistances, transfer of pathogenic genes, the creation of new viruses, and introduce allergens into the food supply.
Worse, these problems will be faster growing, disease resistant, and heat, cold, and drought tolerant. These and mutations may cause irreversible disaster. Planting engineered herbicide resistant crops will allow farmers to spray higher level of herbicides without damaging crops, a cycle that may contaminate our environment and poison animals. “Marker genes” used to see which cells took up the foreign DNA cause a problem with antibiotic resistance. These markers are usually antibiotic resistant so cells with no foreign DNA can be killed by antibiotic treatment.
Virulent genes with the ability to penetrate immune systems will inevitably increase the frequency of horizontal gene transfers. Once genes can freely transfer between species, species start to lose their distinguishing characteristics. Reducing biodiversity and costing us undiscovered natural miracles. Research is ongoing in growing agricultural products directly in the laboratory. Food and fibre being are grown in tissue culture in giant bacteria baths much cheaper than the price of growing them on the land. The shift to indoor agriculture could herald the eventual end of the agricultural era.
Millions of farmers in both the developing and developed worlds would be uprooted from the land. Conversely genetically engineered plants as chemical factories are slowly being released outside. Controversial genetic modifications are also being done on animals. A combination of genetic engineering and cloning is being used for the development of market animals modified for increased growth and reduced fat. GE animals are being developed as factories for the production of pharmaceuticals and as sources of organs for transplantation into humans.
In order to overcome organ rejection problems pigs are being modified with human genes so the organs of their offspring can be transplanted into humans more successfully. Transgenic chickens are engineered with a bovine growth hormone gene. This unbalances their entire metabolism. The chickens grow at twice their normal rate, but their legs can no longer carry their weight and the animal suffers leg pain and deformities. This also places a huge strain on their hearts and lungs. These chickens often suffer heart failure before they are two months old.
Many other die due to infectious diseases caused by intensive breeding and battery caging. Animal lovers are very angry about such mutations induced upon living creatures. Researchers are genetically engineering disease carrying insects. Destroying their disease potency, or so that their offspring are sterile. Insects are also being genetically engineered to attack crop predators but this may end as badly as species introduction did as testing is done in a closed system and profits tend to outweigh extensive testing.
Potentially our most beneficial, and our most hazardous, modifications are being done on bacteria. Genetically engineered (GE) organisms are being developed to extract minerals from the ores in which they are embedded. Others have been genetically engineered to clean up oil spills, neutralize dangerous pollutants, absorb radioactivity and to transform waste products into ethanol for fuel. These are amazing advancements, but inevitably one of these radical applications will cause an unforseen side effect or the bacteria will mutate into an undesirable strain.
Commercial release of GE Sinorhizobium meliloti has resulted in the establishment of the microbe in the soil in millions of acres of cropland, where it can spread antibiotic resistance genes for antibiotics that are extensively used in medicine and agriculture. Modified soil bacteria spread into the wild could seriously compromise the soils ability to support plant life. Genetic screening is already used to screen for some hereditary conditions. Research is ongoing in the use of gene therapy for the correction of defective human genes that cause certain genetic diseases.
Genes can be introduced into the body through the use of genetically engineered vaccines and other medicines, and through the use of animal parts genetically engineered with human genes to combat rejection problems. They are genetically engineering human skin and soon hope to do the same with entire organs and other body parts. -------------------------------------------------- When engineered organisms are released into the environment, they risk our future but a microbe that could generate hydrogen or extract atmospheric carbon dioxide could save us.
Most scientific research is dependent on artificial closed system models, but the planet is an open system. Can we entrust our food supply and future to those motivated by profits? What seems to be safe in the laboratory will not always be valid in the natural world. Ecosystems that support the biosphere are going to be irreversibly disrupted, but how much? -------------------------------------------------- Bibliography Commoner, B. (2002). Unraveling the DNA Myth, [internet]. Harpers Magazine, [accessed 18 JUNE 2008. ] Davidson, K. (2002). Synthetic life, [internet]. San Francisco Chronicle, San Francisco. accessed 18 JUNE 2008. ] Druker, S. M. (2004). WHY CONCERNS ABOUT HEALTH RISKS OF GENETICALLY ENGINEERED FOOD ARE SCIENTIFICALLY JUSTIFIED, [internet]. Alliance for Bio-Integrity, Iowa. < http://www. bio-integrity. org/health-risks/health-risks-ge-foods. htm > [accessed 18 JUNE 2008. ] Fong, M. (2002). GENETIC TRESPASSING AND ENVIRONMENTAL ETHICS, [internet]. [accessed 18 JUNE 2008. ] Gibbs, W. W. (2004). Synthetic Life:Biologists are crafting libraries of interchangeable DNA parts and assembling them inside microbes to create programmable, living machines, [internet].
Scientific American, http://online. sfsu. edu/%7Erone/GEessays/SyntheticLife. htm Lecornu, B. & Diercks, T. (2000). Biology: levels of life. Briton Books, Adelaide. Oshinskie, M. (200? ). The Rest Of The Story Behind Genetic Engineering, [internet]. http://online. sfsu. edu/%7Erone/GEessays/tokarinterview. htm [accessed 18 JUNE 2008. ] Rifkin, J. (1997). The Biotech Century - A Second Opinion : The Marriage of the Genetic Sciences and the Technologies Reshaping Our World, [internet]. < http://www. amazon. com/exec/obidos/ISBN=087477909x/darwinanddarwini/>