Genetic modification - the global story
Genetic modification is a technology developed in the past 30 years for altering the characteristics of living organisms, such as plants and animals. Genetic modification is also referred to as GM, genetic engineering or GE.
Internationally, genetic modification is being used to help better understand the genetic make up of humans, plants and animals. This increased understanding is being used in a number of ways. It is used in medical research to look for cures for diseases such as multiple sclerosis and cystic fibrosis, and in agricultural research to develop animal medicines and vaccines, and crops with new traits such as herbicide resistance or the ability to produce their own insecticide.
Medical and veterinary uses
Genetic modification is used both to aid medical researchers in understanding the cause of diseases and to develop possible cures.
The Human Genome Project used genetic modification to help in the replication and identification of each human gene. This information is now being used by medical researchers to explore the causes and possible cures for many diseases.
As our understanding of the genetic make up of human cells and the causes of many diseases increases, researchers are being provided with more and more information to aid them in their search for cures. For example, international research is underway to investigate the use of gene therapy to cure genetic disorders such as cystic fibrosis and Parkinson’s disease.
GM is often used to help in the production of medicines. For example, GM has successfully been used to modify bacteria to produce insulin that is identical in structure to that found in the human body. People suffering from diabetes used to use insulin from pigs. This could lead to complications in some cases because of the differences in structure between pig and human insulin. Using human insulin decreases the risk of some side effects, such as allergy or other reactions that can occur with animal-sourced medicine.
There are also vaccines available that contain a genetically modified version of the disease-causing organisms. For example, GMO vaccines against cholera and feline leukaemia are both available overseas. The genetically modified organisms have had the toxic part removed, so that the body will react to the presence of the organism and produce antibodies, without suffering the ill effects of the disease itself.
In addition, other vaccines are produced by using GM technology to copy the antigen of the disease causing organism. This is the part of the disease causing organism that stimulates the immune system to produce antibodies against the disease. This is a safer approach to vaccination than using the disease causing organism in the vaccine. The hepatitis B vaccine is produced through this method in New Zealand (See How GM is being used in New Zealand research for further information).
GM crops
Although GM crops are not grown commercially in New Zealand, around the world an estimated 67.7 million hectares were planted in 2003 – an area more than twice the size of New Zealand and a 15% increase from 2002 [James C. (2003). Preview: Global status of commercialised transgenic crops: 2003, ISAAA Briefs No. 30.ISAAA:Ithaca, NY. Available at www.isaaa.org.]
Six countries account for most of the GM commercial crops. The United States dominates, with 63% of the global acreage. Argentina is next with 21%, Canada accounts for 6%, Brazil and China 4%, and South Africa 1%.
What GM crops are being grown overseas?
Four crop varieties (soybeans, cotton, canola/oilseed rape and maize dominate commercial GM crop production, In 2003, GM varieties accounted for 55% of the world's soybean crop, 21% of commercial cotton plantings, 16% of canola/oilseed rape, and 11% of maize plantings. Other crops, such as papaya and squash in the United States, and carnations in Australia – are grown in only very small areas.
Most of the GM crops on the market have been developed to tolerate particular herbicides, resist specific insect pests, or both. Some of the less common GM crops resist certain plant viruses. A number of GM plants that were grown in the past (eg, tomatoes) are no longer produced commercially due to lack of consumer demand, regulatory blocks, or other commercial factors.
While work on this first generation of genetically-modified crops has concentrated mainly on herbicide and insect and virus resistance, work is now going on to develop plants that withstand drought, are less temperature-sensitive than their conventional counterparts, or can grow in salty soils. More research is also going on into how GM might be used to develop plants that have enhanced nutritional qualities – known as neutraceuticals. Examples of this research include canola that has been modified to produce a low-cholesterol oil, tomatoes with a higher level of an antioxidant, Lycopene, rice with added Vitamin A, and cassava with higher protein levels [http://www.whybiotech.com/index.asp?id=2348]. These are all still in the development stage. Meanwhile, scientists in Japan have succeeded in producing coffee plants with 50 to 70% less caffeine by suppressing the coffee plant gene that is responsible for the formation of caffeine.
Another area of research, and one that is highly controversial, involves modifying plants to contain medicines and vaccines – a process that is known as “pharming” [http://www.bbc.co.uk/health/genes/future/treatment_5.shtml]. To date, a number of food plants have been used as “plant factories”, and critics are concerned that the drugs could pass into the food chain. This was highlighted when corn from plantings in Iowa modified to produce medicines for diabetes and diarrhoea was found to have become mixed with soybeans [http://www.lifesciencenz.com/news-detail.asp?newsID=3002]. If such “plant factories” are ever developed in New Zealand however, it is likely that they will be grown only under strict containment.
Environmental protection
Some researchers are investigating whether genetically modified trees, grasses and other plants can be used to removed toxic materials from the soil. One project in the United States is experimenting with GM trees to see if they will clean up a site that is contaminated with mercury.
Last updated: 17 September 2007
