Research into impacts of genetic modification
Altering the genes in an organism has a great many effects on the characteristics of the organisms. Introducing such an organism into the environment carries the potential risk of altering the delicate balance of an ecosystem in the same way as introducing any other new organism into the environment. Possums, introduced into New Zealand in the 1850s to establish a fur trade, are a good example. With no predators, the population has grown out of control, posing a significant threat to native flora and fauna.
Many of the possible environmental effects will be specific to the organisms being introduced, so a case-by-case approach is considered the most effective way of managing possible impacts. That is why, under New Zealand law, anyone applying to introduce a new organisms, including a genetically modified organism (GMO) into the environment must supply the Environmental Risk Management Authority (ERMA) with extensive information about its impact on the environment.
However, there are some potential environmental impacts that are common across a range of genetically modified organisms.
The Royal Commission on Genetic Modification, among its recommendations to Government on managing genetic modification in New Zealand, suggested there should be further publicly funded research to understand the social and environmental impacts of GMOs. As a result, in the three-year period since 1999-2000, at least $7 million a year has been put towards research programmes into the environmental, social and economic impacts of GM. The results of the research can be used in making decisions about whether or not a particular GMO should be released, and what conditions might have to be put on that release.
Summaries of this research are given below.
Vertical gene transfer
This refers to the spread of genetic material through normal sexual reproduction to the same species or related species. It is possible the modified genes in a GM crop could spread via pollen to a related native species. A herbicide-resistant GM plant might be able to pass on that characteristic to its weedy relatives, creating weeds that cannot be controlled by that herbicide. The modified genes could also spread to conventional crops of the same species.
New Zealand scientists are assessing the likelihood of vertical gene transfer occurring in the New Zealand environment. They are doing this by investigating the invasiveness of GM crops and the potential for the spread modified genes to other crops and related species. Specific research projects include documenting all the crops grown in New Zealand and identifying the weedy relatives of those crops and related native species that could be affected by the release of GM crops.
Horizontal gene transfer (HGT)
This refers to the movement of small fragments of DNA from one organism to another without sexual reproduction. Scientists know that, under some circumstances, the DNA from GMOs can be transferred into bacteria. Researchers here are investigating if there is anything about New Zealand soils that could increase the likelihood of horizontal gene transfer from GM plants to soil bacteria. They are also investigating how well the transformed bacteria survive, and the extent to which they could themselves further spread the modified DNA.
Impact of GM plants on bees
One major use of GM technology is to insert genes into crops that produce insecticides. The most commonly used insecticide is a toxin from the bacterium Bacillus thuringiensis (Bt for short), though other insecticides are also used. It should be pointed out that the modified gene is not always expressed (turned on) throughout the whole plant – it may, for example, be confined to the leaves of the plant. However, if the gene for an insecticide is expressed in pollen then there is a chance that the insecticide may harm bees that eat the pollen. Researchers have been testing the effect on bees of different insecticides in concentrations likely to be produced by GM plants and have so far found little or no effect.
Impact of GM plants on natural enemies
Insecticides expressed by GM plants may not only harm the target pest species. They could also pose a danger to the pest insect’s natural enemies when they ingest the pest insect, along with traces of the toxic pesticide. To date researchers have found no effect from the insecticide produced by one GM plant on a single native predator. However, each crop, prey insect and predator species will need to be evaluated separately on a case by case basis.
Other researchers are working on the impact of GM pine trees on insect predators. They are also developing ways to measure the effect of genetically modified pasture plants on native invertebrates such as insects and worms.
Impact of GM plants on the soil ecology
Insecticides and other products released by GM plants are released into the soil, and researchers are monitoring the effect that Bt transgenic potatoes have on New Zealand soil. So far, only minor and transient effects have been found, though the research is still going on.
Economic impacts of GM crops
Even if GM crops have little or no environmental impact, some people have reservations over their effects on human health. Others are concerned over the impact the presence of GM material in conventional crops may have on our overseas markets and New Zealand’s “clean, green” image. Economists have been using a number of economic models to assess the potential economic impacts of releasing genetically modified organisms in New Zealand. The results so far indicate that there are likely to be economic benefits in producing specialised GM products for a niche market, but not for large scale food crops.
Community perspectives
Some people in the community are worried about the use of genetic modification for ethical, spiritual or cultural reasons. Research is going on investigating the various attitudes to GM, including Māori perceptions of the technology.
Where can I find more information?
The Ministry for Research, Science and Technology has published a report Implementing the Government's response to the Royal Commission on Genetic Modification's recommendations on research priorities describing in more detail the research underway in response to the Royal Commission’s recommendations and discussing how it will contribute to decision making on GM and biotechnology in New Zealand.
Last updated: 17 September 2007
