Genetically Modified Insects: What next?

by jeeg 20. June 2010 00:01

 

Most of us probably don't think about insects when we hear about Genetically Modified Organisms (GMOs). Yet many scientists believe that genetically modified (GM) insects hold great promise by providing a powerful tool to prevent unnecessary deaths. Approximately half the world's population is at risk from insect-borne diseases such as malaria, sleeping sickness and dengue fever. Millions of people are killed by insect-borne diseases and hundreds of millions more are incapacitated every year. At the same time, damage and disease transmission to crops and livestock by insects has a significant global socio-economic impact. Increasing resistance to pesticides, GM crops and climate chaos are making these insect-pests a growing problem. In laboratories around the world, scientists are using genetic engineering technologies to modify insects at DNA level to address important concerns including:

1. Socio-economic challenges such as increasing crop yield and production; and 
2. Public health challenges such as human and animal well being.

There are concerns about how this GM technology fits in with other approaches to manage insect-borne diseases and the long term consequences of releasing GM insects into the wild. What are the benefits, risks and scientific uncertainties associated with such transgenic insects?

The Arizona Experiment

A few years ago, at a secret location in Arizona, genetically modified pink bollworms -- Pectinophora Gossypiella -- were released to see how they behave in the wild. They were the first GM insects to be released anywhere, and they were freed under netting. The intent was that if the experiment was deemed a success, the insects would be further modified and released into the great wide spaces where they would breed but produce no offspring that survive. In effect, they were modified to destroy their own species.

GM Crop Companies

Mutant insects are bad news for GM crop companies like BASF, Bayer-Aventis, Dow, Dupont, Monsanto and Syngenta because they sell genetically engineered plants to counter insect-pests etc. Farmers complain bitterly about the exorbitant prices charged and the fact that GM crops may not yield promised harvests or 'free' seeds for the next plantation. For example, Monsanto's GM crops are marketed as resistant to the insects which devour them but they need to be typically purchased every season and a good harvest may not be guaranteed. These practices have led to thousands of farmer suicides in Asia. To avoid paying GM crop companies, many farmers back the alternative, which is genetic modification of the insect itself. At the moment, farmers can:

1. Use chemical sprays to kill the insects; or 
2. Irradiate insects in a laboratory because radiation makes the insects sterile.

Both measures are expensive. To find a cheaper way, the idea is to alter the insects' genes so that the bugs are rendered sterile. If genetically modified (GM) insects work, the farmers would then not have to buy GM crops from biotech companies. But the key question is: Will they work and will they be safe?

Key Applications

1. Advances in biotechnology have allowed for the possibility that genetically modified (GM) insects could be used to control insect populations or even replace them with 'harmless' engineered varieties, lessening the need for pesticides.

2. Insects are being genetically sterilised so that they no longer transmit disease through reproduction. Other approaches allow reproduction but disrupt the transmission of parasites. For example, GM mosquitoes are incapable of transmitting malaria, which is contracted by 300 - 500 million people annually and kills between one and three million worldwide per annum.

3. Insects are being engineered to produce pharmaceutical proteins. For example, GM silkworms are able to produce pharmaceutical and industrial proteins, like those used to create a particularly strong spider silk. This is turn can be used in the manufacture of bulletproof vests, parachutes and artificial ligaments.

4. Honeybees are being genetically engineered so that they are resistant to diseases and parasites, which have devastated the honeybee population in the last decade.

5. Kissing bugs are being genetically modified so that they are unable to transmit Chagas' disease, which currently infects 16 - 18 million people annually and kills around 50,000 people worldwide per annum.

Uncertainties

The scientists involved say the strictest safeguards are in place. However, there is uncertainty about the lasting effects GM insects would have on ecosystems, public health and food safety once released. For instance:

1. Spread of Transgenic Traits: The success of some GM insects is contingent on the ability of fertile GM insects to replace wild insect populations and become established in the environment. Release of fertile GM insects increases the potential that transgenic traits could spread throughout the insect population, potentially making pre-existing pest problems worse or creating hitherto unforeseen and altogether new challenges.

2. Unintended Consequences: It is also possible that GM insects released to control the spread of disease could actually have the unintended consequence of enabling an insect to more effectively spread disease or even carry a human disease it was never before able to transmit.

3. Food Safety: There is the possibility that modifying the genetic composition of food-making insects such as honeybees could alter the composition of the honey they produce, potentially creating a food safety concern at one level and a human health hazard at another.

All of these uncertainties need to be carefully addressed by regulators both domestically and worldwide prior to the introduction and release of GM insects into the wild.

Source: MI2G

 

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