Genetic modification is at the frontier of biological knowledge. It's only been a few a few years since the Human Genome Project was completed, although genetic modification of organisms has been ongoing since the seventies. It's precisely because the technology is less than perfect that there are voices raised in concern. The problem for both the proselyte scientists who work for the industry and the journalists who attempt to put the other side of the debate is that the subject is complex: there are no easy answers, no explanations that are without caveats.

So to begin at the beginning. Each living organism has a DNA code, a strand of nucleic acid in the famous double helix shape that contains all the genes that describe that organism. The number of genes varies with the complexity of the organism they describe; thus simple organisms have fewer genes than complex ones. This fact led to the assumption that each gene codes for a single protein that in turn serves a particular purpose; for example that there's a gene for blue eyes, another for red hair, another for height. The completion of the Human Genome Project has given us some disturbing findings - not least that this simple paradigm of each gene pairing with a protein is too simplistic a model. The final tally of about 30,000 genes for the human being doesn't tally with the 100,000 or so proteins that we contain.

The principle of genetic engineering isn't a new one. Farmers have been doing it for millennia. Out of a field of wheat there will be mature seed heads that have bigger seeds than others. Keeping only those seeds for the next generation is called selective breeding. Over many generations selective breeding has ensured more of the qualities that the farmer wanted - for example greater yields or better adaptations to frost or drought. Domestic animals have been selectively bred for better milk production, leaner meat and whatever else the market demanded. What differentiates the current thrust of genetic modification from this, is that now it's possible to take a gene from one organism and add it to the genome of a different organism. An example is taking the gene from an Arctic flounder that stops its blood from freezing and putting it into the cucumber genome - producing a cucumber that's frost hardy and doesn't need a heated glass house. With this technique there's no need to wait until a fish mates with a cucumber.

Although the technology that performs this task is at the frontier of science, the underlying principle is surprisingly crude. A gene gun is just what its name suggests: you load it with the genes that you want to insert and you shoot those genes like a scattergun at the genomes that you want to modify. And just like a scattergun the results aren't predictable. The modifying genes will attach themselves to some genomes, but not to others. The way to find out which ones have transferred successfully, leads us to first major problem that needs addressing. The standard procedure is to add a marker gene to the modifying gene and that marker gene is an antibiotic resistant one. You fire your gun, you apply an antibiotic, and anything that survives must have the new modifying gene. You see the problem? Antibiotic resistance is included in the package.

Even so, this assumes that if a modifying gene has been successfully inserted, then the results should be the same. Actual practice has shown that results are far from predictable. Genetically modified cotton failed in different ways in many American states and caused catastrophe for thousands of farmers in India. It's worth doing a little science to find out why. The GM cotton involved here was called Bt Cotton. That 'Bt' stands for bacillus thuringiensis, a soil bacteria similar to bacillus anthrax, of which more in a moment. Without delving too far into the science of genetics, it is clear that where a modifying gene ends up in the genome of the host is important. The scattergun process of inserting the gene takes no account of this. The order in which the genes are read makes a difference, (the position effect) as indeed do the genes on either side of the modifier gene in the DNA, resulting in the creation of different proteins and thus unpredictable results depending on where the scattergun has scored a hit.

This same Bt is found in GM cotton, in GM maize and also in GM potatoes. The Bt produces a toxin in every cell of the organism, so that an insect attempting to eat a Bt potato will die. Those Bt potatoes and Bt maize have long been on sale in America to the public with no labelling to inform the consumers of what they are eating. The Food and Drugs Administration never tested Bt foods, on the basis that Bt was a pesticide and not a food additive, so therefore was not subject to their health tests. When the manufacturers, Monsanto, tell you that there is no research showing any harm caused by human ingestion of Bt foods they're telling the truth. No such research was ever properly undertaken.

What worries people like me most about GM foods is something called Horizontal Gene Transfer. This is gene transferral from one species to another, outside of the laboratory. Some years ago I interviewed Dr. Patrick O'Reilly of Monsanto in Ireland and I put my fears to him. He replied, 'I don't think that that is realistic. Horizontal gene transfer occurs in nature anyway, albeit rarely. The mechanisms for transferring genes are complex and it's extremely unlikely it could take place outside the laboratory.'

You may remember I mentioned antibiotic resistant marker genes. These are commonly referred to as ARMs and occur in genetically modified foods. Dr. O'Reilly's answer above faithfully follows the industry line here, based on studies done in the 70s and early 80s that claimed that ARM genes cannot survive the passage through our digestive tract. Today, with more sensitive measuring equipment, we know that to be untrue. Animal feeding studies in the late 80s confirmed that DNA not only survives digestion, it can be found in the blood, the spleen, the liver and intestinal tract for up to five days after ingestion. GM DNA can even travel via the placenta into unborn mice. It's more than possible that ingestion of ARMs could result in antibiotic resistance being transferred, a fear that resulted in The World Health Organisation, the British House of Lords, the American Medical Association and the Royal Society all calling for the phasing out of ARM genes.

However, there is a more worrying element to gene transfer. This is complicated, but is worth following. All cells have their own defensive mechanisms, which is one of the reasons that adding genes to a genome is difficult. A virus is able to accomplish this task - it can hijack a cell's genetic machinery and then use it to manufacture copies of itself. Molecular biologists borrow this ability of the virus to attach a 'promoter' to modifier genes. This enables them to get past a cell's defences. The most commonly used promoter is the Cauliflower Mosaic Virus or CaMV, which ensures that the inserted gene remains 'switched on'. The problem is this: there is no way of controlling what other genes the promoter turns on. In effect it's a kind of Russian Roulette - turning on genes that were otherwise inactive could result in the creation of new toxins, allergens or even cancers. The addition of CaMV to GMOs may be one cause of their unpredictability.

One of the surprises to come out of the Human Genome Project was that only about 1.4% of our DNA has been identified as genes. The rest, once called 'junk DNA', was considered as useless debris left over from aeons of evolution. Some of this DNA is made up of dormant viruses that have worked their way into our DNA over the millennia. There's a real fear that the CaMV promoter could reactivate long dormant viruses.

You might wonder why these facts - and many others - have not been brought to your attention before. The story of the artificial sweetener Aspartame is illustrative of why that is so. The problem, in a word, is 'funding'. All research facilities need funding - either from the public sector or from private sources. By 1995 there were 165 published papers on Aspartame. They divided almost evenly between those that found no problems and those that raised questions. 100% of the studies that found no problems were funded by the manufacturer, 100% of those funded by non-industry sources raised questions. Much of the research that the FDA relies upon when assessing GMOs as fit for consumption is provided by their manufacturer, Monsanto.

In this article I've touched on a few of the problems raised by GMOs, but if you really want to scare yourself (as well as inform yourself) read the excellent 'Seeds of Deception' by Jeffrey Smith, from which these facts were taken. It exposes devastatingly the lies, deceits and deceptions that underpin the GM industry. You will also pray that Ireland remains GM free.